|
|
DAB Performance of different makes?
In article , Nobody
Here wrote: Jim Lesurf wrote: There was a time when the audio mags would do a thorough examination of new FM tuners, and show a great deal about their noise levels, interference rejection ability, etc. Yet almost nothing functionally equivalent seems to be done with DAB RXs. I find this quite baffling, and unsatisfactory since it fails to provide some potential users with info that they might find very helpful. I wonder if that's because of the perception that digital (DAB, TV whatever) either works of doesn't work, and that there's no middle ground? I suspect that is one of the main reasons. i.e. That a lot of the public have been led to think "digital works or it doesn't", when that is an over-simplification which may be misleading in many cases. Also, the mags, as has been pointed out many times before, have to keep their advertisers happy. Another part of the problem, I fear, is that this is also a consequence of the growth of "subjective" reviews in audio mags during the last 20-odd years. These are often done by people who make no measurements and have limited understanding of anything like RF or comms, or even the basics of digital systems. Thus they simply listen to a tuner and no-one seems to do any measurements which test for sensitivity, rejection of interference, etc, etc. I doubt many of them would know third-order intermod from a plate of sardines... This then tends to feed the lack of awareness of the possibility that RXs may vary in performance in real world situations. Slainte, Jim -- Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html |
DAB Performance of different makes?
Jim Lesurf wrote:
In article , DAB sounds worse than FM wrote: Jim Lesurf wrote: [snip] There will always be bit errors, and different DAB modules will perform differently. Yes! That is the kind of thing I have been asking about - with the aim of identifing the *actual* differences between *specific* RXs in various specific situations. For the reasons I have (twice) explained. The output BER is the all-important parameter, and two receivers which have an identical BER should provide effectively identical output audio quality (assuming, say, that the audio is routed via S/PDIF to the same DAC). I'd agree with the above, but with some qualifiers that are in accord with what you wrote lower down in your posting. One is that if different RXs have different sensitivities or level of interference rejection, then in some reception conditions different RXs will output different BERs from the same RF input. Agreed. This is why I think info on this would be of interest as it may affect some user's choice of RX. The other is the question of the 'strategy' a given RX takes to deal with a given sequence of uncorrectable errors when they arise. My experience with CD players and DACs is that when presented with a disc which produces a high enough level of uncorrectable errors the results can vary quite noticably. Yeah, Radioscape and Frontier-Silicon may well use different error concealment techniques. Thus my curiosity that this may also occur with DAB RXs. Some make 'mask' the errors in ways that make them less noticable than how other RXs handle the same sequence of errors, or produce artefacts that some find more/less annoying than others. It's possible, but you won't know if it's due to different error concealment techniques or there's a different number of errors in the first place. You'd have to start digging around in very low level stuff to know one way or another. This may for some people also matter. I'd agree that what they should do in improve reception and get down the level of errors, but for some people this may not be practical. Hence the usefulness of our finding out how RXs may vary in these respects. However, even with an identical output BER (the BER after the Viterbi decoder) there may be very slight differences between the performance of different DAB chipsets/modules. The possible differences could be caused by different implementations of the Viterbi algorithm such that the distribution of uncorrectable errors over the different parts of the audio frame are different. I'll explain what I mean by that: DAB uses UEP (unequal error protection) where different parts of the audio frame are protected with different error correction code rates: the audio frame header uses a low code rate for high protection, whereas the audio samples themselves use a higher code rate and thus offer lower protection. Therefore, if different chipsets/modules have implemented the Viterbi algorithm differently (e.g by using a different constraint length) then it is possible that the different chipsets/modules output a slightly different distritution of uncorrectable errors over the different parts of the audio frame, but still have the same overall output BER. Thanks for the above explanation. Yes, the above implies that there may be differences of the kind that I am curious about. Personally, I think this is very insignificant compared to other factors. Personally, I think it's unlikely that it is very unlikely that this would be significant, because the different code rate levels offer markedly different protection levels to the different parts of the audio frame, so I would say it is extremely likely that the distribution of errors over the different protection levels will be the same. In general, I am inclined to agree. My experience with other systems like CD players and DAC is that - given good signals - the differences tend to be slight for well made units. However what worries me in this area is the apparent lack of measurements and comparisons under a range of recpetion conditions. Hence we can assume that the differences will, generally, be small. Differences in what: audio quality or perceptibility of reception problems? Again, your wording is ambiguous. You started talking about CD players and DACs given good signals, which presumably means that the BER is very low, so there's no perceptible "reception" problems. But I dislike basing this on an assumption, however reasonable. I'd prefer evidence as my experince in engineering and science is that evidence sometimes shows unexpected results. e.g. here it may show that *some* RXs behave is a different way to others, and in a way that would have a significant effect for some users. Different receivers will have different RF performance, but this is -- or should be -- pretty irrelevant if the output BERs are equivalent, for the reason I've just given. That would be so if the BERs are equivalent, etc. However the problem is that if their RF sensitivities, etc, differ, then their BERs may also differ in some conditions of use. Obviously. You would expect the MP2 audio decoders would all pass the strict conformance requirements, but there probably will be very, very slight differences in the output PCM audio bitstream produced even for the same input data stream (but due to the strict conformance requirements I don't think this should be significant to the output audio quality). Again, I'd agree with that in principle, but I tend to prefer evidence from measurements on real RXs to see if any of them fall short of what is assumed or have unexpected 'features' in their behaviour. Good luck testing the MP2 decoders... No, I can't direct you to any evidence. There's 2 chipset/module design companies: Radioscape and Frontier-Silicon, and they account for probably 95% or more of all DAB receivers sold in the UK. They may use different RF front ends, but my impression is that receivers usually install full modules provided by these companies. Having said that, from reading people's experiences, there does seem variability of reception quality for things like DAB personal radios, so there may be some model-specific stuff as well. FWIW I bought a cheap 'DAB adaptor' a few weeks ago and use it some of the time for 'background listening' or for stations like BBC7. As you would expect, the sound quality on a station like BBC7 or World Service ahem isn't exactly perfect. This, I expected, of course. However what I am curious about is the following: One the main BBC stations the multiplex signal level is good enough for the RX to display "signal error 0" (whatever that means is undefined). But on, say, Classic FM, on its multiplex I get "signal error 3" (or a number in the range 2-5). Classic FM sounds worse to me that R3. This isn't surprising for reasons which I think will be obvious. However I am curious to know: Classic FM uses a bit rate of 160kbps. That's why it sounds poor. A) Would it sound any better if I improved the signal until I got "signal error 0"? B) Would a different RX give better results for the Classic FM multiplex in the same location? So, after I was slagged off for questioning your ambiguous wording the other day, now you're asking *precisely* what I suggested you were asking: do small differences in BER affect the audio quality. -- Steve - www.digitalradiotech.co.uk - Digital Radio News & Info Please sign the petition asking the BBC to provide better audio quality on its radio stations on DAB, Freeview, satellite and cable: http://tinyurl.com/a68e4 |
DAB Performance of different makes?
DAB sounds worse than FM wrote:
A) Would it sound any better if I improved the signal until I got "signal error 0"? B) Would a different RX give better results for the Classic FM multiplex in the same location? So, after I was slagged off for questioning your ambiguous wording the other day, now you're asking *precisely* what I suggested you were asking: do small differences in BER affect the audio quality. Caveat: I'm presuming that the difference in BER between "signal error 3" and "signal error 0" is small, but I don't know what it is either. -- Steve - www.digitalradiotech.co.uk - Digital Radio News & Info Please sign the petition asking the BBC to provide better audio quality on its radio stations on DAB, Freeview, satellite and cable: http://tinyurl.com/a68e4 |
DAB Performance of different makes?
In article , DAB sounds worse
than FM wrote: Jim Lesurf wrote: In article , DAB sounds worse than FM wrote: Thus my curiosity that this may also occur with DAB RXs. Some make 'mask' the errors in ways that make them less noticable than how other RXs handle the same sequence of errors, or produce artefacts that some find more/less annoying than others. It's possible, but you won't know if it's due to different error concealment techniques or there's a different number of errors in the first place. This is the kind of thing that might be revealed when someone (e.g. a magazine) actually records the series of samples produced by two RXs used in parallel to receive and decode the same input RF signal. (See the tests I describe below as an example.) You'd have to start digging around in very low level stuff to know one way or another. The test I've been hoping that a magazine would do is: A) Feed two RXs via a variable attenuator and a splitter, then record the outputs from, say, the two spdif outputs of the RXs as the atennuator is used to vary the input RF level presented to the two RXs. Then compare the series of values and look for differences. Doing this with two different models of RX would help show any differences between them in terms of dealing with poor RF input, or factors that affect the output. B) Feed two RXs of the same model/make, via a splitter, but with an attenuator in front of one of them. Record and compare the spdif outputs as above. This would indicate how the performance of a given model may be affected by the input RF level altering the BER, etc, it can produce. The performance could then be judged by the results since what I'm interested in here is if/how performance varies from one model to another and/or when the RF input level is altered. If there are no measured differences, then any possible differences in the internal arrangements may be irrelevant. But if differences show up, they may then cast a light on the possibility that one RX might be preferred by some customers to another. May also give an indication of the reasons in design terms. If the testers have a DAB generator they could use one RX at a time, as used to be stanadard for FM RXs. However in the absence of that, a good strong signal from an antenna could be used for the above by making the test signal 'common' to the two RXs being compared. To me, as someone who has worked on RF and mm-wave RX design over the years, tests like the above seem a fairly obvious and basic thing for reviewers to have done. It therefore is coming to intrigue me that I can't find the results of any such tests... Therefore, if different chipsets/modules have implemented the Viterbi algorithm differently (e.g by using a different constraint length) then it is possible that the different chipsets/modules output a slightly different distritution of uncorrectable errors over the different parts of the audio frame, but still have the same overall output BER. Thanks for the above explanation. Yes, the above implies that there may be differences of the kind that I am curious about. Personally, I think this is very insignificant compared to other factors. It may well be. The problem is that I can't find any results for tests like the ones I suggest above. Hence I can't find any actual objective data on this. Personally, I think it's unlikely that it is very unlikely that this would be significant, because the different code rate levels offer markedly different protection levels to the different parts of the audio frame, so I would say it is extremely likely that the distribution of errors over the different protection levels will be the same. In general, I am inclined to agree. My experience with other systems like CD players and DAC is that - given good signals - the differences tend to be slight for well made units. However what worries me in this area is the apparent lack of measurements and comparisons under a range of recpetion conditions. Hence we can assume that the differences will, generally, be small. Differences in what: audio quality or perceptibility of reception problems? Again, your wording is ambiguous. You started talking about CD players and DACs given good signals, which presumably means that the BER is very low, so there's no perceptible "reception" problems. The qualifier was "given good signals". The problem with RF reception is that this can't be assumed in all cases. (Indeed, it may not be the case with CDs, either, as some are faulty and hard for the player to read.) FWIW I bought a cheap 'DAB adaptor' a few weeks ago and use it some of the time for 'background listening' or for stations like BBC7. As you would expect, the sound quality on a station like BBC7 or World Service ahem isn't exactly perfect. This, I expected, of course. However what I am curious about is the following: One the main BBC stations the multiplex signal level is good enough for the RX to display "signal error 0" (whatever that means is undefined). But on, say, Classic FM, on its multiplex I get "signal error 3" (or a number in the range 2-5). Classic FM sounds worse to me that R3. This isn't surprising for reasons which I think will be obvious. However I am curious to know: Classic FM uses a bit rate of 160kbps. That's why it sounds poor. But how would the user know if seeing a message like "Signal error n" (where n != 0) indicated that a change might cause an audible improvement? I am not talking about the result becoming without any problems due to the chosen bitrate, but assessing any other problems. A) Would it sound any better if I improved the signal until I got "signal error 0"? B) Would a different RX give better results for the Classic FM multiplex in the same location? So, after I was slagged off for questioning your ambiguous wording the other day, now you're asking *precisely* what I suggested you were asking: do small differences in BER affect the audio quality. Not quite. I am asking about what may be *large* differences or BERs in some cases as well as *small* ones in others. I am also asking how the BER values and concealment behaviours of RXs compare over a wide range of RF reception conditions. i.e. to reference this to the RF available to the (various) users. FWIW I have no idea what "signal error 2" actually means on the 'adaptor' I'm using. Hence I can't tell if indicates what you/I would call a high BER or a low BER. All I can surmise is that it seems probable that it indicates a BER higher than for "signal error 0". However my interest isn't confined to just that single adaptor, but extend to all the RXs on sale, and the range of conditions of use that they may experience. The problem is that until someone does the relevant measurements this can't be reliably assessed. It will be no surprise to discover that if we have reasonably high level and clean RF inputs, the BERs will be low, and the RXs may then tend to sound similar or indistinguishable. But what about under poorer reception conditions? Slainte, Jim -- Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html |
DAB Performance of different makes?
Jim Lesurf wrote:
Classic FM sounds worse to me that R3. This isn't surprising for reasons which I think will be obvious. However I am curious to know: A) Would it sound any better if I improved the signal until I got "signal error 0"? Have you tried the obvious simple test?: Increase the BER on the BBC mux to "signal error 3" and see if you can perceive any difference. Try scrunching up the wire aerial and/or move the receiver. -- Steve - www.digitalradiotech.co.uk - Digital Radio News & Info Please sign the petition asking the BBC to provide better audio quality on its radio stations on DAB, Freeview, satellite and cable: http://tinyurl.com/a68e4 |
DAB Performance of different makes?
In article , DAB sounds worse
than FM wrote: DAB sounds worse than FM wrote: A) Would it sound any better if I improved the signal until I got "signal error 0"? B) Would a different RX give better results for the Classic FM multiplex in the same location? So, after I was slagged off for questioning your ambiguous wording the other day, now you're asking *precisely* what I suggested you were asking: do small differences in BER affect the audio quality. Caveat: I'm presuming that the difference in BER between "signal error 3" and "signal error 0" is small, but I don't know what it is either. Yes, in this example case, we can't tell what it means as the makers give no info on what the value is supposed to me. This is a part of what I think is a more general problem due to a lack of measurements or performance definitions. For all I know Classic FM would sound the same if the value was "0" as it does when the value is in the range 2-4. Or it might sound noticably different. Can't be sure. I'm just using this as an example as I tend not to listen to Classic FM anyway. But it illuminates the sort of problems I'm curious about. The makers do not provide the necessary info to interpret the numbers. Nor do reviews seem to give any info on this - for the various RXs I've seen. Hence if someone has poor reception conditions, how can they judge before they buy what RXs might - for them - function worse than others? No data to make comparisions and reach decisions. If the reception conditions are good, then it may not really matter. But the potential buyer/user may not know this in advance, and so if in a poor location may chose the 'wrong' RX due to lack of relevant info. This is why I am interested in discovering the relevant data I've been asking about, and why I am now intrigued/puzzled by the apparent lack of any tests by magazines, etc, to produce it for readers... Slainte, Jim -- Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html |
DAB Performance of different makes?
Jim Lesurf wrote:
In article , DAB sounds worse than FM wrote: Jim Lesurf wrote: In article , DAB sounds worse than FM wrote: Thus my curiosity that this may also occur with DAB RXs. Some make 'mask' the errors in ways that make them less noticable than how other RXs handle the same sequence of errors, or produce artefacts that some find more/less annoying than others. It's possible, but you won't know if it's due to different error concealment techniques or there's a different number of errors in the first place. This is the kind of thing that might be revealed when someone (e.g. a magazine) actually records the series of samples produced by two RXs used in parallel to receive and decode the same input RF signal. (See the tests I describe below as an example.) If you're talking about comparing audio samples then you have to bear in mind that this is perceptually codec audio. You'd have to start digging around in very low level stuff to know one way or another. The test I've been hoping that a magazine would do is: A) Feed two RXs via a variable attenuator and a splitter, then record the outputs from, say, the two spdif outputs of the RXs as the atennuator is used to vary the input RF level presented to the two RXs. Then compare the series of values and look for differences. Doing this with two different models of RX would help show any differences between them in terms of dealing with poor RF input, or factors that affect the output. Seeing as different make receivers are likely to differ significantly, e.g. in their sensitivies, and considering that the audio is perceptually codec, then I think such a comparison would be near-meangingless. For example, how can you tell that a difference in the waveform is actually perceptible? B) Feed two RXs of the same model/make, via a splitter, but with an attenuator in front of one of them. Record and compare the spdif outputs as above. This would indicate how the performance of a given model may be affected by the input RF level altering the BER, etc, it can produce. That's reasonable, but how are you going to access the true BER? The performance could then be judged by the results since what I'm interested in here is if/how performance varies from one model to another and/or when the RF input level is altered. If there are no measured differences, then any possible differences in the internal arrangements may be irrelevant. There will be measured differences, but what do these measured differences prove?? Are the errors below or above the psychoacoustic masking curves in the frequency domain? If they're below then you shouldn't be able to perceive them. But how are you going to access the psychoacoustic masking curves that are only accessible internal to the chip/software? All your traditional tests go out of the window with perceptually coded audio, I'm afraid. But if differences show up, they may then cast a light on the possibility that one RX might be preferred by some customers to another. So, you WERE talking about audio quality ALL ALONG, which is what I said in the first place. But oh no, I get accused of mis-interpreting your ambiguously worded paragraph. May also give an indication of the reasons in design terms. If the testers have a DAB generator they could use one RX at a time, as used to be stanadard for FM RXs. However in the absence of that, a good strong signal from an antenna could be used for the above by making the test signal 'common' to the two RXs being compared. To me, as someone who has worked on RF and mm-wave RX design over the years, tests like the above seem a fairly obvious and basic thing for reviewers to have done. They're meaningless. In general, I am inclined to agree. My experience with other systems like CD players and DAC is that - given good signals - the differences tend to be slight for well made units. However what worries me in this area is the apparent lack of measurements and comparisons under a range of recpetion conditions. Hence we can assume that the differences will, generally, be small. Differences in what: audio quality or perceptibility of reception problems? Again, your wording is ambiguous. You started talking about CD players and DACs given good signals, which presumably means that the BER is very low, so there's no perceptible "reception" problems. The qualifier was "given good signals". The problem with RF reception is that this can't be assumed in all cases. (Indeed, it may not be the case with CDs, either, as some are faulty and hard for the player to read.) But are you talking about audio quality differences? If so, then why TF was I accused of jumping to the wrong conclusions???? FWIW I bought a cheap 'DAB adaptor' a few weeks ago and use it some of the time for 'background listening' or for stations like BBC7. As you would expect, the sound quality on a station like BBC7 or World Service ahem isn't exactly perfect. This, I expected, of course. However what I am curious about is the following: One the main BBC stations the multiplex signal level is good enough for the RX to display "signal error 0" (whatever that means is undefined). But on, say, Classic FM, on its multiplex I get "signal error 3" (or a number in the range 2-5). Classic FM sounds worse to me that R3. This isn't surprising for reasons which I think will be obvious. However I am curious to know: Classic FM uses a bit rate of 160kbps. That's why it sounds poor. But how would the user know if seeing a message like "Signal error n" (where n != 0) indicated that a change might cause an audible improvement? They wouldn't know. I am not talking about the result becoming without any problems due to the chosen bitrate, but assessing any other problems. A) Would it sound any better if I improved the signal until I got "signal error 0"? B) Would a different RX give better results for the Classic FM multiplex in the same location? So, after I was slagged off for questioning your ambiguous wording the other day, now you're asking *precisely* what I suggested you were asking: do small differences in BER affect the audio quality. Not quite. I am asking about what may be *large* differences or BERs in some cases as well as *small* ones in others. That sentence doesn't make sense. I am also asking how the BER values and concealment behaviours of RXs compare over a wide range of RF reception conditions. i.e. to reference this to the RF available to the (various) users. FWIW I have no idea what "signal error 2" actually means on the 'adaptor' I'm using. Hence I can't tell if indicates what you/I would call a high BER or a low BER. All I can surmise is that it seems probable that it indicates a BER higher than for "signal error 0". Obviously. However my interest isn't confined to just that single adaptor, but extend to all the RXs on sale, and the range of conditions of use that they may experience. The problem is that until someone does the relevant measurements this can't be reliably assessed. It will be no surprise to discover that if we have reasonably high level and clean RF inputs, the BERs will be low, and the RXs may then tend to sound similar or indistinguishable. But what about under poorer reception conditions? Under poor reception conditions you get bubbling mud. The audio quality probably degrades just before the onset of bubbling mud, but so long as the BER is lower than some given value then I'd bet you wouldn't be able to perceive any difference (assuming they're using the same DAC) between receivers. I don't know exactly what that BER is (and this BER is for the audio samples, because the BER of the header and scale factors will be diffferent due to different code rates being used for them), but basically so long as you have reasonable reception and the same DAC is being used then I say the differences will be imperceptible. Will there be measurable differences? Yeah, but they'd be meaningless if you can't hear any difference, becauase it's perceptually coded audio. -- Steve - www.digitalradiotech.co.uk - Digital Radio News & Info Please sign the petition asking the BBC to provide better audio quality on its radio stations on DAB, Freeview, satellite and cable: http://tinyurl.com/a68e4 |
DAB Performance of different makes?
DAB sounds worse than FM wrote:
Jim Lesurf wrote: In article , DAB sounds worse than FM wrote: Jim Lesurf wrote: In article , DAB sounds worse than FM wrote: Thus my curiosity that this may also occur with DAB RXs. Some make 'mask' the errors in ways that make them less noticable than how other RXs handle the same sequence of errors, or produce artefacts that some find more/less annoying than others. It's possible, but you won't know if it's due to different error concealment techniques or there's a different number of errors in the first place. This is the kind of thing that might be revealed when someone (e.g. a magazine) actually records the series of samples produced by two RXs used in parallel to receive and decode the same input RF signal. (See the tests I describe below as an example.) If you're talking about comparing audio samples then you have to bear in mind that this is perceptually codec audio. You'd have to start digging around in very low level stuff to know one way or another. The test I've been hoping that a magazine would do is: A) Feed two RXs via a variable attenuator and a splitter, then record the outputs from, say, the two spdif outputs of the RXs as the atennuator is used to vary the input RF level presented to the two RXs. Then compare the series of values and look for differences. Doing this with two different models of RX would help show any differences between them in terms of dealing with poor RF input, or factors that affect the output. Seeing as different make receivers are likely to differ significantly, e.g. in their sensitivies, and considering that the audio is perceptually codec, then I think such a comparison would be near-meangingless. For example, how can you tell that a difference in the waveform is actually perceptible? But is *exactly* the reason for performing the test in the first place. The receivers *are* different, and the test might tell you how much better one of them was compared with the other. If the difference is *significant* then surely it's *important*, not *meaningless*. Sigh. Oh, I forgot, the dope's not listening to me any more. -- Nobby |
DAB Performance of different makes?
Jim Lesurf wrote:
In article , DAB sounds worse than FM wrote: DAB sounds worse than FM wrote: A) Would it sound any better if I improved the signal until I got "signal error 0"? B) Would a different RX give better results for the Classic FM multiplex in the same location? So, after I was slagged off for questioning your ambiguous wording the other day, now you're asking *precisely* what I suggested you were asking: do small differences in BER affect the audio quality. Caveat: I'm presuming that the difference in BER between "signal error 3" and "signal error 0" is small, but I don't know what it is either. Yes, in this example case, we can't tell what it means as the makers give no info on what the value is supposed to me. This is a part of what I think is a more general problem due to a lack of measurements or performance definitions. For all I know Classic FM would sound the same if the value was "0" as it does when the value is in the range 2-4. Or it might sound noticably different. Do you know what the "signal error" goes up to? In my experience, there's no difference in audio quality from when there's maximum signal quality down to when the bubbling mud actually starts. Can't be sure. I'm just using this as an example as I tend not to listen to Classic FM anyway. But it illuminates the sort of problems I'm curious about. The makers do not provide the necessary info to interpret the numbers. Nor do reviews seem to give any info on this - for the various RXs I've seen. Hence if someone has poor reception conditions, how can they judge before they buy what RXs might - for them - function worse than others? No data to make comparisions and reach decisions. You seem to be flitting between talking about reception problems and audio quality problems. -- Steve - www.digitalradiotech.co.uk - Digital Radio News & Info Please sign the petition asking the BBC to provide better audio quality on its radio stations on DAB, Freeview, satellite and cable: http://tinyurl.com/a68e4 |
DAB Performance of different makes?
In article , DAB sounds worse
than FM wrote: Jim Lesurf wrote: Classic FM sounds worse to me that R3. This isn't surprising for reasons which I think will be obvious. However I am curious to know: A) Would it sound any better if I improved the signal until I got "signal error 0"? Have you tried the obvious simple test?: Increase the BER on the BBC mux to "signal error 3" and see if you can perceive any difference. Try scrunching up the wire aerial and/or move the receiver. I've been meaning to do this. Also to take the system into the living room and use it with the better audio system. However so far I haven't bothered as I mainly use it for occasional 'background' listening to R7/WS. Most of the time I listen to R3/4 on FM. Slainte, Jim -- Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html |
DAB Performance of different makes?
In article , DAB sounds worse
than FM wrote: Jim Lesurf wrote: In article , DAB sounds worse than FM wrote: The test I've been hoping that a magazine would do is: A) Feed two RXs via a variable attenuator and a splitter, then record the outputs from, say, the two spdif outputs of the RXs as the atennuator is used to vary the input RF level presented to the two RXs. Then compare the series of values and look for differences. Doing this with two different models of RX would help show any differences between them in terms of dealing with poor RF input, or factors that affect the output. Seeing as different make receivers are likely to differ significantly, e.g. in their sensitivies, and considering that the audio is perceptually codec, then I think such a comparison would be near-meangingless. Not if carried out in conjunction with (B) below as we could then assess which tuner might be preferred by someone who only had a low RF level which affected one tuner more than another. It would also test the idea that "all tuners behave in the same way" and see if it was applicable to the two being tested. For example, how can you tell that a difference in the waveform is actually perceptible? Before we could decide that, we'd need to establish that the outputs *do* differ. That is one of the purposes of the test. Given that the test showed differences the reviewer/tester could then go on to consider and assess any perceptable differences and judge them. B) Feed two RXs of the same model/make, via a splitter, but with an attenuator in front of one of them. Record and compare the spdif outputs as above. This would indicate how the performance of a given model may be affected by the input RF level altering the BER, etc, it can produce. That's reasonable, but how are you going to access the true BER? That isn't the purpose of the test. To do that we'd need either an RX whose performance was 'guaranteed' in some way, or a test signal whose actual details were defined. The purpose of the test would be to see at what power levels that design started to show effects due to the input RF CNR being low enough to give it problems that affected the output. The performance could then be judged by the results since what I'm interested in here is if/how performance varies from one model to another and/or when the RF input level is altered. If there are no measured differences, then any possible differences in the internal arrangements may be irrelevant. There will be measured differences, but what do these measured differences prove?? "Prove" is not the appropriate term when using the scientific method. The aim is to provide evidence and test hypotheses. In those terms the aims include: 1) Seeing that the results may (or may not) vary from one design to another, in specific cases. 2) The signal levels at which a given design starts to have its output affected significantly by the available RF CNR. Are the errors below or above the psychoacoustic masking curves in the frequency domain? See above. If the tuner designs behave in the same way, then there would be no need to consider - in terms of perception - what audible differences there might be. If they do differ, that could be assessed, and then compared with the kinds of measured differences that might be observed. If they're below then you shouldn't be able to perceive them. But how are you going to access the psychoacoustic masking curves that are only accessible internal to the chip/software? That is not the purpose of the tests. All your traditional tests go out of the window with perceptually coded audio, I'm afraid. The perceptial tests are for a different purpose. But if differences show up, they may then cast a light on the possibility that one RX might be preferred by some customers to another. So, you WERE talking about audio quality ALL ALONG, which is what I said in the first place. But oh no, I get accused of mis-interpreting your ambiguously worded paragraph. Nope. I'm afraid you are once again, misunderstanding what I am saying. I am suggesting objective tests to measure any differences in the outputs from different designs, or under different conditions of use. These tests in themselves, say nothing at all about how any differences may or may not be percieved or assessed in terms of judgements on the resulting sound. May also give an indication of the reasons in design terms. If the testers have a DAB generator they could use one RX at a time, as used to be stanadard for FM RXs. However in the absence of that, a good strong signal from an antenna could be used for the above by making the test signal 'common' to the two RXs being compared. To me, as someone who has worked on RF and mm-wave RX design over the years, tests like the above seem a fairly obvious and basic thing for reviewers to have done. They're meaningless. if you wish to use the results for some purpose for which the tests are not intended. :-) But are you talking about audio quality differences? If so, then why TF was I accused of jumping to the wrong conclusions???? Because I was not, and you are, I am afraid, once again jumping to the same wrong conclusions. So, after I was slagged off for questioning your ambiguous wording the other day, now you're asking *precisely* what I suggested you were asking: do small differences in BER affect the audio quality. Not quite. I am asking about what may be *large* differences or BERs in some cases as well as *small* ones in others. That sentence doesn't make sense. Afraid it does to me. And from what others have already said in this thread, I think that others will understand it. I'm afraid that once again you are misunderstaning what I am explaining. However my interest isn't confined to just that single adaptor, but extend to all the RXs on sale, and the range of conditions of use that they may experience. The problem is that until someone does the relevant measurements this can't be reliably assessed. It will be no surprise to discover that if we have reasonably high level and clean RF inputs, the BERs will be low, and the RXs may then tend to sound similar or indistinguishable. But what about under poorer reception conditions? Under poor reception conditions you get bubbling mud. But some RXs may have a lower noise figure (high sensitivity) than others, and hence the use of one RX might give better results than another. Perhaps markedly better. Hence the need for suitable tests to see if and when this may be the case, to aid those who do not have ideal reception conditions. The audio quality probably degrades just before the onset of bubbling mud, but so long as the BER is lower than some given value then I'd bet you wouldn't be able to perceive any difference (assuming they're using the same DAC) between receivers. You may well be right. But that isn't what I am talking about as I am concerned with situations where one RX may give a high BER, but another give a low BER, and the user might want to know which of this did which before they buy. Slainte, Jim -- Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html |
DAB Performance of different makes?
Hi,
Many thanks for all your comments to my original question about DAB performance. I now know a little more about the subject than a week ago, after reading your comments, and doing some research on the net! My requirements in respect of audio quality are very modest, and I'm more interested in reliability of DAB reception with a minimal aerial. Ideally a clock radio,with DAB, FM, internal speakers, CD & remote control. Unfortunately it's very difficult to get a full technical spec of these products, even of the simple, easy to measure items, such as standby power, and backup battery drain, let alone the weak signal performance of DAB! I've now found that the Intempo RS-01 clock radio appears to match my requirements. Has anyone had any experience with that make? Regards Clive |
DAB Performance of different makes?
In article , DAB sounds worse
than FM wrote: Jim Lesurf wrote: For all I know Classic FM would sound the same if the value was "0" as it does when the value is in the range 2-4. Or it might sound noticably different. Do you know what the "signal error" goes up to? No. Not bothered to experiment much with the specific 'adaptor' as I don't expect much from it in any case, and simply use it for general listening whilst doing things like posting to usenet. :-) In my experience, there's no difference in audio quality from when there's maximum signal quality down to when the bubbling mud actually starts. But is that based on varying the input RF level in a controlled manner? And a perception/judgement isn't the type of measurement I am interested in at this point. Can't be sure. I'm just using this as an example as I tend not to listen to Classic FM anyway. But it illuminates the sort of problems I'm curious about. The makers do not provide the necessary info to interpret the numbers. Nor do reviews seem to give any info on this - for the various RXs I've seen. Hence if someone has poor reception conditions, how can they judge before they buy what RXs might - for them - function worse than others? No data to make comparisions and reach decisions. You seem to be flitting between talking about reception problems and audio quality problems. I'm simply accepting that one *may* lead to the other in at least some cases. But then pointing out that without relevant measurements, we can't tell one way or the other... The problem is the absence of data on this means we only have reasonable assumptions to go on. Slainte, Jim -- Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html |
DAB Performance of different makes?
Jim Lesurf wrote:
In article , DAB sounds worse than FM wrote: Jim Lesurf wrote: In article , DAB sounds worse than FM wrote: The test I've been hoping that a magazine would do is: A) Feed two RXs via a variable attenuator and a splitter, then record the outputs from, say, the two spdif outputs of the RXs as the atennuator is used to vary the input RF level presented to the two RXs. Then compare the series of values and look for differences. Doing this with two different models of RX would help show any differences between them in terms of dealing with poor RF input, or factors that affect the output. Seeing as different make receivers are likely to differ significantly, e.g. in their sensitivies, and considering that the audio is perceptually codec, then I think such a comparison would be near-meangingless. Not if carried out in conjunction with (B) below as we could then assess which tuner might be preferred by someone who only had a low RF level which affected one tuner more than another. Okay. It would also test the idea that "all tuners behave in the same way" and see if it was applicable to the two being tested. For example, how can you tell that a difference in the waveform is actually perceptible? Before we could decide that, we'd need to establish that the outputs *do* differ. That is one of the purposes of the test. Given that the test showed differences the reviewer/tester could then go on to consider and assess any perceptable differences and judge them. Yes, so you want to see if the audio quality changes. Which is, erm, what I've said you wanted to do all along, or at least one of the things you want to do, with the other being comparing how well receivers perform with weak signals. The performance could then be judged by the results since what I'm interested in here is if/how performance varies from one model to another and/or when the RF input level is altered. If there are no measured differences, then any possible differences in the internal arrangements may be irrelevant. There will be measured differences, but what do these measured differences prove?? "Prove" is not the appropriate term when using the scientific method. Yawn. The aim is to provide evidence and test hypotheses. In those terms the aims include: 1) Seeing that the results may (or may not) vary from one design to another, in specific cases. Yes, you want to compare the audio quality. 2) The signal levels at which a given design starts to have its output affected significantly by the available RF CNR. Are the errors below or above the psychoacoustic masking curves in the frequency domain? See above. If the tuner designs behave in the same way, then there would be no need to consider - in terms of perception - what audible differences there might be. If they do differ, that could be assessed, and then compared with the kinds of measured differences that might be observed. Yes, you want to see if the audio quality changes. But if differences show up, they may then cast a light on the possibility that one RX might be preferred by some customers to another. So, you WERE talking about audio quality ALL ALONG, which is what I said in the first place. But oh no, I get accused of mis-interpreting your ambiguously worded paragraph. Nope. I'm afraid you are once again, I'm afraid I'm not. misunderstanding what I am saying. No I'm not. I am suggesting objective tests to measure any differences in the outputs from different designs, or under different conditions of use. These tests in themselves, say nothing at all about how any differences may or may not be percieved or assessed in terms of judgements on the resulting sound. But above you are saying that you want to do tests to see if different receivers produce different audio quality. But are you talking about audio quality differences? If so, then why TF was I accused of jumping to the wrong conclusions???? Because I was not, and you are, I am afraid, once again jumping to the same wrong conclusions. No I'm not, sorry. So, after I was slagged off for questioning your ambiguous wording the other day, now you're asking *precisely* what I suggested you were asking: do small differences in BER affect the audio quality. Not quite. I am asking about what may be *large* differences or BERs in some cases as well as *small* ones in others. That sentence doesn't make sense. Afraid it does to me. Sorry, it doesn't make sense. YOu might understand it, because you wrote it and you understsand what you meant to say, and I can guess what you mean, but it doesn't actually make sense as a sentence. And from what others have already said in this thread, I think that others will understand it. What, you ask the question, which is basically, "who do you believe, the nice polite Jim, or nasty Steve who likes to be rude?", and you're surprised at the response? I see. I'm afraid that once again you are misunderstaning what I am explaining. No, you just can't admit to making mistakes. However my interest isn't confined to just that single adaptor, but extend to all the RXs on sale, and the range of conditions of use that they may experience. The problem is that until someone does the relevant measurements this can't be reliably assessed. It will be no surprise to discover that if we have reasonably high level and clean RF inputs, the BERs will be low, and the RXs may then tend to sound similar or indistinguishable. But what about under poorer reception conditions? Under poor reception conditions you get bubbling mud. But some RXs may have a lower noise figure (high sensitivity) than others, Obviously. and hence the use of one RX might give better results than another. Obviously. Perhaps markedly better. Obviously. Hence the need for suitable tests to see if and when this may be the case, to aid those who do not have ideal reception conditions. The audio quality probably degrades just before the onset of bubbling mud, but so long as the BER is lower than some given value then I'd bet you wouldn't be able to perceive any difference (assuming they're using the same DAC) between receivers. You may well be right. But that isn't what I am talking about as I am concerned with situations where one RX may give a high BER, but another give a low BER, Oooooooooooooooooooooh, that's what you're doing, *is it*? That's not what you've been saying. Sorry. You're trying to now say that you're only interested in large differences in BER, when beforehand you've been going on about comparing the audio quality from small changes in BER and even comparing the audio quality from equal BER values. Make your mind up. But, of course, I'll just be accused of mis-intepreting what you've said, again, and your merry band of supporters will raise their hands and say "Yes, Jim, I understand fully what you've said, your use of the English language is perfect, with no hint of ambiguity, and your explanations are possibly the most lucidly-written pieces of text I have ever read in my entire life. In fact, it's a shame I'm male, because I would like to have your children." -- Steve - www.digitalradiotech.co.uk - Digital Radio News & Info Please sign the petition asking the BBC to provide better audio quality on its radio stations on DAB, Freeview, satellite and cable: http://tinyurl.com/a68e4 |
DAB Performance of different makes?
In article , DAB sounds worse
than FM wrote: Jim Lesurf wrote: In article , DAB sounds worse than FM wrote: Jim Lesurf wrote: Before we could decide that, we'd need to establish that the outputs *do* differ. That is one of the purposes of the test. Given that the test showed differences the reviewer/tester could then go on to consider and assess any perceptable differences and judge them. Yes, so you want to see if the audio quality changes. Not quite. The primary purpose of the tests I am describing and asking for is to obtain *measurements* in objective terms of the information emerging from the RXs. Should the sample values show differences in the tests, then we could decide to assess them in terms of audio quality. But what I am looking for is the actual measurements first. Data first, then interpretation or assessment/judgements may come later. The aim is to provide evidence and test hypotheses. In those terms the aims include: 1) Seeing that the results may (or may not) vary from one design to another, in specific cases. Yes, you want to compare the audio quality. cf above. [snip] Yes, you want to see if the audio quality changes. cf above. [snip] I am suggesting objective tests to measure any differences in the outputs from different designs, or under different conditions of use. These tests in themselves, say nothing at all about how any differences may or may not be percieved or assessed in terms of judgements on the resulting sound. But above you are saying that you want to do tests to see if different receivers produce different audio quality. cf above. But are you talking about audio quality differences? If so, then why TF was I accused of jumping to the wrong conclusions???? Because I was not, and you are, I am afraid, once again jumping to the same wrong conclusions. No I'm not, sorry. Sez you. ;- [Shall skip going on to, "My dad is bigger than your dad!"...? :-) ] So, after I was slagged off for questioning your ambiguous wording the other day, now you're asking *precisely* what I suggested you were asking: do small differences in BER affect the audio quality. Not quite. I am asking about what may be *large* differences or BERs in some cases as well as *small* ones in others. That sentence doesn't make sense. Afraid it does to me. Sorry, it doesn't make sense. YOu might understand it, because you wrote it and you understsand what you meant to say, and I can guess what you mean, but it doesn't actually make sense as a sentence. OK. Let's check: Does anyone else who is reading this not understand what I wrote? And from what others have already said in this thread, I think that others will understand it. What, you ask the question, which is basically, "who do you believe, the nice polite Jim, or nasty Steve who likes to be rude?", and you're surprised at the response? I see. If you feel that you behave in a rude way, and that others will disagree with you for that reason, then I'd suggest that the remedy is obvious, and in your control. :-) I'm afraid that once again you are misunderstaning what I am explaining. No, you just can't admit to making mistakes. Erm... "yawn" (TM) :-) BTW Following the implication of what you wrote above, you may find it more useful to be polite when discussing technical matters. My experience is that people take you more seriously that way than if you resort to making assertions like the above as soon as you don't follow something or disagree with it. To me, when you make comments like the above is does seem a bit like, "go for the man, not the ball". Maybe others find that approach convincing, but I am afraid that I do not. You may also find this helpful when writing webpages, magazine articles, etc, if you wish a sympathetic and supportive response from readers. Your call, though. Hence the need for suitable tests to see if and when this may be the case, to aid those who do not have ideal reception conditions. The audio quality probably degrades just before the onset of bubbling mud, but so long as the BER is lower than some given value then I'd bet you wouldn't be able to perceive any difference (assuming they're using the same DAC) between receivers. You may well be right. But that isn't what I am talking about as I am concerned with situations where one RX may give a high BER, but another give a low BER, Oooooooooooooooooooooh, that's what you're doing, *is it*? That's not what you've been saying. Lets check: Anyone else agree with Steve? Or do others think what I've been writing is reasonable clear and consistent? Sorry. You're trying to now say that you're only interested in large differences in BER, when beforehand you've been going on about comparing the audio quality from small changes in BER and even comparing the audio quality from equal BER values. Make your mind up. Shame that you couldn't resist adding "Make your mind up". My interest is in the various things I have described which may affect the *output* of the RXs in *measureable* terms. One of the obvious factors will be how CNR may affect BER But, of course, I'll just be accused of mis-intepreting what you've said, again, It is not an "accusation" to point out that someone has misunderstood something. I am afraid you are having an emotional reaction when none is needed. and your merry band of supporters will raise their hands and say "Yes, Jim, I understand fully what you've said, your use of the English language is perfect, with no hint of ambiguity, and your explanations are possibly the most lucidly-written pieces of text I have ever read in my entire life. In fact, it's a shame I'm male, because I would like to have your children." I can't recall anyone actually responding in that way, TBH. More likely that most sensible people wandered off down to pub ages ago... :-) In one way it might seem quite flattering to think that I have a "merry band of supporters". However I am not entirely sure the idea is accurate. It seems to rather under-regard other people here. Also: If there is a fan club, should I not have a membership badge, or something? That said, rather than diverting the discussion to me and a hypothetical "merry band", I'd prefer to focus on the technical issues I have been raising. Although it looks like no results of the kinds of tests I am interested in is available, which is a dissapointment. FWIW I don't really know why you tend to react in such emotional ways to what I have been writing. There are far worse things in the real world to get concerned about. Relax. This isn't worth getting yourself upset about. Slainte, Jim -- Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html |
DAB Performance of different makes?
....and I would like to know about aeroplanes. When I had builders here
for a couple of weeks with their portable DAB radio, every passing aeroplane introduced a lot of noisy interference. The planes here - approx 15 miles from Heathrow - are quite high (virtually inaudible) but bloody frequent. Does that mean no DAB for me? Stan |
DAB Performance of different makes?
Stan The Man wrote: ...and I would like to know about aeroplanes. When I had builders here for a couple of weeks with their portable DAB radio, every passing aeroplane introduced a lot of noisy interference. The planes here - approx 15 miles from Heathrow - are quite high (virtually inaudible) but bloody frequent. Does that mean no DAB for me? I sit in Heathrow airport on an almost weekly basis waiting to board planes and listening to my DAB Walkman. Works fine. |
DAB Performance of different makes?
DAB sounds worse than FM wrote:
Actually, I did read your posts on Google Groups this morning to see your reaction to being blocked, So you hide someone's posts from your view and then you're so inquisitive to read them you circumvent your own killfile? I think you might do your own sanity a favour (not to mention everyone else's) if you took, say, a 1 month break from usenet... |
DAB Performance of different makes?
Jim Lesurf wrote:
In article , DAB sounds worse than FM wrote: Jim Lesurf wrote: In article , DAB sounds worse than FM wrote: Jim Lesurf wrote: Before we could decide that, we'd need to establish that the outputs *do* differ. That is one of the purposes of the test. Given that the test showed differences the reviewer/tester could then go on to consider and assess any perceptable differences and judge them. Yes, so you want to see if the audio quality changes. Not quite. The primary purpose of the tests I am describing and asking for is to obtain *measurements* in objective terms of the information emerging from the RXs. Should the sample values show differences in the tests, then we could decide to assess them in terms of audio quality. But what I am looking for is the actual measurements first. Data first, then interpretation or assessment/judgements may come later. Right, I see, so you want to see if the audio quality changes. So, after I was slagged off for questioning your ambiguous wording the other day, now you're asking *precisely* what I suggested you were asking: do small differences in BER affect the audio quality. Not quite. I am asking about what may be *large* differences or BERs in some cases as well as *small* ones in others. That sentence doesn't make sense. Afraid it does to me. Sorry, it doesn't make sense. YOu might understand it, because you wrote it and you understsand what you meant to say, and I can guess what you mean, but it doesn't actually make sense as a sentence. OK. Let's check: Does anyone else who is reading this not understand what I wrote? Yeah, let's appeal to the anti-Steve brigade to see how many people disagree with nasty Steve. And from what others have already said in this thread, I think that others will understand it. What, you ask the question, which is basically, "who do you believe, the nice polite Jim, or nasty Steve who likes to be rude?", and you're surprised at the response? I see. If you feel that you behave in a rude way, and that others will disagree with you for that reason, then I'd suggest that the remedy is obvious, and in your control. :-) That is entirely irrelevant to whether I'm correct or not. I'm afraid that once again you are misunderstaning what I am explaining. No, you just can't admit to making mistakes. Erm... "yawn" (TM) :-) BTW Following the implication of what you wrote above, you may find it more useful to be polite when discussing technical matters. My experience is that people take you more seriously that way than if you resort to making assertions like the above as soon as you don't follow something or disagree with it. Here you go again with your "resort to making assertions like the above as soon as you don't follow something". Who TF do you think you are? The end result you're trying to compare is THE AUDIO QUALITY as a result of differences in receivers. This is what you said originally: " If it is the case that different DAB RXs give differing outputs when fed with the same DAB signal, then it may have some impact on the assessment of DAB that people keep making/assuming." I have not been wrong AT ALL in this discussion. Sorry. I know you're trying to compare RF performance etc, but you're also comparing the audio quality of different receivers, and with your wording in the above paragraph that shows that you're trying to suggest, or you want to test, whether different receivers "may have some impact on the assessment of DAB that people keep making/assuming" Sorry, but this is what I've been saying all along, and you've continually tried to weasel your way out of admitting it. To me, when you make comments like the above is does seem a bit like, "go for the man, not the ball". Maybe others find that approach convincing, but I am afraid that I do not. I'm not going for "the man", I'm going for what you said originally, and you're now explicitly saying what I thought you were doing all along, AND YOU'RE STILL DENYING WHAT YOU'RE DOING AND YOU'RE STILL ACCUSING ME OF BEING WRONG. FFS. You may also find this helpful when writing webpages, magazine articles, etc, if you wish a sympathetic and supportive response from readers. Save the sanctimonious lecture for someone else. In a magazine or on my website I will write in a different manner to how I write on here, because this is Usenet. Your call, though. Hence the need for suitable tests to see if and when this may be the case, to aid those who do not have ideal reception conditions. The audio quality probably degrades just before the onset of bubbling mud, but so long as the BER is lower than some given value then I'd bet you wouldn't be able to perceive any difference (assuming they're using the same DAC) between receivers. You may well be right. But that isn't what I am talking about as I am concerned with situations where one RX may give a high BER, but another give a low BER, Oooooooooooooooooooooh, that's what you're doing, *is it*? That's not what you've been saying. Lets check: Anyone else agree with Steve? Or do others think what I've been writing is reasonable clear and consistent? This is what you said: " If it is the case that different DAB RXs give differing outputs when fed with the same DAB signal, then it may have some impact on the assessment of DAB that people keep making/assuming." And it does turn out that you want to compare different receivers to see if things like the RF sensitivity etc alters the output audio quality. THAT IS PRECISELY WHAT I'VE BEEN SAYING ALL ALONG, AND YOU'RE STILL DENYING THAT YOU WANT TO COMPARE AUDIO QUALITY. You slagged off spiney the other day for being someone that's exasperating and will not listen to reason, and yet you're saying totally contradictory things in the same post: you want to compare the output audio quality, but you're also saying you don't want to compare the output audio quality. Sorry. You're trying to now say that you're only interested in large differences in BER, when beforehand you've been going on about comparing the audio quality from small changes in BER and even comparing the audio quality from equal BER values. Make your mind up. Shame that you couldn't resist adding "Make your mind up". Are you spiney in disguise? Seriously, you're as exasperating to deal with as him. My interest is in the various things I have described which may affect the *output* of the RXs in *measureable* terms. One of the obvious factors will be how CNR may affect BER I know, and this is exactly what I thought you wanted to do from the very beginning, but it's this statement that I object to: "may have some impact on the assessment of DAB that people keep making/assuming." Exactly what do you mean by that, Jim? Assessment of DAB that people keep making/assuming? Who TF are you? But, of course, I'll just be accused of mis-intepreting what you've said, again, It is not an "accusation" to point out that someone has misunderstood something. Effectively the same thing: http://www.onelook.com/?w=accusation&ls=a noun: an assertion that someone is guilty of a fault or offence The fault you're accusing me of is mis-understanding something. Which I deny. I am afraid you are having an emotional reaction when none is needed. The reason I'm ****ed off here is because you've accused me of mis-understanding something which I haven't mis-understood from day 1, and yet you've just tried to weasel out of admitting what you actually wanted to do. You're patronising and you think you can never be wrong. and your merry band of supporters will raise their hands and say "Yes, Jim, I understand fully what you've said, your use of the English language is perfect, with no hint of ambiguity, and your explanations are possibly the most lucidly-written pieces of text I have ever read in my entire life. In fact, it's a shame I'm male, because I would like to have your children." I can't recall anyone actually responding in that way, TBH. More likely that most sensible people wandered off down to pub ages ago... :-) In one way it might seem quite flattering to think that I have a "merry band of supporters". However I am not entirely sure the idea is accurate. It seems to rather under-regard other people here. Also: If there is a fan club, should I not have a membership badge, or something? Jim, if you want to provide your fan-boys with a badge then that's entirely up to you. But I don't see how that's relevant to this discussion. That said, rather than diverting the discussion to me and a hypothetical "merry band", I'd prefer to focus on the technical issues I have been raising. Don't deflect this away from you. I've answered your technical queries. Although it looks like no results of the kinds of tests I am interested in is available, which is a dissapointment. I've already told you that I'm not aware of any relevant information. FWIW I don't really know why you tend to react in such emotional ways to what I have been writing. BECAUSE YOU HAVE CONTINUALLY ACCUSED ME OF MIS-UNDERSTANDING WHAT YOU WANT TO DO. YOU'VE DONE IT ABOUT 3 TIMES IN THIS POST ALONE. There are far worse things in the real world to get concerned about. Relax. This isn't worth getting yourself upset about. I'll relax when I decide to relax, and that'll be after you've admitted that I've not mis-understood what you want to do you patronising git. -- Steve - www.digitalradiotech.co.uk - Digital Radio News & Info Please sign the petition asking the BBC to provide better audio quality on its radio stations on DAB, Freeview, satellite and cable: http://tinyurl.com/a68e4 |
DAB Performance of different makes?
etillet wrote:
DAB sounds worse than FM wrote: Actually, I did read your posts on Google Groups this morning to see your reaction to being blocked, So you hide someone's posts from your view and then you're so inquisitive to read them you circumvent your own killfile? I think you might do your own sanity a favour (not to mention everyone else's) if you took, say, a 1 month break from usenet... Be quiet. -- Steve - www.digitalradiotech.co.uk - Digital Radio News & Info Please sign the petition asking the BBC to provide better audio quality on its radio stations on DAB, Freeview, satellite and cable: http://tinyurl.com/a68e4 |
DAB Performance of different makes?
Jim Lesurf wrote:
In article , DAB sounds worse than FM wrote: Jim Lesurf wrote: For all I know Classic FM would sound the same if the value was "0" as it does when the value is in the range 2-4. Or it might sound noticably different. Do you know what the "signal error" goes up to? No. Not bothered to experiment much with the specific 'adaptor' as I don't expect much from it in any case, and simply use it for general listening whilst doing things like posting to usenet. :-) In my experience, there's no difference in audio quality from when there's maximum signal quality down to when the bubbling mud actually starts. But is that based on varying the input RF level in a controlled manner? No. And a perception/judgement isn't the type of measurement I am interested in at this point. There you go again, denying what you want to do. You can't admit that you were wrong originally -- a very bad trait, IMO. You're flitting between comparing reception quality and audio quality as it suits you. Get a grip. Can't be sure. I'm just using this as an example as I tend not to listen to Classic FM anyway. But it illuminates the sort of problems I'm curious about. The makers do not provide the necessary info to interpret the numbers. Nor do reviews seem to give any info on this - for the various RXs I've seen. Hence if someone has poor reception conditions, how can they judge before they buy what RXs might - for them - function worse than others? No data to make comparisions and reach decisions. You seem to be flitting between talking about reception problems and audio quality problems. I'm simply accepting that one *may* lead to the other in at least some cases. EXACTLY. And that is EXACTLY what I have been saying all along, and that is EXACTLY what you have been denying ALL ALONG. This is what you said originally that I took offence to: " If it is the case that different DAB RXs give differing outputs when fed with the same DAB signal, then it may have some impact on the assessment of DAB that people keep making/assuming." especially "then it may have some impact on the assessment of DAB that people keep making/assuming" You've even admitted that you wanted to know whether "signal error 3" might degrade teh audio quality compared to "signal error 0". You've admitted it, and you're STILL denying that that is one of the things that you want to test because you think "it may have some impact on the assessment of DAB that people keep making/assuming." -- Steve - www.digitalradiotech.co.uk - Digital Radio News & Info Please sign the petition asking the BBC to provide better audio quality on its radio stations on DAB, Freeview, satellite and cable: http://tinyurl.com/a68e4 |
DAB Performance of different makes?
In article , DAB sounds worse than FM
wrote: [snip] There you go again, denying what you want to do. You can't admit that you were wrong originally -- a very bad trait, IMO. You're flitting between comparing reception quality and audio quality as it suits you. Get a grip. [snip] sigh Having read the above, and some of the other postings by Steve since in this thread, I think I will have to conclude that it would be a waste of effort for me to try again to explain this to him. However, if anyone other than Steve hasn't understood clearly what I have been trying to explain, please say, and I will have another go. My regrets are that an attempt to find info on the topics I was asking about have been submerged by Steve's reactions. Steve: you are clearly able to use whatever 'tone' you like in your postings. By the same token, others can decide it isn't worth talking to you if you respond as exampled above. Slainte, Jim -- Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html |
DAB Performance of different makes?
"DAB sounds worse than FM" wrote in message ... etillet wrote: snip I think you might do your own sanity a favour (not to mention everyone else's) if you took, say, a 1 month break from usenet... Be quiet. Please take you own advice, or are you still going to behave like a rant-boy?... |
DAB Performance of different makes?
DAB sounds worse than FM wrote:
Jim Lesurf wrote: There are far worse things in the real world to get concerned about. Relax. This isn't worth getting yourself upset about. I'll relax when I decide to relax, and that'll be after you've admitted that I've not mis-understood what you want to do you patronising git. Stevie's gone past irritating for me into the realms of the completely ludicrous! I can't for the life of me see how he can so comprehensively and consistently miss the entire point! Neither can I see how Jim could put it more clearly - it's like somehow his words get translated into something different between his news server and Stevie's! Perhaps Steve's got ROT13 turned on :-) -- Nobby |
DAB Performance of different makes?
DAB sounds worse than FM wrote:
etillet wrote: DAB sounds worse than FM wrote: Actually, I did read your posts on Google Groups this morning to see your reaction to being blocked, So you hide someone's posts from your view and then you're so inquisitive to read them you circumvent your own killfile? I think you might do your own sanity a favour (not to mention everyone else's) if you took, say, a 1 month break from usenet... Be quiet. ROTFLMAO!!! Now do as King Stevie says! -- Nobby |
DAB Performance of different makes?
"Nobody Here" wrote in message ... snip Stevie's gone past irritating for me into the realms of the completely ludicrous! I can't for the life of me see how he can so comprehensively and consistently miss the entire point! He doesn't want to understand... |
DAB Performance of different makes?
Nobody Here wrote: DAB sounds worse than FM wrote: Jim Lesurf wrote: There are far worse things in the real world to get concerned about. Relax. This isn't worth getting yourself upset about. I'll relax when I decide to relax, and that'll be after you've admitted that I've not mis-understood what you want to do you patronising git. Stevie's gone past irritating for me into the realms of the completely ludicrous! I can't for the life of me see how he can so comprehensively and consistently miss the entire point! Neither can I see how Jim could put it more clearly - it's like somehow his words get translated into something different between his news server and Stevie's! Perhaps Steve's got ROT13 turned on :-) I *knew* that would get one out of you, Dave "the rave" Plowman and ;;;;Jerry;;;; going. Absolutely knew it. It's quite simple, and it bemuses me how supposedly intelligent people cannot see the error in their ways; Jim wants to test the performance of different DAB receivers to see which perform better than others and, importantly, he wants to know BOTH which perform best under poor signal strength conditions AND whether differences in BER affect the output audio quality. Now, it's the latter that I've been going on about since the start, and that's the thing that Jim has been denying, and yet if you read his posts he actually admits time and again that he does want to test this. But thanks for your ultra-predictable response. Don't worry, I'm not going to make a habit of looking to see if you, Dave the Rave and Jerry with his pacemaker have responded in future. So don't get your hopes up for an argument, there's a good Ozzie. How's it going without The Ashes, BTW? |
DAB Performance of different makes?
Steve said it himself the other day - he's narcissistic. I should
thank him for pointing that out. Here's a web treatise on narcissism, and it does match well with his posts: A narcissistic individual has a basic sense of inferiority although if you listen to him talk you would never realize it. A narcissist presents a false self to the world. Under his inferiority is a preoccupation with fantasies of outstanding achievement, ideal love, and an aimless orientation toward superficial interests. The narcissist uses others to aid him in any tasks he undertakes and will frequently take credit for work which others have done. The narcissistic individual may be more successful at his chosen field of work than some of the other personality disorders. This is because his work can be advantageous to the narcissist especially if it provides narcissistic supply. Lying is an integral part of the narcissist's behavior and all their self-reports are unreliable. His cognition is impaired to the extent that he frequently misinterprets other's speech, actions, and thoughts. He may believe that someone respects or loves him although this is a fantasy which exists only in the mind of the narcissist. Narcissists will over inflate their own accomplishments, are boastful, and pretentious. They frequently will compare themselves to people of great accomplishments and are surprised when others do not agree with them. In fact, it is not unusal for the narcissist to compare himself with God. Although he may attempt to impress others with knowledge and decisiveness, a narcissistic person's information base is often limited to trivia. His ideas are seldom original. He chooses to quote whoever he feels at the time is an authority, however, the narcissist's quotations may not be accurate as to what the chosen authority meant. The narcissist makes his own interpretations to best suit his whim. People other than the narcissist may wonder why he picked that individual as an authority since no true validation may exist the individual is an authority. He also feels that people of high status can only understand him and he often assigns special, gifted, or unique qualities to the people with whom he associates. He will insist that he has the best doctor, lawyer, etc., available, and will assign non-factual accomplishments to that individual to prove the validity of his claims. A narcissistic individual displays beliefs and behaviors that indicate a sense of 'specialness' or 'uniqueness.' He expects favorable treatment from others and wants automatic compliance with his requests. For instance he does not feel he should be made to wait in line and expects to be the center of attention. He is mystified when he does not get what he wants. If an individual disappoints him then he will devalue that person. A narcissist demonstrates a lack of empathy towards others and this causes him to treat others like objects. He does not see others as human beings, but sees them as objects that have no feelings or needs. His sense of entitlement leads to his exploitation of others and this results in little guilt or remorse. A narcissistic injury occurs when someone defeats or criticizes the narcissistic individual. The narcissist may not show it outwardly, but he is haunted by criticisms and defeats. Therefore, the narcissist does have emotions. The narcissist, however, does not relate to his emotions as others do because he represses his emotions so deeply that they play no conscious role in his behavior. But, these repressed emotions unconsciously play a large part in determining his behavior. When a narcissistic injury occurs, the narcissist begins to feel empty, degraded, and humiliated and he is capable of retaliating with narcissistic rage. His reactions constitute disdain or defiant attacks. |
DAB Performance of different makes?
Steve, that's embarrassing! Despite the narcissism, I'd had the
impression that you were stronger willed than that. "I've killfiled them. Now I've really killfiled them. Now I've really really..." |
DAB Performance of different makes?
Mugwump wrote:
Steve, that's embarrassing! Despite the narcissism, I'd had the impression that you were stronger willed than that. I'd say I am *very* strong-willed. Just read some of my posts on this thread for example. ;-) I think looking at people's posts despite killfiling them is a different issue to willpower. I'll let others debate what it is. "I've killfiled them. Now I've really killfiled them. Now I've really really..." All 3 of them *are* killfiled, but my killfile doesn't apply to Google Groups. :-) -- Steve - www.digitalradiotech.co.uk - Digital Radio News & Info Please sign the petition asking the BBC to provide better audio quality on its radio stations on DAB, Freeview, satellite and cable: http://tinyurl.com/a68e4 |
DAB Performance of different makes?
On Mon, 31 Oct 2005 16:31:27 GMT, "DAB sounds worse than FM"
wrote: Save the sanctimonious lecture for someone else. In a magazine or on my website I will write in a different manner to how I write on here, because this is Usenet. This is a serious question so please treat it as such. I adopt the same written tone as I do when speaking face-to-face or writing a letter. Why should writing for Usenet mean that you can use a different written tone to the tone you use elsewhere? -- Alan White Twenty-eight miles NW of Glasgow, overlooking Loch Goil and Loch Long in Argyll, Scotland. Web cam and weather:- http://www.windycroft.gt-britain.co....her/kabcam.htm Some walks and treks:- http://www.windycroft.gt-britain.co.uk/walks/ |
DAB Performance of different makes?
Alan White wrote:
On Mon, 31 Oct 2005 16:31:27 GMT, "DAB sounds worse than FM" wrote: Save the sanctimonious lecture for someone else. In a magazine or on my website I will write in a different manner to how I write on here, because this is Usenet. This is a serious question so please treat it as such. I adopt the same written tone as I do when speaking face-to-face or writing a letter. Why should writing for Usenet mean that you can use a different written tone to the tone you use elsewhere? Why? Because this isn't face-to-face communication. Read a few threads and see how many examples of strong language and rudeness there is that you wouldn't expect people to use in face-to-face communication; there's lots. Also, why am I the one singled out by you? Are you suggesting that @@@@[email protected]@@@ or Dave Plowman would call me a moron, idiot or cretin to my face? -- Steve - www.digitalradiotech.co.uk - Digital Radio News & Info Please sign the petition asking the BBC to provide better audio quality on its radio stations on DAB, Freeview, satellite and cable: http://tinyurl.com/a68e4 |
DAB Performance of different makes?
On Mon, 31 Oct 2005 19:53:13 GMT, "DAB sounds worse than FM"
wrote: Also, why am I the one singled out by you? ....because you happened to mention it. Are you suggesting that @@@@[email protected]@@@ or Dave Plowman would call me a moron, idiot or cretin to my face? I'm afraid I can't speak for them but, if I thought it was warranted, I would. -- Alan White Twenty-eight miles NW of Glasgow, overlooking Loch Goil and Loch Long in Argyll, Scotland. Web cam and weather:- http://www.windycroft.gt-britain.co....her/kabcam.htm Some walks and treks:- http://www.windycroft.gt-britain.co.uk/walks/ |
DAB Performance of different makes?
Alan White wrote:
On Mon, 31 Oct 2005 19:53:13 GMT, "DAB sounds worse than FM" wrote: Are you suggesting that @@@@[email protected]@@@ or Dave Plowman would call me a moron, idiot or cretin to my face? I'm afraid I can't speak for them but, if I thought it was warranted, I would. Really? So how many non-family members have you called "a cretin" or "a moron" in a non-joking manner? And what proportion of the people that you called "a cretin" or "a moron" punched you in the face after you'd said what you'd said? Basically, face-to-face communication very, very rarely gets to the point where people do start calling someone else a moron or a cretin. Basically, the "less removed" you are from communicating with someone in real-time and/or face-to-face the more likely you are to be polite to the other person. That is: you're the most likely to be polite face-to-face if someone does something that annoys you you're less likely to be polite on the phone if someone does something that annoys you you're even less likely to be polite in text communication if someone does something that annoys you It's just the way it is. I tell you what, I believe the operating system advocacy newsgroups are, how shall I say it, a bit lively, so go and read one of them to see how common arguing is on Usenet. The thing with me, Jerry and Plowman is that we're advocating opposite things: Plowman and Jezz are advocating DAB, and I'm of the opposite view. -- Steve - www.digitalradiotech.co.uk - Digital Radio News & Info Please sign the petition asking the BBC to provide better audio quality on its radio stations on DAB, Freeview, satellite and cable: http://tinyurl.com/a68e4 |
DAB Performance of different makes?
"DAB sounds worse than FM" wrote in message ... snip The thing with me, Jerry and Plowman is that we're advocating opposite things: Plowman and Jezz are advocating DAB, and I'm of the opposite view. You still don't get it, do you... I can't speak for Dave, but I have never advocated DAB, although I can understand why some people use it in place of an analogue radio service and I can understand why the realities of the economics of the commercial world means DAB is carrying so many services. |
DAB Performance of different makes?
On Mon, 31 Oct 2005 20:29:05 GMT, "DAB sounds worse than FM"
wrote: Alan White wrote: On Mon, 31 Oct 2005 19:53:13 GMT, "DAB sounds worse than FM" wrote: Are you suggesting that @@@@[email protected]@@@ or Dave Plowman would call me a moron, idiot or cretin to my face? I'm afraid I can't speak for them but, if I thought it was warranted, I would. Really? So how many non-family members have you called "a cretin" or "a moron" in a non-joking manner? None, because I've never met anybody who warranted it, I try to avoid confrontation and I'm fairly easy going. ...you're the most likely to be polite face-to-face if someone does something that annoys you you're less likely to be polite on the phone if someone does something that annoys you you're even less likely to be polite in text communication if someone does something that annoys you It's just the way it is. ....for you. Thank you, that was very illuminating. -- Alan White Twenty-eight miles NW of Glasgow, overlooking Loch Goil and Loch Long in Argyll, Scotland. Web cam and weather:- http://www.windycroft.gt-britain.co....her/kabcam.htm Some walks and treks:- http://www.windycroft.gt-britain.co.uk/walks/ |
DAB Performance of different makes?
Alan White wrote:
On Mon, 31 Oct 2005 20:29:05 GMT, "DAB sounds worse than FM" wrote: Alan White wrote: On Mon, 31 Oct 2005 19:53:13 GMT, "DAB sounds worse than FM" wrote: Are you suggesting that @@@@[email protected]@@@ or Dave Plowman would call me a moron, idiot or cretin to my face? I'm afraid I can't speak for them but, if I thought it was warranted, I would. Really? So how many non-family members have you called "a cretin" or "a moron" in a non-joking manner? None, because I've never met anybody who warranted it, I try to avoid confrontation and I'm fairly easy going. ...you're the most likely to be polite face-to-face if someone does something that annoys you you're less likely to be polite on the phone if someone does something that annoys you you're even less likely to be polite in text communication if someone does something that annoys you It's just the way it is. ...for you. And for a bloody high proportion of people that post on Usenet. Thank you, that was very illuminating. Actually, that kind of comment is a good example of why lots of arguments happen on Usenet as well. In the context, it's possible to read that as being genuninely thankful, or very sarcastic. IMO a lot of arguments would be avoided if you could hear the tone of voice that the other person would have liked to convey. But you can't convey it, and there will always be mis-interpretations of what's the poster really wants to say, and there will always be arguments. It's just the way it is. -- Steve - www.digitalradiotech.co.uk - Digital Radio News & Info Please sign the petition asking the BBC to provide better audio quality on its radio stations on DAB, Freeview, satellite and cable: http://tinyurl.com/a68e4 |
DAB Performance of different makes?
|
DAB Performance of different makes?
DAB sounds worse than FM wrote:
Alan White wrote: On Mon, 31 Oct 2005 16:31:27 GMT, "DAB sounds worse than FM" wrote: Save the sanctimonious lecture for someone else. In a magazine or on my website I will write in a different manner to how I write on here, because this is Usenet. This is a serious question so please treat it as such. I adopt the same written tone as I do when speaking face-to-face or writing a letter. Why should writing for Usenet mean that you can use a different written tone to the tone you use elsewhere? Why? Because this isn't face-to-face communication. Read a few threads and see how many examples of strong language and rudeness there is that you wouldn't expect people to use in face-to-face communication; there's lots. Also, why am I the one singled out by you? Are you suggesting that @@@@[email protected]@@@ or Dave Plowman would call me a moron, idiot or cretin to my face? I would. I mightn't have, but I would now! -- Nobby |
DAB Performance of different makes?
DAB sounds worse than FM wrote:
Alan White wrote: On Mon, 31 Oct 2005 20:29:05 GMT, "DAB sounds worse than FM" wrote: Alan White wrote: On Mon, 31 Oct 2005 19:53:13 GMT, "DAB sounds worse than FM" wrote: Are you suggesting that @@@@[email protected]@@@ or Dave Plowman would call me a moron, idiot or cretin to my face? I'm afraid I can't speak for them but, if I thought it was warranted, I would. Really? So how many non-family members have you called "a cretin" or "a moron" in a non-joking manner? None, because I've never met anybody who warranted it, I try to avoid confrontation and I'm fairly easy going. ...you're the most likely to be polite face-to-face if someone does something that annoys you you're less likely to be polite on the phone if someone does something that annoys you you're even less likely to be polite in text communication if someone does something that annoys you It's just the way it is. ...for you. And for a bloody high proportion of people that post on Usenet. Thank you, that was very illuminating. Actually, that kind of comment is a good example of why lots of arguments happen on Usenet as well. In the context, it's possible to read that as being genuninely thankful, or very sarcastic. Dunno, dope, it was pretty clear to me. But then that's the root of your problem, isn't it? Comprehension. I can write directly to you, now I *know* that you cant resist reading it anyway. -- Nobby |
| All times are GMT +1. The time now is 06:28 AM. |
Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.
HomeCinemaBanter.com