Such software does exist and was often bundled with early CDROM drives. Usually it just needs the CDROM driver and MSCDEX to be loaded to work and is typically compatible with all drives .

You should be able to find some fancier ones on old shareware/freeware compilation CDs.

You will also need a drive with an S/PDIF output and a DAC that tolerates 5V S/PDIF ( or some kind of level shifter or converter or maybe).

EDIT: Some options listed here Music CD players for MS-DOS for software

Ah but I wasn't thinking about using S/PDIF - I am talking about transferring the digital data over the IDE cable.

Although finding a drive with digital-out is also an option, but won't work with sound cards missing an input.

ltning wrote on 2022-09-29, 16:08:

Ah but I wasn't thinking about using S/PDIF - I am talking about transferring the digital data over the IDE cable.

Although finding a drive with digital-out is also an option, but won't work with sound cards missing an input.

Doing this over IDE in DOS is certainly possible, but no idea if it's been done before as it would require special software that might not exist (or I don't know or remember any). You would need to "rip" the CD in real-time and feed it to a sound card without glitches under DOS. DOS CD rippers do exist, but I don't recall anything that rips and plays simultaneously.

You don't need a sound card to use a drive's S/PDIF output and the output is always active, i.e. same audio data that gets sent to the drive's internal DAC gets sent through S/PDIF (on all drives I've used) when an audio CD is played, so you could just hook that up to an external standalone DAC or AV receiver with proper digital input (if you can deal with the 5V S/PDIF)

Once upon a time, I did such a thing...
but it involved two programs: one to read the entire CD-DA track to a WAV file, and another to play the WAV.
It would be perfectly possible to combine them into one program, but I'm not sure if it would be possible to avoid buffering of the entire track...
reading CD-DA can be tricky, there's no guarantee the read occurs exactly where requested, some de-jittering may be necessary.

Grzyb wrote on 2022-09-29, 16:24:

Once upon a time, I did such a thing... but it involved two programs: one to read the entire CD-DA track to a WAV file, and anot […]
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Once upon a time, I did such a thing...
but it involved two programs: one to read the entire CD-DA track to a WAV file, and another to play the WAV.
It would be perfectly possible to combine them into one program, but I'm not sure if it would be possible to avoid buffering of the entire track...
reading CD-DA can be tricky, there's no guarantee the read occurs exactly where requested, some de-jittering may be necessary.

That's why I think using S/PDIF and an external DAC would be preferable in this case as it woukd let the drive do the heavy lifting. I haven't tried it, but I would not be surprised if cheap but relatively decent Fiio D3 could handle 5V S/PDIF without issue .

EDIT: There are motherboard slot brackets designed to convert 5V S/PDIF from a motherboard to Toslink optical. One could adapt one of those.

Mpxplay for DOS uses digital audio extraction exclusively for playing CD audio.
https://mpxplay.sourceforge.net/

Press Alt + F1 to select your CD drive. Then you can play the tracks as 'cdw' files:

Falcosoft wrote on 2022-09-29, 17:07:

Mpxplay for DOS uses digital audio extraction exclusively for playing CD audio.
https://mpxplay.sourceforge.net/

Press Alt + F1 to select your CD drive. Then you can play the tracks as 'cdw' files:

Nice! TY, I did not know of that feature .

Falcosoft wrote on 2022-09-29, 17:07:

Mpxplay for DOS uses digital audio extraction exclusively for playing CD audio.
https://mpxplay.sourceforge.net/

Press Alt + F1 to select your CD drive. Then you can play the tracks as 'cdw' files:

I've never been able to make mpxplay work - maybe it's my hardware. Should I expect it to run on, say, a 386DX40? Or do I need to break out a DLC or SXL-CPU for that machine?

ltning wrote on 2022-09-29, 17:54:

Falcosoft wrote on 2022-09-29, 17:07:

Mpxplay for DOS uses digital audio extraction exclusively for playing CD audio.
https://mpxplay.sourceforge.net/

Press Alt + F1 to select your CD drive. Then you can play the tracks as 'cdw' files:

I've never been able to make mpxplay work - maybe it's my hardware. Should I expect it to run on, say, a 386DX40? Or do I need to break out a DLC or SXL-CPU for that machine?

I'm not sure but for real-time extraction + playback I would suggest a 486DX2-66 with 8MB RAM as a minimum.
BTW the readme has recommendations for different compressed formats but not for real-time CD audio:

Mpxplay system requirements (mainly for DOS): […]
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Mpxplay system requirements (mainly for DOS):

- Minimum CPU for playing 44.1khz, stereo, (128kbit/s) files (with '-f0 -sl 0 -bl -bn8' options):

AAC : Intel Pentium 66 (LC object type)
AC3 : Intel 80486 DX4-120 (48khz,2.0ch,192kbit)
APE : Intel Pentium 166 MMX (fast-mode encoded files work without MMX too)
DTS : Intel PII-300 (48kHz,5.1ch,768kbit)
FLAC: Intel Pentium 66 (depending on the compression ratio too)
MP2 : Intel 80486 DX2-66
MP3 : Intel 80486 DX4-100
MPC : Intel 80486 DX4-100
OGG : Intel 80486 DX4-133
WMA : Intel Pentium 90
WV : Intel Pentium 166

Also CD digital audio extraction was not a thing in the 386/486 era so using contemporary hardware is not the best choice. DAE at least requires a more 'modern' CD/DVD drive.

Realtime audio streaming from a CD over IDE (including all the buffering and overlapping read logic and sync logic), presumably using CPU intensive PIO on a 386DX40 seems like a tall order.

First, try the attached programs and see if your CD-ROM drive can properly read CDDA sectors.
Second, try to play the WAV file and see if your machine is fast enough for CD-quality playback.
If both succeed, you can modify the source code to send the data to the sound card, instead of writing it to the file...

Whoa, that's cool stuff.
So I was able to read (at 3-4x speed, average) the CD audio from my drive, and subsequently play it back with the GUS Extreme-suppled 'playfile' tool.
Sounds great - basically no noise compared to running via CD-audio input.
This on a 386 DX-40.

Now I'm not a C coder, but at least this shows it is theoretically possible. I have no idea how much CPU and bus bandwidth reading into memory and pumping back out on the BUS to the sound card is going to require; at 16 bits 44.1KHz stereo that's a theoretical 176400B/s, twice over is about 350KB/s. Even with overhead it should not tax the bus with more than 400KB/s total. CPU time spent should not be terrible as long as unnecessary wrapping/unwrapping/recoding of data isn't happening - but I suppose the data from the drive isn't immediately ready for dumping onto the sound card. For the same reason, and the need for a de-jitter buffer, I presume DMA can't be used (straight from IDE controller to sound card).