I started using sound cards long after the CD-ROM connectors were moved away from the sound card to the motherboard directly. Thus, I don't have any knowledge in their difference. I am curious to know how they differ from one another in their behaviour in Windows/DOS, if there is advantage in using one over the another and if either of them fixed/caused new problems.
Thank you.
previously known as Discrete_BOB_058
If we're talking about CD audio cables, the main benefit of using a digital connection is that you get clean, noise-free sound. Analog connections are prone to interference (which adds noise) while digital ones are not (or rather not in the same way).
Note that there are two methods to get digital CD audio under Win9x. One is to use a SPDIF cable which connects the digital audio pins on the CD-ROM drive to the corresponding set of pins on the sound card. This works fine with either VxD or WDM drivers. However, some PCI sound cards don't have the pins for a digital CD audio connection. Also, these pins are very rarely present on ISA sound cards.
The other way is to use the internal data bus of the computer to transfer digital CD audio. This doesn't require any extra cables but (depending on the sound card) you often need to use WDM drivers, which are suboptimal under Win9x as they can reduce game compatibility. Lastly, you need to activate the "Enable Digital CD Audio" checkbox under the Device Manager entry for your CD-ROM drive in order for this to work.
Joseph_Joestar wrote on 2022-10-11, 06:51:If we're talking about CD audio cables, the main benefit of using a digital connection is that you get clean, noise-free sound. Analog connections are prone to interference (which adds noise) while digital ones are not (or rather not in the same way).
Note that there are two methods to get digital CD audio under Win9x. One is to use a SPDIF cable which connects the digital audio pins on the CD-ROM drive to the corresponding set of pins on the sound card. This works fine with either VxD or WDM drivers. However, some PCI sound cards don't have the pins for a digital CD audio connection. Also, these pins are very rarely present on ISA sound cards.
The other way is to use the internal data bus of the computer to transfer digital CD audio. This doesn't require any extra cables but (depending on the sound card) you often need to use WDM drivers, which are suboptimal under Win9x as they can reduce game compatibility. Lastly, you need to activate the "Enable Digital CD Audio" checkbox under the Device Manager entry for your CD-ROM drive in order for this to work.
Good explanation 😀
I have some question:
previously known as Discrete_BOB_058
BEEN_Nath_58 wrote on 2022-10-11, 13:31:Do CD-ROM drives containing analog audio pins exist?
Typically, IDE CD-ROM drives contain two sets of pins for CD audio: a 4 pin header (used for the analog CD audio cable) and a 2 pin header (used for the digital CD audio cable).
If they exist, can you do analog -> digital or vice versa?
No, you can't connect the digital pins of the CD-ROM drive to the analog input on the sound card, nor vice versa.
Why do VxD drivers don't work with digital connection?
They work fine if a digital CD audio cable is used. But you (usually) cannot tick the "Enable Digital CD Audio" checkbox to transfer CD audio over the internal bus when using VxD drivers. As I have already explained above, those are two separate and different methods for getting digital CD audio.
Hypothetically, what happens if you don't enable "Enable Digital CD Audio"?
If you have no cable going from the CD-ROM drive to the sound card, then you get no CD audio unless that setting is enabled.
Without an audio cable in 9x upward, it's just reading and decoding raw data through the IDE interface as if it was ripping the disk. This has a lot of CPU overhead. So even if you've got Win98 running and the digital decoding enabled, you will tend to have problems running games with high CPU demand and CD Audio, since it will put extra demands on CPU.
While it seems like you should have higher quality CD audio through the IDE audio decoding.... you probably don't. The drives with analog audio jack will have the CD quality 48khz DAC in there, which will pipe through direct to output on your soundcard with the audio cable, but if you play it through the IDE decoding, n ot only is there the 1.4Mbit/sec "tax" on the i/o, you'll only play it out as well as your soundcard can though it's DAC, so it might be limited to 44khz or 22 khz even. By the turn of milenium higher end soundcards might be better though.
Also an issue is older drive might not actually support DAE digital audio extraction... so you get a classic 8x and stick it in a newer machine with no CD audio input and you can't play audio CDs (unless you stick headphones in it's front jack if it's got one)
In general I'd recommend that on sub 1Ghz machines, you try to use drives with an analog audio hookup where possible.
Rare drives however also have an SPDIF digital, which requires a soundcard or onboard sound that can speak that, I think it's less CPU overhead, all being handled by custom hardware, but don't mess with it myself.
Unicorn herding operations are proceeding, but all the totes of hens teeth and barrels of rocking horse poop give them plenty of hiding spots.
BitWrangler wrote on 2022-10-11, 14:51:Rare drives however also have an SPDIF digital, which requires a soundcard or onboard sound that can speak that, I think it's less CPU overhead, all being handled by custom hardware, but don't mess with it myself.
I don't think the digital (SPDIF) header is rare. Pretty much all of my CD/DVD drives made between 1999 and 2005 have it.
In terms of sound cards which can accept that, most of Creative's products from the first SBLive onward have a CD_SPDIF header. I haven't noticed a performance penalty when using this connection, at least not on SBLive and Audigy cards. On the other hand, getting digital CD audio from the internal bus does indeed impact performance, regardless of which sound card is used.
BitWrangler wrote on 2022-10-11, 14:51:Without an audio cable in 9x upward, it's just reading and decoding raw data through the IDE interface as if it was ripping the disk. This has a lot of CPU overhead. So even if you've got Win98 running and the digital decoding enabled, you will tend to have problems running games with high CPU demand and CD Audio, since it will put extra demands on CPU.
So having no audio cable through to soundcard is equivalent to putting the CD-ROM connected directly to the motherboard and making the CPU do reading and decoding, just like most media players today?
BitWrangler wrote on 2022-10-11, 14:51:While it seems like you should have higher quality CD audio through the IDE audio decoding.... you probably don't. The drives with analog audio jack will have the CD quality 48khz DAC in there, which will pipe through direct to output on your soundcard with the audio cable, but if you play it through the IDE decoding, n ot only is there the 1.4Mbit/sec "tax" on the i/o, you'll only play it out as well as your soundcard can though it's DAC, so it might be limited to 44khz or 22 khz even. By the turn of milenium higher end soundcards might be better though.
I would love to understand this situation better:
1) What does the drive DAC do? shouldn't CPU be doing DAC functions, just like a soundcard would with it's DAC (considering you use the audio cable)?
2) why does "you'll play it out as well as your soundcard can through it's DAC" if I use IDE channel? Shouldn't the Taxed I/O introduce stutters instead of lowering the quality?
BitWrangler wrote on 2022-10-11, 14:51:Also an issue is older drive might not actually support DAE digital audio extraction... so you get a classic 8x and stick it in a newer machine with no CD audio input and you can't play audio CDs (unless you stick headphones in it's front jack if it's got one)
Since I heard DAE for first time, does it mean "sending analog audio data to a computer through a data bus"? Is there any general speed rating such as 16x, 24x, which makes sure DAE is supported?
BitWrangler wrote on 2022-10-11, 14:51:Rare drives however also have an SPDIF digital, which requires a soundcard or onboard sound that can speak that, I think it's less CPU overhead, all being handled by custom hardware, but don't mess with it myself.
Isn't this what Joseph explained earlier?
Joseph_Joestar wrote on 2022-10-11, 15:51:BitWrangler wrote on 2022-10-11, 14:51:Rare drives however also have an SPDIF digital, which requires a soundcard or onboard sound that can speak that, I think it's less CPU overhead, all being handled by custom hardware, but don't mess with it myself.
I don't think the digital (SPDIF) header is rare. Pretty much all of my CD/DVD drives made between 1999 and 2005 have it.
In terms of sound cards which can accept that, most of Creative's products from the first SBLive onward have a CD_SPDIF header. I haven't noticed a performance penalty when using this connection, at least not on SBLive and Audigy cards. On the other hand, getting digital CD audio from the internal bus does indeed impact performance, regardless of which sound card is used.
i do have a few more question:
1) There are CD drives with a volume button in front. Does that change only the CD music volume in application or the volume of entire computer?
2) WinMM emulators have an emulate cd Aux option. I assume Aux is some supplimentary hardware or button for the CD music. Can you tell what's an Aux device related to cd music?
previously known as Discrete_BOB_058
BEEN_Nath_58 wrote on 2022-10-13, 13:52:1) There are CD drives with a volume button in front. Does that change only the CD music volume in application or the volume of entire computer?
That's for the headphone jack on the front of the CD-ROM drive. If you plug your headphones directly into that jack, you get (only) CD audio and the wheel adjusts its volume. Some older CD-ROM drives also had play/stop controls on the front, so you could use them to play audio CDs without running a dedicated program on the computer.
2) WinMM emulators have an emulate cd Aux option. I assume Aux is some supplimentary hardware or button for the CD music. Can you tell what's an Aux device related to cd music?
I'm not familiar with WinMM emulators so I can't answer that. However, I can tell you that sound cards did have an analog AUX input back in DOS/Win9x days. IIRC, it was used for MPEG decoder cards, TV tuner cards and similar devices.
BEEN_Nath_58 wrote on 2022-10-13, 13:52:BitWrangler wrote on 2022-10-11, 14:51:Without an audio cable in 9x upward, it's just reading and decoding raw data through the IDE interface as if it was ripping the disk. This has a lot of CPU overhead. So even if you've got Win98 running and the digital decoding enabled, you will tend to have problems running games with high CPU demand and CD Audio, since it will put extra demands on CPU.
So having no audio cable through to soundcard is equivalent to putting the CD-ROM connected directly to the motherboard and making the CPU do reading and decoding, just like most media players today?
Yes, it's a very minor load for modern CPUs. Not so minor for pre year 2000.
BEEN_Nath_58 wrote on 2022-10-13, 13:52:I would love to understand this situation better: 1) What does the drive DAC do? shouldn't CPU be doing DAC functions, just like […]
BitWrangler wrote on 2022-10-11, 14:51:While it seems like you should have higher quality CD audio through the IDE audio decoding.... you probably don't. The drives with analog audio jack will have the CD quality 48khz DAC in there, which will pipe through direct to output on your soundcard with the audio cable, but if you play it through the IDE decoding, n ot only is there the 1.4Mbit/sec "tax" on the i/o, you'll only play it out as well as your soundcard can though it's DAC, so it might be limited to 44khz or 22 khz even. By the turn of milenium higher end soundcards might be better though.
I would love to understand this situation better:
1) What does the drive DAC do? shouldn't CPU be doing DAC functions, just like a soundcard would with it's DAC (considering you use the audio cable)?
2) why does "you'll play it out as well as your soundcard can through it's DAC" if I use IDE channel? Shouldn't the Taxed I/O introduce stutters instead of lowering the quality?
Something needs to make the digital data into analog audio at some point, the DAC in the CD drive makes it into analog that can be taken out of the rear header, or the front jack if equipped, it does this with a 16bit DAC capable of 48khz sample rate. If you connect the analog to the soundcard, it's connected more or less in parallel to other sounds the cards makes, but may go through a small amplifier with them, if it has one. If reading digital through the IDE cable, something has to turn it into analog audio at some point and that something is the soundcard or onboard audio, and it can't do a higher bitrate than it's designed for so there may also have to be downconversion performed by CPU before it can be played. This only applies to earlier soundcards, such as SBPro 2 class, SB16 class, later soundcards had faster DACs so could play the digital audio stream at the same rate it was stored at. So the quality lowers if a card with a slower DAC does the conversion and ALSO the demand on I/O and CPU may introduce stuttering in high load scenarios.
BEEN_Nath_58 wrote on 2022-10-13, 13:52:BitWrangler wrote on 2022-10-11, 14:51:Also an issue is older drive might not actually support DAE digital audio extraction... so you get a classic 8x and stick it in a newer machine with no CD audio input and you can't play audio CDs (unless you stick headphones in it's front jack if it's got one)
Since I heard DAE for first time, does it mean "sending analog audio data to a computer through a data bus"? Is there any general speed rating such as 16x, 24x, which makes sure DAE is supported?
It means the capability of the drive to read the digital audio tracks in data mode so it can pull the digital data through IDE... it's a fuzzy boundary where DAE Digital Audio Extraction worked and didn't, it was a high end feature very early on, some 1x 2x SCSI drives for professional market may do it, but it was less common in early IDE drives up to 8x, then more common thereafter, though there were still drives that didn't do it... mostly made by companies that had relationships with the music recording industry.
BEEN_Nath_58 wrote on 2022-10-13, 13:52:BitWrangler wrote on 2022-10-11, 14:51:Rare drives however also have an SPDIF digital, which requires a soundcard or onboard sound that can speak that, I think it's less CPU overhead, all being handled by custom hardware, but don't mess with it myself.
Isn't this what Joseph explained earlier?
Yuo, though I was referring to pre-2000ish classic era as it being a rarer feature then, it did become more common later.
BEEN_Nath_58 wrote on 2022-10-13, 13:52:1) There are CD drives with a volume button in front. Does that change only the CD music volume in application or the volume of entire computer?
2) WinMM emulators have an emulate cd Aux option. I assume Aux is some supplimentary hardware or button for the CD music. Can you tell what's an Aux device related to cd music?
That changes the analog volume at the drive, it may only affect the headphone jack or may affect the rear analog. If it's right next to jack, probably only that.
Aux usually means auxilliary input, the kind of thing you plug an analog CD audio cable into. So it would emulate it as an analog input.
Edit: as Joe says, the front panel controls are independant of software and drivers on the computer. One can use a CDROM with front panel controls as a standalone CD player, it only needs power and some connection to amp and speakers, whether you make a line in cord that fits the analog header at the back, or use a cassette adapter plugged into the headphone jack on front or something.
Unicorn herding operations are proceeding, but all the totes of hens teeth and barrels of rocking horse poop give them plenty of hiding spots.
I guess the important point to note is that in pure DOS only analog will come through. IDE digital mode might not work for DOS games in a windows DOS session, it might work for windows games with CD audio if they are for 98 up.
Unicorn herding operations are proceeding, but all the totes of hens teeth and barrels of rocking horse poop give them plenty of hiding spots.
BitWrangler wrote on 2022-10-13, 14:41:I guess the important point to note is that in pure DOS only analog will come through.
The SPDIF digital CD audio connection will work in pure DOS too, albeit with some caveats. In my experience, how well this functions depends on the sound card.
For example, I use an Audigy card in Win98 and have it connected to the CD-ROM drive using a SPDIF cable. In this situation, DOS games can play CD audio just fine while running from within Win9x. They will also play CD audio properly if I go to pure DOS using the "Restart in MS-DOS mode" option. However, if I boot straight to DOS (without loading Windows first) then digital CD audio will not play. I'm guessing Windows needs to initialize the Audigy card to make this work correctly. There may be some third-party tools which can also do this, but I haven't used them personally.
On the other hand, a different sound card based on the CMI8330 chip has proper DOS driver support for digital CD audio (using a SPDIF cable) and it works just fine in pure DOS, without the need to load Windows at all.
Yeah I suspected that, but wasn't gonna try to explain it, with the additional hurdle of most cards supporting it being PCI, and their issues being recognised by DOS games, and being late enough in the game that good DOS drivers were an afterthought etc etc.
Unicorn herding operations are proceeding, but all the totes of hens teeth and barrels of rocking horse poop give them plenty of hiding spots.
BitWrangler wrote on 2022-10-13, 14:33:Something needs to make the digital data into analog audio at some point, the DAC in the CD drive makes it into analog that can be taken out of the rear header, or the front jack if equipped, it does this with a 16bit DAC capable of 48khz sample rate. If you connect the analog to the soundcard, it's connected more or less in parallel to other sounds the cards makes, but may go through a small amplifier with them, if it has one. If reading digital through the IDE cable, something has to turn it into analog audio at some point and that something is the soundcard or onboard audio, and it can't do a higher bitrate than it's designed for so there may also have to be downconversion performed by CPU before it can be played. This only applies to earlier soundcards, such as SBPro 2 class, SB16 class, later soundcards had faster DACs so could play the digital audio stream at the same rate it was stored at. So the quality lowers if a card with a slower DAC does the conversion and ALSO the demand on I/O and CPU may introduce stuttering in high load scenarios.
Okay it is clearer now but I still have "basic" things to ask. I will take a game CD containing mixed-mode data, let's say Half-Life:
For the following, correct me wherever I am wrong
This questions may sound ridiculous, but computers here just wasn't a thing then.
Joseph_Joestar wrote on 2022-10-13, 14:20:I'm not familiar with WinMM emulators so I can't answer that. However, I can tell you that sound cards did have an analog AUX input back in DOS/Win9x days. IIRC, it was used for MPEG decoder cards, TV tuner cards and similar devices.
The emulator description said it: "pretends that there are aux ports dedicated to the sound mixer and the CD device. Some games control the volume level by changing the volume at the aux ports, so this may let the volume control of the emulated CD to work. It should be used when necessary." Do you have any ideas what it may mean?
previously known as Discrete_BOB_058
BEEN_Nath_58 wrote on 2022-10-13, 15:57:The emulator description said it: "pretends that there are aux ports dedicated to the sound mixer and the CD device. Some games control the volume level by changing the volume at the aux ports, so this may let the volume control of the emulated CD to work. It should be used when necessary." Do you have any ideas what it may mean?
Not sure. I don't use PC emulators so I can only speculate.
My guess is that they are emulating an analog CD audio connection, like BitWrangler suggested earlier.
Joseph_Joestar wrote on 2022-10-13, 16:08:BEEN_Nath_58 wrote on 2022-10-13, 15:57:The emulator description said it: "pretends that there are aux ports dedicated to the sound mixer and the CD device. Some games control the volume level by changing the volume at the aux ports, so this may let the volume control of the emulated CD to work. It should be used when necessary." Do you have any ideas what it may mean?
Not sure. I don't use PC emulators so I can only speculate.
My guess is that they are emulating an analog CD audio connection, like BitWrangler suggested earlier.
I read the MS docs and they define it as a way to emulate auxiliary device functions, such as auxSetVolume, auxGetDevCaps etc. But they didn't define what's an auxiliary device.
All I know is this option in the wrapper should fix CD audio of games: Sentinel Returns and Pandemonium! (Well that's out of topic)
previously known as Discrete_BOB_058
Joseph_Joestar wrote on 2022-10-13, 15:17:The SPDIF digital CD audio connection will work in pure DOS too, albeit with some caveats. In my experience, how well this functions depends on the sound card.
For example, I use an Audigy card in Win98 and have it connected to the CD-ROM drive using a SPDIF cable. In this situation, DOS games can play CD audio just fine while running from within Win9x. They will also play CD audio properly if I go to pure DOS using the "Restart in MS-DOS mode" option. However, if I boot straight to DOS (without loading Windows first) then digital CD audio will not play. I'm guessing Windows needs to initialize the Audigy card to make this work correctly. There may be some third-party tools which can also do this, but I haven't used them personally.
It's actually just a mixer problem. By default the digital CD mixer source is muted on SB Live/Audigy.
But you can enable it even without loading the DOS drivers e.g. by this utility:
Multichannel DOS mixer for DOS sound builds v0.49 for Live, v1.01 for Audigy
Falcosoft wrote on 2022-10-13, 20:04:It's actually just a mixer problem. By default the digital CD mixer source is muted on SB Live/Audigy.
But you can enable it even without loading the DOS drivers e.g. by this utility:
Multichannel DOS mixer for DOS sound builds v0.49 for Live, v1.01 for Audigy
Nice! I was aware of that utility but I haven't tried it so far, simply because I rarely use my Audigy in pure DOS (I have ISA sound cards for that).
Still, good to know that this can be addressed. The mixer which comes with the Audigy DOS drivers is very basic and could definitively use more options.
