More than one audio codec on a PC mobo

[Alexander Y. Sure]

On 26/02/14 06:01, Joerg wrote:

Folks,

The AC97 standard describes only up to four sound chips operated
simultaneously, on page 21:

ftp://download.intel.com/support/motherboards/desktop/sb/ac97_r23.pdf

What if one would like to connect, say, 20 of them and all are supposed
to run nicely synchronous? Like in a digital mixer board for music.

What you want to look into is not AC'97 but the more modern Intel High
Definition Audio (HDA)specification. It supports 500 bit slots for input
(~15 32 bit channels) multi codec streams and synchronization.

http://tinyurl.com/ln2oew8

HDA codecs are very cheap. Realtek ALC889 go for ~0.6$ in single digit
quantities.

http://tinyurl.com/kcxzcs2

The interface would be predominantly a FIFO with a few ornaments.

Regards
Werner Dahn

 

[Michael A. Terrell]

krw@attt.bizz wrote:

You said forty or fifty. That's not many, when they come four and
eight to the whack. Even 64 isn't that large. Synchronization is
*NOT* your problem. That's the easy part.

Digital audio consoles are off the shelf items these days, Harris
Broadcast, Wheatstone and others.

<http://harrisbroadcast.com/products/transmission/radio-transmitters-consoles>
<http://wheatstone-tv.com/>


--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.

 

[Joerg]

Alexander Y. Sure wrote:

On 26/02/14 06:01, Joerg wrote:
Folks,

The AC97 standard describes only up to four sound chips operated
simultaneously, on page 21:

ftp://download.intel.com/support/motherboards/desktop/sb/ac97_r23.pdf

What if one would like to connect, say, 20 of them and all are supposed
to run nicely synchronous? Like in a digital mixer board for music.


What you want to look into is not AC'97 but the more modern Intel High
Definition Audio (HDA)specification. It supports 500 bit slots for input
(~15 32 bit channels) multi codec streams and synchronization.

http://tinyurl.com/ln2oew8

Thanks, that looks very intersting. It is limited to 16 channels per
stream. However, per 4.5.7.2 in this document multiple streams can be
synchronized.

HDA codecs are very cheap. Realtek ALC889 go for ~0.6$ in single digit
quantities.

http://tinyurl.com/kcxzcs2

That one doesn't seem to have made in into the mainstream. Findchips
doesn't find a single distributor which is usually bad news. But it's
there, somewhere:

http://www.realtek.com.tw/products/productsView.aspx?Langid=1&PFid=28&Level=5&Conn=4&ProdID=173

The interface would be predominantly a FIFO with a few ornaments.

If this standard really establishes itself like AC97 did there should be
support chips coming out of the woodwork soon.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Joerg]

Jeorg's friend wrote:

Jeorg,

Wavefront Semiconductor makes the ADAT chips.

Look at AES3 / SPDIF

Interesting, AES was published in 1985 but somehow must have hissed out
in the consumer world. S/PDIF isn't even available on many computers
(like all of mine). The chips have it but the manufacturers decided not
to pipe it out. The only device I ever had with S/PDIF is the amplifier
box here at my office PC which I then had to rework so it would take
analog signals. AFAICT the optical TOSLINK connection method which was
propagated along with S/PDIF is completely fizzled in the marketplace.

I'll have to check this out. In the end the number and most of all the
availability of sound chips for the various standards will decide.

Don't ask me why I know, but your not the first to have this problem.

Yep, that's what I imagined

But it has to be financially sane. For example, I cannot use a standard
that requires super-expensive proprietary hardware.

--
Regards, Joerg

http://www.analogconsultants.com/

 

On Mon, 03 Mar 2014 04:10:34 -0500, "Michael A. Terrell"
<mike.terrell@earthlink.net> wrote:

krw@attt.bizz wrote:

You said forty or fifty. That's not many, when they come four and
eight to the whack. Even 64 isn't that large. Synchronization is
*NOT* your problem. That's the easy part.


Digital audio consoles are off the shelf items these days, Harris
Broadcast, Wheatstone and others.

http://harrisbroadcast.com/products/transmission/radio-transmitters-consoles
http://wheatstone-tv.com/

Yeah, those will be cost effective to build a product around.

 

[Jeorg's Friend.]

A couple of mainstream manufacturers (ie Crystal Semi) have SPDIF 7.1 Encoder/Decoders.

Steve

 

[josephkk]

On Sat, 1 Mar 2014 10:29:45 -0800 (PST), Lasse Langwadt Christensen
<langwadt@fonz.dk> wrote:

Den torsdag den 27. februar 2014 19.01.33 UTC+1 skrev Joerg:
Lasse Langwadt Christensen wrote:

Den torsdag den 27. februar 2014 02.38.03 UTC+1 skrev Joerg:

snip
Not really but close. If there is a delay of a few seconds that's ok but

there will be signals coming in all the time, continuously.


ok, so you'll be processing it in real time, I'd think that an fpga or MCU
with USB giving you a nice stream of all you channels would be less hassle than trying to get the whole windows/linux audio system to play nice with multiple channels

something like a small FPGA for sync and de-serializing and an FT2232H
for USB. One channel for configuring the FPGA, other as parallel FIFO

-Lasse

I don't think it will be that easy. This will be pushing something like
6MB/s (~60 Mb/s) through USB 2 or 3 continuously. Will the FT2232H handle
that?

?-)

 

[Michael A. Terrell]

krw@attt.bizz wrote:

On Mon, 03 Mar 2014 04:10:34 -0500, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:


krw@attt.bizz wrote:

You said forty or fifty. That's not many, when they come four and
eight to the whack. Even 64 isn't that large. Synchronization is
*NOT* your problem. That's the easy part.


Digital audio consoles are off the shelf items these days, Harris
Broadcast, Wheatstone and others.

http://harrisbroadcast.com/products/transmission/radio-transmitters-consoles
http://wheatstone-tv.com/

Yeah, those will be cost effective to build a product around.

Typical stupid reply. They are an example that it IS being done.


--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.

 

On Tue, 04 Mar 2014 05:21:21 -0500, "Michael A. Terrell"
<mike.terrell@earthlink.net> wrote:

krw@attt.bizz wrote:

On Mon, 03 Mar 2014 04:10:34 -0500, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:


krw@attt.bizz wrote:

You said forty or fifty. That's not many, when they come four and
eight to the whack. Even 64 isn't that large. Synchronization is
*NOT* your problem. That's the easy part.


Digital audio consoles are off the shelf items these days, Harris
Broadcast, Wheatstone and others.

http://harrisbroadcast.com/products/transmission/radio-transmitters-consoles
http://wheatstone-tv.com/

Yeah, those will be cost effective to build a product around.


Typical stupid reply.

No, you post made *no* sense.

>They are an example that it IS being done.

Of course there are digital mixing boards. Of *course* it can be
done. Good grief. If you need to state the obvious, tell us that the
sun rises in the East. It's not a solution for Joerg's problem, in
any way.

 

[Joerg]

Jeorg's Friend. wrote:

A couple of mainstream manufacturers (ie Crystal Semi) have SPDIF 7.1 Encoder/Decoders.

AFAIK S/PDIF is very limited in the number of channels but not sure, I
have to research that.

--
Regards, Joerg

http://www.analogconsultants.com/

 

On Tue, 04 Mar 2014 16:59:10 -0800, Joerg <invalid@invalid.invalid>
wrote:

Jeorg's Friend. wrote:
A couple of mainstream manufacturers (ie Crystal Semi) have SPDIF 7.1 Encoder/Decoders.


AFAIK S/PDIF is very limited in the number of channels but not sure, I
have to research that.

S/PDIF is quite limited. Unless you need to leave the box, it's far
more complicated than needed, too. There are better solutions, even
then.

 

[Joerg]

krw@attt.bizz wrote:

On Tue, 04 Mar 2014 16:59:10 -0800, Joerg <invalid@invalid.invalid
wrote:

Jeorg's Friend. wrote:
A couple of mainstream manufacturers (ie Crystal Semi) have SPDIF 7.1 Encoder/Decoders.

AFAIK S/PDIF is very limited in the number of channels but not sure, I
have to research that.

S/PDIF is quite limited. Unless you need to leave the box, it's far
more complicated than needed, too. There are better solutions, even
then.

It also has largely fizzled in the marketplace. You can't buy the
TOSLINK stuff as easily anymore as it used to be. My PC has a chip with
S/PDIF but it's not even piped out.

--
Regards, Joerg

http://www.analogconsultants.com/