Home cinema - HDTVs and audio

HomeCinemaBanter (http://www.homecinemabanter.com/index.php)

- UK digital tv (http://www.homecinemabanter.com/forumdisplay.php?f=5)

- - HDTVs and audio (http://www.homecinemabanter.com/showthread.php?t=73978)

On Wed, 01 Jan 2014 14:58:02 +0000 (GMT), Jim Lesurf
wrote:
3) Does that normally then bypass any 'volume control' of the TV
set? Or is
this user-choosable, or what?

My TV and Audio system - both Samsung - have integrated control
through the remote (Samsung's implementation of HDMI-CEC). When the
Home Theatre is on, the TV remote audio buttons control it's volume
and TV speakers are off.

CEC isn't guaranteed to work if devices are from different brands.
On my set-up, the HT has to be switched on manually (or via TV
remote) - it's not automatic with TV start-up.

It would be convenient from my POV is the TV acted simply as a 'pass
though' for the audio from external sources - e.g. DVD player. So
ensured
lip-synch by otherwise allowed the audio samples to be 'as from the
source'
without any sounds from the TVs speakers. But is the norm? Or is
there a
problem here?

What you need to check is whether the TV will pass through
multi-channel audio. My model down-mixes to stereo, but this was
changed in later ones. I believe there was some licensing issue
involved.
,
You will get more detailed answers from AV web forums. There will
likely find threads dedicated to a candidate model.

In article , Andy
Burns
wrote:
Jim Lesurf wrote:

Using the TVs 'volume control' something I'd tend to avoid if possible
as I have no idea how well it can scale the values.

My TV just seems to send "+" and "-" commands to the amp rather than
absolute values, my amp is set for a 0-100 scale with 0.5 unit steps
which is finer than the TV's inbuilt volume control (0 to 63 I think)
the amp has the option of using a dB scale but my brain doesn't
naturally use logs.

FWIW human response to how loud sounds are tends to be more like a 'log'
variation. So values in dB seem fairly natural to me. Indeed, I regret that
many modern hifi amps lack precise steps in a quasi-log sequence on their
mechanical volume controls.

My concern about scaling, though, isn't the law of the adjustement. But
questions like how well the *sample values* are scaled. e.g. the need to
dither or noise shape to avoid adding distortion unless it is 24bit (or
more).

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

In article ,
Jim Lesurf wrote:
At long last I've decided to take the plunge and buy an HDTV 'Freeview'
set. Almost certainly an LED Panasonic of modest size. I'd welcome some
answers to a few pretty basic questions, mainly wrt the audio side of
operations.

1) Is it standard for such sets to accept audio in via HDMI and then copy
that out via an SPDIF coax/optical outlet for connection to a decent
external DAC?

More common is optical out.

If the answer to (1) is 'yes':

2) Is it normal to then be able to mute the TV's own speakers so you just
can use a hifi and the external DAC for the audio?

Yes. There is often a menu setting that allows you to turn off the
internal speakers.

3) Does that normally then bypass any 'volume control' of the TV set? Or
is this user-choosable, or what?

Again yes - or could be either. The mute control may still work, though.
Which can be handy.

4) Does HDMI ensure audio-video synch? Either from the TV's digital
output, or by telling the HDMI source and allowing a digital spdif
output from that to be delayed to match? Or?

Seems OK here.

It would be convenient from my POV is the TV acted simply as a 'pass
though' for the audio from external sources - e.g. DVD player. So
ensured lip-synch by otherwise allowed the audio samples to be 'as from
the source' without any sounds from the TVs speakers. But is the norm?
Or is there a problem here?

Any audio delay is normally applied to the output from the TV, so if you
route your DVD etc through it all should be fine. The snags arise if you
feed the audio direct to an external amp.

Also:

Are middle-of-the range panasonics likely to have 3 HDMI sockets?

Should have, but check. Some bargains may be old models with fewer inputs
than the current norm. Mine has three and an additional HDMI for computer
- I'm not quite sure what is different with this one, yet. I'm wondering
if it allows two way 'traffic'.

Allow no 'overscan' so a 1:1 scaling of HD sources?

Most give a bewildering variety of choices. Hopefully with the correct one
in there somewhere.

I'll ask about such things in the shop. But some comments here to clarify
what I should be able to expect would be helpful.

If you look on the Curries website, you'll find basic information about
number of inputs etc. And whether it has an HD FreeView tuner - not all
smaller sets do, although may claim to be full HD.

In my experience you can generally forget asking a shop assistant about
such things. Unless you have a decent independant retailer - but be
prepared to pay rather more for the same set than you might otherwise.

Perhaps if you find the model that seems to suit you online and give its
number, someone with it could give more specific answers.

--
*(on a baby-size shirt) "Party -- my crib -- two a.m

Dave Plowman London SW
To e-mail, change noise into sound.

On 02/01/2014 13:01, Andy Furniss wrote:

I always thought the crappy edges were scaler artifacts rather than
mpeg/bitrate related - but then I could be wrong.

They mostly appear to be blanking errors, which by rights shouldn't
be there on a completely end to end digital system.

One problem however are digital effects units, where the background
(next event) image is sometimes one pixel (each side) wider and one
pixel higher (top and bottom) than the foreground image.

--
Mark
Please replace invalid and invalid with gmx and net to reply.

Mark Carver wrote:
On 02/01/2014 13:01, Andy Furniss wrote:

I always thought the crappy edges were scaler artifacts rather
than mpeg/bitrate related - but then I could be wrong.

They mostly appear to be blanking errors, which by rights shouldn't
be there on a completely end to end digital system.

One problem however are digital effects units, where the background
(next event) image is sometimes one pixel (each side) wider and one
pixel higher (top and bottom) than the foreground image.

Ahh, something different then. I was thinking scaler artifacts relying
on vague memories or reading something, probably by Clive Poynton, which
said multi tap scaler artifacts were expected on edges.

I don't actually watch much TV, and TBH they aren't that noticable
anyway - slightly more annoying is why do the BBC scale down to 704 and
put it in 720 - why not just to broadcast 704 and loose the black bars?

In article , Jim
wrote:
On Wed, 01 Jan 2014 14:58:02 +0000 (GMT), Jim Lesurf
wrote:

What you need to check is whether the TV will pass through
multi-channel audio. My model down-mixes to stereo, but this was
changed in later ones. I believe there was some licensing issue
involved. , You will get more detailed answers from AV web forums.
There will likely find threads dedicated to a candidate model.

I'm only really interested in stereo for audio. The room isn't big enough
for two more Quad ESLs anyway! 8-] So now I always set sources to output
stereo LPCM, not bitreams.

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

On 01/01/2014 14:58, Jim Lesurf wrote:
At long last I've decided to take the plunge and buy an HDTV 'Freeview'
set. Almost certainly an LED Panasonic of modest size. I'd welcome some
answers to a few pretty basic questions, mainly wrt the audio side of
operations.

1) Is it standard for such sets to accept audio in via HDMI and then copy
that out via an SPDIF coax/optical outlet for connection to a decent
external DAC?

My Samsung TV does this

If the answer to (1) is 'yes':

2) Is it normal to then be able to mute the TV's own speakers so you just
can use a hifi and the external DAC for the audio?

If I mute the TV sound then there is an icon on the screen. Turning down
the volume works fine

3) Does that normally then bypass any 'volume control' of the TV set? Or is
this user-choosable, or what?

In my case the SPDIF output volume is determined by the HDMI input volume.

4) Does HDMI ensure audio-video synch? Either from the TV's digital output,
or by telling the HDMI source and allowing a digital spdif output from that
to be delayed to match? Or?

No, my TV allows the sync to be adjusted. Unfortunately the TV is quite
good at forgetting what the setting should be. So I change the delay,
and then put it back to where it was and the sound is then in sync

It would be convenient from my POV is the TV acted simply as a 'pass
though' for the audio from external sources - e.g. DVD player. So ensured
lip-synch by otherwise allowed the audio samples to be 'as from the source'
without any sounds from the TVs speakers. But is the norm? Or is there a
problem here?

My TV converts the analogue signal from a scart socket to digital and
outputs it via the SPDIF port (likely it also did the same for analogue
TV - but those days are gone)

--
Michael Chare

Jim Lesurf wrote:

Andy Burns wrote:

My TV just seems to send "+" and "-" commands to the amp rather
than absolute values [...] the amp has the option of using a dB
scale but my brain doesn't naturally use logs.

FWIW human response to how loud sounds are tends to be more like a 'log'
variation. So values in dB seem fairly natural to me.

Oh, I'm aware that hearing works in a log fashion, but that doesn't mean
I can glance at a display on the other side of the room reading -33.5dB
and instinctively know whether that means blaring or quiet :-)

In article , Andy
Burns
wrote:
Jim Lesurf wrote:

Andy Burns wrote:

My TV just seems to send "+" and "-" commands to the amp rather than
absolute values [...] the amp has the option of using a dB scale but
my brain doesn't naturally use logs.

FWIW human response to how loud sounds are tends to be more like a
'log' variation. So values in dB seem fairly natural to me.

Oh, I'm aware that hearing works in a log fashion, but that doesn't mean
I can glance at a display on the other side of the room reading -33.5dB
and instinctively know whether that means blaring or quiet :-)

Hardly surprising given that the mean level for pop/rock music may well be
20- 30dB higher than a lot of classical music! So it'll obvious depend on
what you're feeding into the system. :-)

FWIW Although the sources have gain controls I use the analogue volume
control on the preamps. (modified quad 34s) Typically I usually have this
set about 20dB higher for classical music from R3 or my own files than
rock/pop CDs.

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

In article , Michael
Chare [email protected] wrote:
On 01/01/2014 14:58, Jim Lesurf wrote:

2) Is it normal to then be able to mute the TV's own speakers so you
just can use a hifi and the external DAC for the audio?

If I mute the TV sound then there is an icon on the screen. Turning down
the volume works fine

Do that with our existing CRT set. Perhaps a sign of the poor regard TV
builders have for audio is that you can still hear *hiss* from the TV
speakers if you have your head near to them with no audio playing.
Ludicrous for modern power amps after a volume control to do that.

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html