If it's Red Book audio, most DOS titles trigger an MMC command to play the track. The audio is then output in both analog and TTL spdif format via the header on the back of the optical drive. Some DOS programs, such as MPXPlay, can perform DAE and render the audio via a sound card thus bypassing the decoder logic on the optical drive.

Try playing audio using any number of DOS cd players (you should have one included with your sound card drivers) and see if normal playback is triggered. Some CD drivers/extenders have trouble with the commands in question.

The easiest way to check, if the CD-ROM drive is old enough, is to stick some headphones into the jack on the front of the drive when the game is supposed to be playing the music (with Quake of course it's obvious - as the drive will be lit constantly during a level).

Check that is working first, then troubleshoot the audio out path from the rear of the CD-ROM drive to the CD-IN/LINE-IN of your soundcard.

Oh, and as far as I am aware, all DOS games use regular old play/next/stop drive commands to get the drive to play tracks, just like a regular old consumer CD player. What game is it, and are you sure it is using CD audio tracks? It's possible it's streamed audio (like Command and Conquer) where it is actually data read from the CD.

DustyShinigami wrote on 2024-12-08, 02:33:

Hi […]
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Hi

I'm currently looking into and trying to understand how to get CD audio to play in DOS, specifically for a game, and whether it needs to be analog or digital. There's an issue I'm trying to investigate where audio tracks are not playing during gameplay. A couple of other games haven't been an issue, such as Quake and Blood. They just work. But I'm wondering if some may require a different approach to get working. I've tried connecting a cable from the CD-ROM's Audio Output to the sound card, which was the old way of getting the audio to work, but it doesn't appear to be helping at all. And I'm not sure if there's something I can do in DOS to find out if the volume needs adjusting? Not a problem in Windows of course. I'm also not sure if digital audio is enabled in Windows. I need to check, but I'm sure it is. I just don't know if this is something I need to enable/configure in DOS? I don't think I have separate ports on the CD-ROM or sound card - one for Analog and one for Digital. There appears to be just one on each. I'd need to check again.

I believe the cable was originally connected from the CD-ROM to the motherboard. I'm guessing this would have been to get CD audio to work via onboard audio? I'm not even sure if the cable is working or not; I've not been able to check. Is it just a case of putting an audio CD in and loading/playing it via an audio mixer/control panel? Again, that would most likely work fine under Windows, but it's getting it working under DOS that's the issue. I need some way to test if it's working correctly as it should whilst under DOS. The CD-ROM driver is all set up and working under DOS. As I said, audio has worked for Quake and Blood, so I'm just totally at a loss as to why this one particular game isn't working.

Thanks

theres usually 2 connectors on some sound cards, one for sony drives and one for panasonic, each have a different pinout thats something to look out for, also check the connector on the back of your IDE drive, i was looking at one of mine yesterday, it has a connector but theres no pins in it 🤣. absolutely useless.
if its neither of those it could be that it may just be muted, so you'll need to load up the mixer in dos.

DustyShinigami wrote on 2024-12-08, 02:33:

Hi

I'm currently looking into and trying to understand how to get CD audio to play in DOS, specifically for a game, and whether it needs to be analog or digital.

Getting analog CD audio to work is relatively easy. You hook up one end of the 4 pin connector to the CD-ROM drive, and the other end to the relevant header on your sound card. Double check that the pins are oriented correctly (e.g. RGGL to RGGL) and make sure that the sound card mixer has the CD audio volume slider unmuted. That's all there is to it. Analog CD audio generally "just works" once initially set up, though it might be a bit noisy, depending on your setup.

Digital CD audio is a very different beast. Being digital, it's entirely noise free, and you can get it in two ways. The first one is over the IDE bus. For this, you need to use WDM drivers for the sound card under Win98, and then tick the "Enable Digital CD Audio" checkbox for your CD-ROM drive under Control Panel. I don't like this method because WDM sound card drivers slow down system performance, and aren't as compatible with EAX in older games.

The other way is to use a two pin SPDIF cable, which both your sound card and your CD-ROM drive need to support. This can be problematic, because some CD-ROM drives don't have the necessary pins installed, or even worse, have the pins present but they aren't actually connected and do nothing. Anyway, if you manage to get a sound card which supports this (e.g. Sound Blaster Live! with a working CD_SPDIF header) and a compatible CD/DVD drive (those manufactured between 2000-2004 usually work) then you need to hook them up using the two pin SPDIF cable and unmute the "CD Digital" volume slider under Win98. This method (usually) doesn't require WDM drivers and therefore doesn't slow down system performance. On the flip side, digital CD audio sometimes doesn't work in pure DOS, so there's a trade off.

gdjacobs wrote on 2024-12-08, 02:54:

If it's Red Book audio, most DOS titles trigger an MMC command to play the track. The audio is then output in both analog and TTL spdif format via the header on the back of the optical drive. Some DOS programs, such as MPXPlay, can perform DAE and render the audio via a sound card thus bypassing the decoder logic on the optical drive.

Try playing audio using any number of DOS cd players (you should have one included with your sound card drivers) and see if normal playback is triggered. Some CD drivers/extenders have trouble with the commands in question.

I'm not quite sure if my drivers did. I'll need to look into this further.

Joseph_Joestar wrote on 2024-12-08, 12:38:

Getting analog CD audio to work is relatively easy. You hook up one end of the 4 pin connector to the CD-ROM drive, and the othe […]
Show full quote

DustyShinigami wrote on 2024-12-08, 02:33:

Hi

I'm currently looking into and trying to understand how to get CD audio to play in DOS, specifically for a game, and whether it needs to be analog or digital.

Getting analog CD audio to work is relatively easy. You hook up one end of the 4 pin connector to the CD-ROM drive, and the other end to the relevant header on your sound card. Double check that the pins are oriented correctly (e.g. RGGL to RGGL) and make sure that the sound card mixer has the CD audio volume slider unmuted. That's all there is to it. Analog CD audio generally "just works" once initially set up, though it might be a bit noisy, depending on your setup.

Digital CD audio is a very different beast. Being digital, it's entirely noise free, and you can get it in two ways. The first one is over the IDE bus. For this, you need to use WDM drivers for the sound card under Win98, and then tick the "Enable Digital CD Audio" checkbox for your CD-ROM drive under Control Panel. I don't like this method because WDM sound card drivers slow down system performance, and aren't as compatible with EAX in older games.

The other way is to use a two pin SPDIF cable, which both your sound card and your CD-ROM drive need to support. This can be problematic, because some CD-ROM drives don't have the necessary pins installed, or even worse, have the pins present but they aren't actually connected and do nothing. Anyway, if you manage to get a sound card which supports this (e.g. Sound Blaster Live! with a working CD_SPDIF header) and a compatible CD/DVD drive (those manufactured between 2000-2004 usually work) then you need to hook them up using the two pin SPDIF cable and unmute the "CD Digital" volume slider under Win98. This method (usually) doesn't require WDM drivers and therefore doesn't slow down system performance. On the flip side, digital CD audio sometimes doesn't work in pure DOS, so there's a trade off.

Thank you for the easy to understand and thorough explanation. ^^ I'm not sure if my CD-ROM or sound card support a 2-pin SPDIF. I don't think they do, but I'll need to check. The basic volume mixer in Windows has the CD drive unmuted, so I'm guessing this will work fine. Just need to test a CD. And I need to find out if it's unmuted in DOS. I'll also have to see if there's an Enable Digital CD Audio checkbox. I don't know if I have, or can get, WDM drivers though. But if digital audio doesn't work in DOS anyway, then it's not something I'll need to worry about.

megatron-uk wrote on 2024-12-08, 09:57:

The easiest way to check, if the CD-ROM drive is old enough, is to stick some headphones into the jack on the front of the drive when the game is supposed to be playing the music (with Quake of course it's obvious - as the drive will be lit constantly during a level).

Check that is working first, then troubleshoot the audio out path from the rear of the CD-ROM drive to the CD-IN/LINE-IN of your soundcard.

Oh, and as far as I am aware, all DOS games use regular old play/next/stop drive commands to get the drive to play tracks, just like a regular old consumer CD player. What game is it, and are you sure it is using CD audio tracks? It's possible it's streamed audio (like Command and Conquer) where it is actually data read from the CD.

It's pretty old, but not old enough to have Play, Stop, Forward buttons on the front. I think I remember owning one once that did... At any rate, it has no jacks at the front at all. So I'll most likely have to test out headphones from the back.

And the game is the original DOS version of Tomb Raider. It has the audio/ambient tracks present. I tested it out on my main PC. VLC Player recognised the tracks. The CD player I did try on 98 didn't detect any CD though. I know the Sold-Out Software version has the tracks missing, but this is the OG version. 😀

DudeFace wrote on 2024-12-08, 11:22:

DustyShinigami wrote on 2024-12-08, 02:33:

Hi […]
Show full quote

Hi

I'm currently looking into and trying to understand how to get CD audio to play in DOS, specifically for a game, and whether it needs to be analog or digital. There's an issue I'm trying to investigate where audio tracks are not playing during gameplay. A couple of other games haven't been an issue, such as Quake and Blood. They just work. But I'm wondering if some may require a different approach to get working. I've tried connecting a cable from the CD-ROM's Audio Output to the sound card, which was the old way of getting the audio to work, but it doesn't appear to be helping at all. And I'm not sure if there's something I can do in DOS to find out if the volume needs adjusting? Not a problem in Windows of course. I'm also not sure if digital audio is enabled in Windows. I need to check, but I'm sure it is. I just don't know if this is something I need to enable/configure in DOS? I don't think I have separate ports on the CD-ROM or sound card - one for Analog and one for Digital. There appears to be just one on each. I'd need to check again.

I believe the cable was originally connected from the CD-ROM to the motherboard. I'm guessing this would have been to get CD audio to work via onboard audio? I'm not even sure if the cable is working or not; I've not been able to check. Is it just a case of putting an audio CD in and loading/playing it via an audio mixer/control panel? Again, that would most likely work fine under Windows, but it's getting it working under DOS that's the issue. I need some way to test if it's working correctly as it should whilst under DOS. The CD-ROM driver is all set up and working under DOS. As I said, audio has worked for Quake and Blood, so I'm just totally at a loss as to why this one particular game isn't working.

Thanks

theres usually 2 connectors on some sound cards, one for sony drives and one for panasonic, each have a different pinout thats something to look out for, also check the connector on the back of your IDE drive, i was looking at one of mine yesterday, it has a connector but theres no pins in it 🤣. absolutely useless.
if its neither of those it could be that it may just be muted, so you'll need to load up the mixer in dos.

I did see 2 connectors on the sound card. One is black and the other is white. I'll need to check the names on them. I believe the black one says Sony next to it. But yeah, my connector won't fit into the white one. I'm guessing I do just need to find and test out a volume mixer under DOS. 😀

DustyShinigami wrote on 2024-12-08, 15:21:

Thank you for the easy to understand and thorough explanation. ^^ I'm not sure if my CD-ROM or sound card support a 2-pin SPDIF. I don't think they do, but I'll need to check.

This two pin SPDIF header is very rare on ISA sound cards, but slightly more common on PCI sound cards.

Creative's SBLive and Audigy cards usually have it, except for the cheaper "value" models and some OEM versions. For other manufacturers, it varies.

Joseph_Joestar wrote on 2024-12-08, 15:41:

Creative's SBLive and Audigy cards usually have it, except for the cheaper "value" models and some OEM versions.

I had a SBLive! Value, and I did solder the header (just random arduino-like 2.54mm pins) to use SPDIF with CD-ROMs 😀

Okay, I took another lookie at the setup for the CD-ROM and sound card. There's no SPDIF port on either, I'm afraid. I re-arranged the cables so they were both RGGL, with right being the red cable, I believe? I did test the game after but there was no change. I tried an audio CD, which played, but there was no way of plugging in headphones into the drive from the front or the back. Only from the right speaker. And checked if digital audio was enabled and sadly it's completely greyed out. So no digital audio. Not unless there are some WDM drivers for my particularly sound card...? Can't say I've come across any. And considering the year it was made, I doubt it's an option.

However, the problem I was having with Tomb Raider seems to have been resolved. In DOS anyway. And I think it was due to using the SETYMF utility and then saving the settings to the autoexec.bat and msdos.sys files. 😁

I just need to find some utility that lets me adjust the volume in DOS. The drivers I've installed didn't look to include anything from what I could see.

Tried out SETUPSA for adjusting the volume controls. I think, in the end, it's best to leave them at default. Audio seems to be louder in DOS over Windows anyway, so increasing things like the Master Volume only adds crackling and distortion from the speakers.

DustyShinigami wrote on 2024-12-08, 20:36:

Okay, I took another lookie at the setup for the CD-ROM and sound card. There's no SPDIF port on either, I'm afraid. I re-arranged the cables so they were both RGGL, with right being the red cable, I believe? I did test the game after but there was no change. I tried an audio CD, which played, but there was no way of plugging in headphones into the drive from the front or the back. Only from the right speaker. And checked if digital audio was enabled and sadly it's completely greyed out. So no digital audio. Not unless there are some WDM drivers for my particularly sound card...? Can't say I've come across any. And considering the year it was made, I doubt it's an option.

However, the problem I was having with Tomb Raider seems to have been resolved. In DOS anyway. And I think it was due to using the SETYMF utility and then saving the settings to the autoexec.bat and msdos.sys files. 😁

I just need to find some utility that lets me adjust the volume in DOS. The drivers I've installed didn't look to include anything from what I could see.

Yeah, sounds like Tomb Raider was down to mixer settings.