Somehow, my trusty Chaintech av710 died and these cards don't seem to be available anymore. Now I'm on the hunt for a (cheap) sound card that does bit perfect audio, ideally up to 24bit/96khz.

This one seems to have a CMI 8768+, but I don't want to order unless I know for sure that it works: http://www.ncix.com/products/index.php?sku=23460

Bestbuy's "Dynex" house brand makes a Via Envy based card that might do it also, but it's only good up to 48khz.

US:
http://www.bestbuy.com/site/olspage.jsp?skuId=7180739&st=dynex+sound&lp=1&type=product&cp=1&id=1110267355627

Canada (price seems whacked compared to US):
http://www.bestbuy.ca/catalog/proddetail.asp?logon=&langid=EN&sku_id=0926INGFS10061572&catid=20400

Any one else know of any other readily available cards?

AFAIK, the root cause of non-bit-perfect audio in Windows was the low level OS audio architecture, which used a software component called "Kmixer" in the audio bit chain, which resamples audio in most cases, unless you did things like kernal streaming by exception to avoid the munging of audio due to Kmixer.

Also, some hardware cards like most of the SOund Blaster Live series did hardware resampling regardless of OS or Kmixer.

Bottom line- assuming you get a card that does not hardware-enforce resampling, you should get bit-perfect audio easily in Linux, since Linux doesn't have a Kmixer-like component in the audio processing chain (unless you want to).

My assumption is that most motherboard's with SPDIF out, and most non-Creative Labs PCI sound cards with SPDIF out *should* produce bit perfect audio, depending on Mixer and sound server settings in most Linuxes.

I bought this a few months ago, though I haven't tested it for bit perfect yet-
http://www.newegg.com/Product/Product.aspx?Item=N82E16829111001

Staples, Office MAx and other B&M's carry this, in case you want to test it and return it if it doesn't work for you.

Bit perfect audio is no big deal with a real operating system. I use the motherboard audio on my HTPC and get tested bitperfect digital output, with no extra work or special cards.

Daravon, could you share what soundcard and setup you have?

I'm trying to use an AD1986A (Nvidia HDA) and I can't get anything to play via spdif unless I force the audio through dmix which then resamples to 16bit/48KHz.



$ file 24bit-96hz.wav
24bit-96hz.wav: RIFF (little-endian) data, WAVE audio, Microsoft PCM, 24 bit, stereo 96000 Hz

$ aplay -D iec958 24bit-96hz.wav
Playing WAVE '24bit-96hz.wav' : Signed 24 bit Little Endian in 3bytes, Rate 96000 Hz, Stereo
aplay: set_params:901: Sample format non available

$ aplay -D hw:0,0 24bit-96hz.wav
Playing WAVE '24bit-96hz.wav' : Signed 24 bit Little Endian in 3bytes, Rate 96000 Hz, Stereo
aplay: set_params:901: Sample format non available

$ mplayer -ao alsa,hw:0,0 24bit-96hz.wav
[...]
Playing 24bit-96hz.wav.
Audio file file format detected.
============================================================ ==============
Forced audio codec: mad
Opening audio decoder: [pcm] Uncompressed PCM audio decoder
AUDIO: 96000 Hz, 2 ch, s24le, 4608.0 kbit/100.00% (ratio: 576000->576000)
Selected audio codec: [pcm] afm: pcm (Uncompressed PCM)
============================================================ ==============
[AO_ALSA] Format s24le is not supported by hardware, trying default.
AO: [alsa] 48000Hz 2ch s16le (2 bytes per sample)
[...]


The card documentation clearly states that it does 24bit @ 96khz but it appears as though the driver doesn't. This is a bog-standard out of the box Ubuntu 8.04 on an older Asus Nvidia 6150 board.


s$ lsmod | grep snd
snd_hda_intel 344728 7
snd_pcm_oss 42144 0
snd_mixer_oss 17920 1 snd_pcm_oss
snd_pcm 78596 2 snd_hda_intel,snd_pcm_oss
snd_page_alloc 11400 2 snd_hda_intel,snd_pcm
snd_hwdep 10500 1 snd_hda_intel
snd_seq_dummy 4868 0
snd_seq_oss 35584 0
snd_seq_midi 9376 0
snd_rawmidi 25760 1 snd_seq_midi
snd_seq_midi_event 8320 2 snd_seq_oss,snd_seq_midi
snd_seq 54224 6 snd_seq_dummy,snd_seq_oss,snd_seq_midi,snd_seq_midi_event
snd_timer 24836 2 snd_pcm,snd_seq
snd_seq_device 9612 5 snd_seq_dummy,snd_seq_oss,snd_seq_midi,snd_rawmidi,snd_seq
snd 56996 25 snd_hda_intel,snd_pcm_oss,snd_mixer_oss,snd_pcm,snd_hwdep,sn d_seq_dummy,snd_seq_oss,snd_rawmidi,snd_seq,snd_timer,snd_se q_device
soundcore 8800 1 snd

I just have a Biostar 7050PV motherboard and use the spdif out. I don't to anything in particular. All audio seems to play out the SPDIF; in case it isn't I just tell the application to use spdif and then it works. I send it to my surround receiver and it plays stereo pcm, 24 bit flac, Dolby, and DTS just fine.

I don't think my receiver is capable of sampling frequencies over 48kHz though since it's a home theatre device; I don't see the point of higher bitrates for end use anyway.

Somehow, my trusty Chaintech av710 died and these cards don't seem to be available anymore.

They are great cards don't know why Chaintech stopped making them. In any case if you are familiar with the card and how it works it might be best to just find another one to replace it, you can probably pick one up on ebay for not too much.

http://code.google.com/p/cmediadrivers/wiki/SupportedDevices

An enterprising individual built a windows driver for the C-Media 8738 and 8768 chips which are known to do bit-perfect out in linux also. The list above has lots of inexpensive options.