Correct terminology?

Slightly confused with audio terminology when it comes to connections and
hoping someone could help me out. Here's a list of all the terms I can
think of:

1) Stereo headphone jack
2) Phono (L + R channel) ... same as RCA??
3) Component
4) Composite
5) Digital Coax
6) Digital Optical


Now it's particularly 2, 3 and 4 that confuse me - are they all the same
thing apart from component? Do some of them use the same connectors but
different signal processing?


Also, with respect to digital vs. analogue - what difference does it make
and why? If you have a DVD player, does it output digital sound? Is that
before or after (or unrelated!) the Dolby decoding? If you're hooking it up
to a 5.1 speaker set, which has its own Dolby decoder, is that relevant to
whether or not the output from the DVD player is digital or analogue? What
happens if the signal is decoded twice (ie. at each end)? Does it matter?
Can it be prevented at either end if it does?


Happy to be pointed to a FAQ somewhere, but most of what I've read so far
from Googling around gets very technical without really answering the
question and just gets into the physics of sound and metallurgy for cabling!
Any help much appreciated




a

"al" wrote in message
. ..
Slightly confused with audio terminology when it comes to connections and
hoping someone could help me out. Here's a list of all the terms I can
think of:

1) Stereo headphone jack
2) Phono (L + R channel) ... same as RCA??
3) Component
4) Composite
5) Digital Coax
6) Digital Optical


OK, finally found a resource on this and I think I get it now.
RCA/composite is the basic yellow for video and L+R stereo sound. Component
is a similar lead, but just one for both video and sound. S-Video is just
video and commonly paired with RCA twin connectors for sound.

Presuming that's right ... where does SCART fit it!?


Also, with respect to digital vs. analogue - what difference does it make
and why? If you have a DVD player, does it output digital sound? Is that
before or after (or unrelated!) the Dolby decoding? If you're hooking it
up to a 5.1 speaker set, which has its own Dolby decoder, is that relevant
to whether or not the output from the DVD player is digital or analogue?
What happens if the signal is decoded twice (ie. at each end)? Does it
matter? Can it be prevented at either end if it does?


Still don't quite get this - the articles I read whitter on about home
cinema systems, which is not what I have. I have a set of 5.1 speakers with
amp/decoder to accept the inputs (either coax/SPDIF) which can handle
ProLogic II/THX/DTS decoding. How does it work with the DVD in terms of
what decodes what?






a

al wrote:
Slightly confused with audio terminology when it comes to connections and
hoping someone could help me out. Here's a list of all the terms I can
think of:

1) Stereo headphone jack

Audio output designed to drive headphones (impedence = about 32 ohms)
to reasonable listening levels.

2) Phono (L + R channel) ... same as RCA??

Phono, AKA RCA, sockets are cheap and hence used to carry pretty much
anything these days.

L+R phono outputs - audio output designed to drive line input on
amplifier (or anything with input, e.g. soundcard) (impedence = about
14 kilo-ohms)

3) Component

A set of 3 signals which make up a video signal, i.e. carry a picture
from your dvd player to your tv.
Component can mean RGB (red green blue), or Y Pb Pr. The second one is
just a mathematical manipulation of the first one, which has some
advantages sometimes, best not worry about it though...

4) Composite

A single signal which carries a tv picture. The separate colour
signals are combined electroncally. This means the quality is reduced.
This is how analogue tv is delivered.
VHS recorders record a composite signal.

5) Digital Coax

AKA SPDIF (sony philips digital interface) carries a digitally encoded
audio signal. E.g. spdif output of cd player carries exactly the same
digits it decoded off the cd.

6) Digital Optical

AKA TosLink (Toshiba Link ?) exactly the same signal as SPDIF above,
but sent down an optical fibre using a red LED.

Now it's particularly 2, 3 and 4 that confuse me - are they all the same
thing apart from component?

I think you've got your numbers confused.

Do some of them use the same connectors but
different signal processing?

Lots of things use the same connectors. Sony minidiscs even use
minijacks with optical fibre in.

Also, with respect to digital vs. analogue - what difference does it make and why? If you have a DVD player, does it output digital sound?

Through the digital outputs, yes, through the analogue ones, no! Don't
worry, you can't connect a digital output to an analogue input, or vice
versa, it just won't work.

Is that
before or after (or unrelated!) the Dolby decoding?

There's several different kinds of dolby decoding. To simplify for the
kind of kit I think you're talking about:

If your speaker set has a digital (5.1, AC3) input, connect that to the
digital output of your DVD player.
If it has 6 individual inputs, connect them to the analogue surround
outputs on the DVD player.

What
happens if the signal is decoded twice (ie. at each end)?

Once it's decoded it's six separate channels, that's six separate
connectors (or maybe 3 digital ones). There's almost no way you could
then decode it again.

The closest you could come would be putting some of the channels
through an old dolby pro-logic decoder, which creates 4 channels (left,
right, centre and surround) from 2 analogue channels. This might have
odd effects.
If you want surround with films on tv or vhs, you should check whether
your kit can handle pro-logic though.

Does it matter?
Can it be prevented at either end if it does?

I think you worry too much ;o)

Alex

al wrote:

Component
is a similar lead, but just one for both video and sound.

NOOOOOOOOO!

Presuming that's right ... where does SCART fit it!?

SCART carries composite video and analogue stereo sound in both
directions (i.e. input and output).
It can also carry component RGB video (much better) or s-video
(slightly better) but only one at the same time, and in one direction
only.
It carries a switching signal to tell TVs (mainly) to switch to the
scart input, and also when to switch between 16:9 widescreen and 4:3
normal.


Still don't quite get this - the articles I read whitter on about home
cinema systems, which is not what I have. I have a set of 5.1 speakers with
amp/decoder to accept the inputs (either coax/SPDIF) which can handle
ProLogic II/THX/DTS decoding. How does it work with the DVD in terms of
what decodes what?

The speakers are doing the decoding, the DVD player is just sending
them the digital audio stream it reads off the DVD. ProLogic
II/THX/DTS are slightly different signals, but if your speakers can
deal with all of them then there's no need to worry, that covers all
the audio standards used for video DVDs.

Alex

"Alex Bird" wrote in message
oups.com...
al wrote:



Still don't quite get this - the articles I read whitter on about home
cinema systems, which is not what I have. I have a set of 5.1 speakers
with
amp/decoder to accept the inputs (either coax/SPDIF) which can handle
ProLogic II/THX/DTS decoding. How does it work with the DVD in terms of
what decodes what?

The speakers are doing the decoding, the DVD player is just sending
them the digital audio stream it reads off the DVD. ProLogic
II/THX/DTS are slightly different signals, but if your speakers can
deal with all of them then there's no need to worry, that covers all
the audio standards used for video DVDs.

There's no such thing as THX encoding for home cinema. THX is the title of
George Lucas minimum specification for the quality of THeatre equipment
which he will alow to show his movies on.



Alex

"Agamemnon" wrote in message
...

There's no such thing as THX encoding for home cinema. THX is the title of
George Lucas minimum specification for the quality of THeatre equipment
which he will alow to show his movies on.

Yes there is. THX uses a frequency equalisation curve which is optimised for
theatres but not is so hot in a domestic living room. Also THX stands for
Thomas Holden eXperiment, nothing to do with THeatre.

(kim)

"kim" wrote in message
...
"Agamemnon" wrote in message
...

There's no such thing as THX encoding for home cinema. THX is the title
of
George Lucas minimum specification for the quality of THeatre equipment
which he will alow to show his movies on.

Yes there is. THX uses a frequency equalisation curve which is optimised
for
theatres but not is so hot in a domestic living room. Also THX stands for

I am not aware of THX being used on DVD's since they do not require
equalisation because they are digital.

Thomas Holden eXperiment, nothing to do with THeatre.


Actually it was the name of George Lucas first movie THX 1138

(kim)

"Alex Bird" wrote in message
oups.com...

Presuming that's right ... where does SCART fit it!?

SCART carries composite video and analogue stereo sound in both
directions (i.e. input and output).
It can also carry component RGB video (much better) or s-video
(slightly better) but only one at the same time, and in one direction
only.
It carries a switching signal to tell TVs (mainly) to switch to the
scart input, and also when to switch between 16:9 widescreen and 4:3
normal.


Thanks for the replies. OK .. so if SCART can carry either composite or
component video signals .... does that depend on the cable, or merely the
type of SCART connection at both ends (ie. on the DVD and the TV)? SCART
sounds like the most convenient solution for connecting the two because of
the switching ability, but will it be a lower quality connection than using
component video leads between the two (assuming there is an RGB SCART out/in
at both ends)?

Where does one normally output to ones surround speakers from, DVD or TV?
From DVD sounds logical in terms of getting exactly the sounds that is on
the DVD to the disk, but will I be able to direct my normal TV sound through
there even when the DVD player is off? Through the TV sounds better for the
latter, but wouldn't it loose the digital signal if it had to go through RCA
leads first to get to the TV before being output to the speakers over coax?
I'm thinking the only time the TV would have proper digital sound is if it
were a IDTV? As a further confusion, I have no idea how to get the best
sound from the Telewest Pace STB either (which claims to be digital TV ..
not sure what sound benefits come from that though)!





a

al wrote:

Thanks for the replies. OK .. so if SCART can carry either composite or
component video signals .... does that depend on the cable, or merely the
type of SCART connection at both ends (ie. on the DVD and the TV)?

See http://en.wikipedia.org/wiki/SCART

SCART has pins for R, G, B and composite, so it can carry both
simultaneously. Obviously, you'll only get RGB if the source is
supplying it and the display is picking it up.

SCART
sounds like the most convenient solution for connecting the two because of
the switching ability, but will it be a lower quality connection than using
component video leads between the two (assuming there is an RGB SCART out/in
at both ends)?

It's easier to do really good component leads than SCART because of the
construction (three simple single leads instead of many crammed into the
tiny shell. You can get RGB-only SCART cables which do away with the
audio and composite.

Component and RGB connections go through different circuitry at each
end, so the quality will differ. Mathematically, one can be converted to
the other perfectly, but in reality, there will always be differences.
Either will be very good and much better than composite, though.

--
Mark.
http://tranchant.plus.com/

"Agamemnon" wrote in message
...

"kim" wrote in message
...
"Agamemnon" wrote in message
...

There's no such thing as THX encoding for home cinema. THX is the title
of
George Lucas minimum specification for the quality of THeatre equipment
which he will alow to show his movies on.

Yes there is. THX uses a frequency equalisation curve which is optimised
for
theatres but not is so hot in a domestic living room. Also THX stands for

I am not aware of THX being used on DVD's since they do not require
equalisation because they are digital.

All THX home recordings whether analogue or digital use 3db of pre-emphasis
for frequencies above 2khz. This is not normally noticeable due to
absorbtion by room furniture. THX decoders include a defeat switch which
de-emphasises the signal but is not strictly necessary. THX decoders also
extract separate left-right surround from Dolby Pro-Logic recordings.


Thomas Holden eXperiment, nothing to do with THeatre.


Actually it was the name of George Lucas first movie THX 1138

Which has nothing to do with the name chosen for the certification program,
or so Lucas claims.

(kim)