QUESTIONS: S/PDIF, 5.1, CPU utilization, etc.

[DJ]

In general, I'm pretty knowledgeable about this stuff, but on this issue,
I'm stuck.

Question 1: When referring to "digital" speakers, it simply means that the
speakers have a S/PDIF input and can handle the Dolby Digital (and DTS or
whatever else) decoding themselves. (Usually they have a break-out box for
this.) True/False?

Question 2: I have the RealTek ALC650 on-board audio on my computer. I can
get a NON-digital 5.1 speaker package and hook it up via the 3 mini-jacks
and get full 5.1 surround sound. The decoding would be handled by the
ALC650 chip, the signals to the speakers would be analog, and I would take a
CPU utilization hit for it. True/False?

Question 3: If I get a digital 5.1 speaker package and hook them up via the
S/PDIF output, then it bypasses the ALC650 in terms of 5.1 decoding and all
of that is done by the speaker package. Do I still incur the CPU
performance hit? Does the audio still come out of the mini-jacks? If I do
and it does, is there any way to stop it? Does the ALC650 do any work to
the signal coming out of the S/PDIF connector? If I disable on-board sound,
does signal still come out of the S/PDIF connector?

Question 4: If I buy an Audigy 2 with all the on-board 5.1 (or 6.1 or 7.1)
decoding built in, and then used the S/PDIF output, was there any point to
buying the audio card in the first place?

Thanks in advance... I've spent a full day searching online for these
answers to no avail.

-DJ

[Arny Krueger]

"DJ" > wrote in message


> In general, I'm pretty knowledgeable about this stuff, but on this
> issue, I'm stuck.

> Question 1: When referring to "digital" speakers, it simply means
> that the speakers have a S/PDIF input and can handle the Dolby
> Digital (and DTS or whatever else) decoding themselves. (Usually
> they have a break-out box for this.) True/False?

Generally true. If there's a digital input, then the digital/analog decoding
is done in the speakers because there is noplace else it could happen and be
relevant.

> Question 2: I have the RealTek ALC650 on-board audio on my computer.
> I can get a NON-digital 5.1 speaker package and hook it up via the 3
> mini-jacks and get full 5.1 surround sound. The decoding would be
> handled by the ALC650 chip, the signals to the speakers would be
> analog, and I would take a CPU utilization hit for it. True/False?

True.

> Question 3: If I get a digital 5.1 speaker package and hook them up
> via the S/PDIF output, then it bypasses the ALC650 in terms of 5.1
> decoding and all of that is done by the speaker package. Do I still
> incur the CPU performance hit?

It depends on how the application software is written. Most DVD player
software operates in either/or mode. Any software that activated the analog
and digital sound cards concurrently would still incur the CPU utilization
hit.

> Does the audio still come out of the
> mini-jacks?

Up to the application software and/or the user.

> If I do and it does, is there any way to stop it? Does
> the ALC650 do any work to the signal coming out of the S/PDIF
> connector?

Minimal.

> If I disable on-board sound, does signal still come out
> of the S/PDIF connector?

Test it yourself and see.

> Question 4: If I buy an Audigy 2 with all the on-board 5.1 (or 6.1 or
> 7.1) decoding built in, and then used the S/PDIF output, was there
> any point to buying the audio card in the first place?

I don't see any.

> Thanks in advance... I've spent a full day searching online for these
> answers to no avail.

[DJ]

Thank you so much for your replies. You pretty much confirmed everything I
thought/feared.

Just to follow up... I don't see any way (in the drivers) to stop the audio
from being processed by the ALC650 while still letting the bits go through
the S/PDIF port. If certain software applications provide that, cool, but I
don't see it in any that I use. I'm primarily looking at games.

Also, as you suggested, I confirmed for myself that if I turn off on-board
audio in the BIOS, the S/PDIF link goes dead as well. (It's optical, so it
was pretty easy to tell. ;-)

Thanks again!
-DJ

"Arny Krueger" > wrote in message
...
> "DJ" > wrote in message
>
>
> > In general, I'm pretty knowledgeable about this stuff, but on this
> > issue, I'm stuck.
>
> > Question 1: When referring to "digital" speakers, it simply means
> > that the speakers have a S/PDIF input and can handle the Dolby
> > Digital (and DTS or whatever else) decoding themselves. (Usually
> > they have a break-out box for this.) True/False?
>
> Generally true. If there's a digital input, then the digital/analog
decoding
> is done in the speakers because there is noplace else it could happen and
be
> relevant.
>
> > Question 2: I have the RealTek ALC650 on-board audio on my computer.
> > I can get a NON-digital 5.1 speaker package and hook it up via the 3
> > mini-jacks and get full 5.1 surround sound. The decoding would be
> > handled by the ALC650 chip, the signals to the speakers would be
> > analog, and I would take a CPU utilization hit for it. True/False?
>
> True.
>
> > Question 3: If I get a digital 5.1 speaker package and hook them up
> > via the S/PDIF output, then it bypasses the ALC650 in terms of 5.1
> > decoding and all of that is done by the speaker package. Do I still
> > incur the CPU performance hit?
>
> It depends on how the application software is written. Most DVD player
> software operates in either/or mode. Any software that activated the
analog
> and digital sound cards concurrently would still incur the CPU utilization
> hit.
>
> > Does the audio still come out of the
> > mini-jacks?
>
> Up to the application software and/or the user.
>
> > If I do and it does, is there any way to stop it? Does
> > the ALC650 do any work to the signal coming out of the S/PDIF
> > connector?
>
> Minimal.
>
> > If I disable on-board sound, does signal still come out
> > of the S/PDIF connector?
>
> Test it yourself and see.
>
> > Question 4: If I buy an Audigy 2 with all the on-board 5.1 (or 6.1 or
> > 7.1) decoding built in, and then used the S/PDIF output, was there
> > any point to buying the audio card in the first place?
>
> I don't see any.
>
> > Thanks in advance... I've spent a full day searching online for these
> > answers to no avail.
>
>
>

[Emmanuel Allaud]

On Mon, 29 Sep 2003, DJ wrote:

> Thank you so much for your replies. You pretty much confirmed everything I
> thought/feared.
>
> Just to follow up... I don't see any way (in the drivers) to stop the audio
> from being processed by the ALC650 while still letting the bits go through
> the S/PDIF port. If certain software applications provide that, cool, but I
> don't see it in any that I use. I'm primarily looking at games.

Games are another issue : the sound is CREATED on-the-fly, so here the
sound card is more important for performance because the sound has to be
altered to be heard as coming from whereever someone is fragging you ;-)
And in that case I don't think you can use the S/PDIF digital out to plug
it to a external receiver (only the nforce2 chipset can encode the 3d
sound in Dolby to ouput it digitally).

Bye
Manu