Apple IIGS wrote on 2021-08-19, 19:46:

Hello all - So, I have a NEC Versa VX (PIII laptop, circa 1999) with Yamaha YMF-752-S sound chip built-in and want to use it for […]
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Hello all - So, I have a NEC Versa VX (PIII laptop, circa 1999) with Yamaha YMF-752-S sound chip built-in and want to use it for playing old 90's era DOS games.

I've got its audio/MIDI-playback working under Windows 98, but for years have been trying, without success, to get sound to work under pure DOS! (whether choosing "Restart in MS-DOS mode" or booting directly into MS-DOS 6.22). I'd normally assume it has no native DOS support. What's interesting however, looking up the 752 spec sheet, I found this interesting tidbit of information!

The following functions are supported by using the software driver from YAMAHA.
• XG Wave Table Synthesizer
• Downloadable Sound (DLS)
• Legacy Audio (Sound Blaster Pro compatibility and FM Synthesizer) on Pure DOS

http://pdf.eepw.com.cn/120090707/1876a218d8f7 … 2_IG_zqHur0N5jw

From what I understand, as an AC-XG it offers XG wavetable synthesis (not sure if the patches are ROM embedded or software loaded) but unlike the DS-XG, no hardware based OLP3/FM? I think It does emulate FM synth and SB16 compatibility with drivers, and according to the above, they DO exist. The question is where? I've searched high and low and not found these pure DOS drivers anywhere. Someone out there must have them! Or at least someone here other than me has experience with the YMF-752 chipset and DOS.

ps - I'm a huge sound enthusiast! I have an SC-55mkII, SC-50, E-MU SoundEngine, Yamaha FB-01, Yamaha MU5, several PC synth sound cards (ISA SCC1's, Yamaha XG, AdLib), and keyboards (Ensoniq ESQ-1. SK-1's, Roland) and my IIGS's with Ensoniq DOC's built-in! Just to say, getting music synth to work in these old games is the main experience I want to relive. 😀

I think it is quite likely that the YMF-752 does not actually have any pure DOS compatibility. My guess is that info is actually an error (leftover from previous model or before design change) in the datasheet (the datasheet is labeled preliminary) . Contrary to datasheets for all known DOS supporting Yamaha controllers, this one does not have any mention of a legacy audio block in its diagram .

I think it is quite likely that the YMF-752 does not actually have any pure DOS compatibility. My guess is that info is actually an error (leftover from previous model or before design change) in the datasheet (the datasheet is labeled preliminary) . Contrary to datasheets for all known DOS supporting Yamaha controllers, this one does not have any mention of a legacy audio block in its diagram .

That's a possibility, and would explain why Yahama's driver support page only has Windows driver for it.

Though just to add uncertainty, here's an EE Times article from 1999 that ALSO specifically states the YMF-752 offers pure DOS support! They even mention FM support is emulated by the software: https://www.eetimes.com/ac97-codec-retains-le … K1OKiuy9Q7dxPXU

I'm less excited about its potential DOS support if the chipset has no hardware OPL3, but then again, it is capable of XG wavetable support too. I've had some limited success with the latter, running certain games from a Windows DOS prompt (e.g. DOOM II).

At any rate, I'd really like to get to the bottom of this once and for all. Could it be the DOS software driver is just vaporware....cancelled after the YMF-752 was released? Or is it out there to download?

The block diagram doesn't show OPL or a legacy block so I am pretty sure it doesn't actually support OPL or real mode DOS.

It also doesn't show a Wavetable block either.

Is it using the software XG synth in Windows?

cyclone3d wrote on 2021-08-20, 04:10:

The block diagram doesn't show OPL or a legacy block so I am pretty sure it doesn't actually support OPL or real mode DOS.

Glancing over tech specs, I noticed that too.

As far as OPL, I recently discovered this particular French driver provides emulated FM under a Windows DOS prompt, but it locks the computer up after a couple of seconds of playback (and far from being accurate, almost reminds me of SBOS for the GUS card). https://fr.driverscollection.com/?file_id=278 … rYa7BTXbbmjJM_w

It also doesn't show a Wavetable block either.

Is it using the software XG synth in Windows?

I was fairly sure it's a hardware XG synth (other than perhaps the patches/wavetable instruments, those are likely loaded from software and not ROM based. I don't see anything chip embedded in the diagram, and doubt there's any external masked ROMs accompanying such a budget chipset). Hmm, now I'm kinda curious if the AC-XG and DS-XGS are the real thing/hardware synth, or just software emulated (like the "Microsoft GS Wavetable SW synth" option that's based on the SC-55).

Yamaha doesn't have a DOS driver download for that particular chip, though they provide one for some others, which might work, though I have no evidence that it will.

I found an old, no longer in use download page that has a list of drivers for that era of soundcard, which Yamaha no longer supports.

The DS-XG is a hardware assisted synth.

The samples are loaded into the computer's RAM, bit the synth part is integrated.

Pretty sure this is the main reason why the synth is not available in real DOS.

Not sure about the AC-XG chips as I don't have cards with them.

cyclone3d wrote on 2021-08-20, 16:28:

The DS-XG is a hardware assisted synth.

The samples are loaded into the computer's RAM, bit the synth part is integrated.

Pretty sure this is the main reason why the synth is not available in real DOS.

The reason I asked about DS-XG, I also have a Sony VAIO PCG-N505VX (PII, 1999 era mini laptop) which reports "Yamaha DS-XG PCI Audio CODEC (WDMI)" in the Win98 device manager. It plays MIDI files using XG synthesis, and also allowed me to install Yahama's DS-XGS pure DOS drivers. The XG synth sounds off/wonky, and DOS support only partially works (no digital audio present, plus occasional slow downs and/or crashing) . I just opened it up and found it actually has a NeoMagic 256AV chipset for video and sound. So much for thinking I had a laptop with a DS-XG. At least it has a hardware OPL3.

Not sure about the AC-XG chips as I don't have cards with them.

I'm starting to think the AC-XG is nothing more than a generic DAC sound chip (i.e. no hardware synth, no DOS support) designed exclusively for Windows operations, much like today's laptop sound chips. I'd still like to know if there's anything unique about it. I'm still unclear if has a real hardware synth or not.

On the bright side, I have an AudioTrix Pro ISA sound card in storage, which if I remember right, has an OPL4 and a real XG synth on-board.

Apple IIGS wrote on 2021-08-20, 21:01:

The reason I asked about DS-XG, I also have a Sony VAIO PCG-N505VX (PII, 2003 era mini laptop) which reports "Yamaha DS-XG PCI A […]
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cyclone3d wrote on 2021-08-20, 16:28:

The DS-XG is a hardware assisted synth.

The samples are loaded into the computer's RAM, bit the synth part is integrated.

Pretty sure this is the main reason why the synth is not available in real DOS.

The reason I asked about DS-XG, I also have a Sony VAIO PCG-N505VX (PII, 2003 era mini laptop) which reports "Yamaha DS-XG PCI Audio CODEC (WDMI)" in the Win98 device manager. It plays MIDI files using XG synthesis, and also allowed me to install Yahama's DS-XGS pure DOS drivers. The XG synth sounds off/wonky, and DOS support only partially works (no digital audio present, plus occasional slow downs and/or crashing) . I just opened it up and found it actually has a NeoMagic 256AV chipset for video and sound. So much for thinking I had a laptop with a DS-XG. At least it has a hardware OPL3. That just leaves me to figuring out the AC-XGS in my NEC laptop....

Not sure about the AC-XG chips as I don't have cards with them.

I'm starting to think the AC-XG is nothing more than a generic DAC sound chip (i.e. no hardware synth, no DOS support) designed exclusively for Windows operations, much like today's laptop sound chips. I'd still like to know if there's anything unique about it. I'm still unclear if has a real hardware synth or not.

On the bright side, I have an AudioTrix Pro ISA sound card in storage, which if I remember right, has an OPL4 and a real XG synth on-board.

I'm not seeing anything mentioned about "hardware wavetable synthesis" in the marketing specs for the PCG-N505VX. It does say it has FM MIDI Synthesis and Sound Blaster Compatibility though:

However, the user manual says it has a YMF744B on page 87:

It would not be working at all with the Yamaha drivers if it didn't actually have the Yamaha chip.

The YMF-752 is an AC'97 codec, not a full PCI Sound chip. Like any AC'97 codec, it relies on the AC'97 digital controller on the motherboard, usually in the southbridge, and any compliant codec from any manufacturer is supposed to work with any compliant controller, versions of the standard notwithstanding.

AC'97 codecs are just the mixer, ADCs, and DACs of the sound solution, without much interesting going on internally. The link between the codec and the controller, AC Link, is a bidirectional serial bitstream of audio channels at exactly 48 KHz. I don't see how the standard would have room for MIDI data or OPL3 register accesses.

Therefore, at most, I think Yamaha could have provided the basis for a DOS driver to motherboard manufacturers and OEMs, with licensed OPL3 and SoundBlaster emulation code in it. Those manufacturers would then have to integrate that code with their own driver to speak to their AC'97 digital controller in the southbridge.

In other words, if there is a DOS driver for sound on your system, it would have to be supplied by NEC, who decided to pair the Yamaha AC-XG codec with the (presumably Intel) southbridge. Unless they felt it was an important selling point to have pure DOS sound support when Windows 98 SE / Windows ME have competent SB16 emulation built in, they would not have spent the time and money to create and support a DOS driver.

cyclone3d wrote on 2021-08-20, 23:33:

I'm not seeing anything mentioned about "hardware wavetable synthesis" in the marketing specs for the PCG-N505VX. It does say it […]
Show full quote

I'm not seeing anything mentioned about "hardware wavetable synthesis" in the marketing specs for the PCG-N505VX. It does say it has FM MIDI Synthesis and Sound Blaster Compatibility though:
vaio_pcgn505vx.zip

However, the user manual says it has a YMF744B on page 87:
pcgn505ve.zip

It would not be working at all with the Yamaha drivers if it didn't actually have the Yamaha chip.

Interesting! When I saw the NM2200 (NeoMagic 256AV) on the motherboard, I just assumed it was used for BOTH graphics and audio. Never thought there might be a YMF744 elsewhere on the board, it might just be hiding on the underside or covered by a daughterboard. If this is the case, I may switch over to the Sony for DOS games.

Assuming it does have a DS-XG (YMF744B), does "hardware assisted" mean it's a bonafide hardware XG synthesizer, with just the patches loaded from disk? Or is it software emulated? Wondering where the AC-XG fits into all this, is it a real XG or just emulated?

LightStruk wrote on 2021-08-21, 01:16:

The YMF-752 is an AC'97 codec, not a full PCI Sound chip. Like any AC'97 codec, it relies on the AC'97 digital controller on the […]
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The YMF-752 is an AC'97 codec, not a full PCI Sound chip. Like any AC'97 codec, it relies on the AC'97 digital controller on the motherboard, usually in the southbridge, and any compliant codec from any manufacturer is supposed to work with any compliant controller, versions of the standard notwithstanding.

AC'97 codecs are just the mixer, ADCs, and DACs of the sound solution, without much interesting going on internally. The link between the codec and the controller, AC Link, is a bidirectional serial bitstream of audio channels at exactly 48 KHz. I don't see how the standard would have room for MIDI data or OPL3 register accesses.

Therefore, at most, I think Yamaha could have provided the basis for a DOS driver to motherboard manufacturers and OEMs, with licensed OPL3 and SoundBlaster emulation code in it. Those manufacturers would then have to integrate that code with their own driver to speak to their AC'97 digital controller in the southbridge.

In other words, if there is a DOS driver for sound on your system, it would have to be supplied by NEC, who decided to pair the Yamaha AC-XG codec with the (presumably Intel) southbridge. Unless they felt it was an important selling point to have pure DOS sound support when Windows 98 SE / Windows ME have competent SB16 emulation built in, they would not have spent the time and money to create and support a DOS driver.

THANK YOU! That is exactly the information I was searching for, and finally puts closure on my decade long endeavor to turn this NEC laptop into a legacy DOS gaming machine.

I hadn't realized "AC" in the chip name referred to AC'97. In essence it sounds like there is nothing significant or unique about the audio in this laptop; in terms of legacy support, it's no different from any modern laptop. I suppose the only thing it does offer, is allowing the use of the XG software emulation synthesizer? Not based on its technical abilities, but the software does a checksum for the presence of a Yamaha branded chip and allows the software to run? Meaning it'd probably work on pretty much any sound chip, if it were patched to remove that checksum. I take it "DS" stands for Digital Synthesizer, or something else entirely?

Well, bottomline is I'm giving up on the NEC laptop with YMF-752S, It is not at all what I thought it was. On the other hand, the YMF-744B in my Sony laptop is likely everything I was looking for! (hardware OPL3, legacy DOS support and a hardware XG synth).

Apple IIGS wrote on 2021-08-22, 20:58:

I suppose the only thing it does offer, is allowing the use of the XG software emulation synthesizer?

I don't know if Yamaha restricted the use of its synthesizers with hardware checks or merely by only licensing it to OEMs that incorporated their chips. At least it's usually better than the software synth that Microsoft included with Windows, and you can experiment with sound fonts. You can use the XG synth in DOS games in a DOS box on Windows 98 SE / Windows ME; just choose the XG synth as your MIDI device in the Sound control panel and then choose General MIDI in the DOS game's setup.

LightStruk wrote on 2021-08-23, 13:57:

Apple IIGS wrote on 2021-08-22, 20:58:

I suppose the only thing it does offer, is allowing the use of the XG software emulation synthesizer?

I don't know if Yamaha restricted the use of its synthesizers with hardware checks or merely by only licensing it to OEMs that incorporated their chips. At least it's usually better than the software synth that Microsoft included with Windows, and you can experiment with sound fonts.

Question is, with the YMF-752, It is all purely software emulation, like the Microsoft synth? Just want to know if there's anything unique about the NEC laptop as far as XG synth is concerned. I probably won't want to hang onto it if it's no different from any other laptop as far as sound goes....

You can use the XG synth in DOS games in a DOS box on Windows 98 SE / Windows ME; just choose the XG synth as your MIDI device in the Sound control panel and then choose General MIDI in the DOS game's setup.

As far as the AC-XG, It worked for DOOM II (General MIDI/MPU-401 output) but not any other games I tried. Though it's all moot if the entire thing is software emulation, that doesn't interested me. The hardware assisted DS-XG, where patches are loaded from disk is about as far as I want to take it. I'm not big on sound emulation, I prefer the real hardware whenever possible (I can hear subtle differences).

Apple IIGS wrote on 2021-08-24, 01:20:

The hardware assisted DS-XG, where patches are loaded from disk is about as far as I want to take it.

On contemporary systems, the DS-XG cards are much faster than Yamaha's S-YXG50 software synthesizer which comes bundled with Final Fantasy VII. The soft synth stutters quite often during gameplay, while the DS-XG delivers a flawless experience in the same situation.

I'm not big on sound emulation, I prefer the real hardware whenever possible (I can hear subtle differences).

Here are some recordings from my Guillemot Maxi Sound Fortissimo (YMF744B-V), if you're interested:

• Descent - Main menu theme (General MIDI)
• Final Fantasy VII - Fighting theme (Yamaha XG)
• Technocrat (Yamaha XG)
• Geschichten aus dem Wienerwald (Sondius XG)