If I connect to a CD SPDIF header on a soundcard, will that signal be converted to analog audio by the soundcard's DAC, or would I be able to get digital cd audio out through the soundcard's optical/coax port?
And more importantly, is digital audio out even possible in a pure DOS environment anyway?
Depends on what you mean by "digital audio". Digital read-out? No, that requires Windows 98 or later and compatible drivers/hardware.
But if you have a CD-ROM drive with both analog and digital out, both will work when a DOS game plays CDDA. Whether you get that on the soundcard's digital out depends on the soundcard.
Thanks! Do you happen to know if digital out would work with a SB Live?
derSammler wrote on 2020-03-05, 17:48:Depends on what you mean by "digital audio". Digital read-out? No, that requires Windows 98 or later and compatible drivers/hardware.
If you're talking about reading digital audio from the disc via the IDE interface (aka, ripping) then no, it doesn't require 98. There are DOS ripping tools. However, at least all those I have used are meant for extracting audio tracks to WAV files, not real-time playback, and obviously don't have anything to do with the way other applications (like games) play CD audio tracks.
The digital audio port on the back of the CD-ROM is active in parallel to the analog port any time the drive is playing audio. Use whichever you'd like. In most cases, your sound card -- if it has a digital input -- will sample-rate convert that 16/44.1 stream to whatever its internal DSP sample rate is, process it through the mixer and, if applicable, effects. The output will appear on whatever analog and digital outputs the card has, but it won't be a pure 1:1 copy of the input stream anymore.
IIRC, the digital port on a CD-ROM is just SPDIF, but you might need an appropriate driver to expose that as coaxial or optical SPDIF. (Driver in this case being of the electronics type -- a buffer amp and transmitter IC, typically. Not a piece of software.)
don't quote me on it but I think it's TTL SPDIF on the 2 pin connector
SirNickity wrote on 2020-03-05, 23:56:If you're talking about reading digital audio from the disc via the IDE interface (aka, ripping) then no, it doesn't require 98. There are DOS ripping tools. However, at least all those I have used are meant for extracting audio tracks to WAV files, not real-time playback, and obviously don't have anything to do with the way other applications (like games) play CD audio tracks.
Since he talked about getting "digital cd audio out", I didn't even spend a minute thinking about tools for ripping. I don't think that is what he's after at all.
derSammler wrote on 2020-03-05, 17:48:The digital audio port on the back of the CD-ROM is active in parallel to the analog port any time the drive is playing audio. Use whichever you'd like.
This is the important bit of info I was looking for. I also suggest checking mixer settings for the card if you have them - this is what I forgot to check when I was wondering why things seemed to work but there was no sound. You may need to enable the routing from CD (or SPDIF) to Line Out.
Of course that's if you just wanna mix it in. If all you want to do is capture the digital output and route it externally, you will need to find a SPDIF module that has a header you can connect it to and appropriate port on the rear.
Sound device guides:
Sound Blaster
Aztech
OPL3-SA
SirNickity wrote on 2020-03-05, 23:56:In most cases, your sound card -- if it has a digital input -- will sample-rate convert that 16/44.1 stream to whatever its internal DSP sample rate is, process it through the mixer and, if applicable, effects. The output will appear on whatever analog and digital outputs the card has, but it won't be a pure 1:1 copy of the input stream anymore.
Ok, that's the information I've been looking for, many thanks!
derSammler wrote on 2020-03-06, 12:40:SirNickity wrote on 2020-03-05, 23:56:If you're talking about reading digital audio from the disc via the IDE interface (aka, ripping) then no, it doesn't require 98. There are DOS ripping tools. However, at least all those I have used are meant for extracting audio tracks to WAV files, not real-time playback, and obviously don't have anything to do with the way other applications (like games) play CD audio tracks.
Since he talked about getting "digital cd audio out", I didn't even spend a minute thinking about tools for ripping. I don't think that is what he's after at all.
I wasn't quite sure what you were referring to with "digital read-out". The digital audio output on a sound card doesn't have much to do with drivers or OS. If the card can be activated at all in DOS, CD audio pass-through generally works through any of the outputs the card physically has. So that didn't make sense. The only thing I could think of was how audio CD playback shifted from MCI commands to streaming PCM data around the time of Win98, so that's what I assumed you meant. The process itself doesn't require Win98, obviously, but it does require the playback software to use that method -- which won't be the case in DOS except for ripping tools.
Anyway, that was my thought process.
