Windows only emulates a Sound Blaster Pro and a MPU-401 interface but no OPL2/OPL3 based synth when using WDM drivers. What kind of system are you using?

I figured as such after doing some more experimenting yesterday, just more of the wonders of old PC sound quirks. I unfortunately assumed that the emulation Windows provides would also get you the FM synth. I'm not surprised though it makes sense.

I'm messing around with a HP t5730 thin client which as you could imagine has it's quirks i was assuming Windows would provide the necessary sound emulation for me to play all the DOS games i wanted from within Windows but without the OPL it's a bit of a deal breaker.

Have you checked out SBEMU? You can use it for Sound Blaster and OPL2/3 emulation under DOS and use AC97 or HDA for sound output.

Not sure if VDMSound fo Win9x have working OPL emulation.

Dan9550 wrote on 2023-03-08, 23:04:

I'm messing around with a HP t5730 thin client which as you could imagine has it's quirks i was assuming Windows would provide the necessary sound emulation for me to play all the DOS games i wanted from within Windows but without the OPL it's a bit of a deal breaker.

I've been also playing with T5730 and as Kamerat suggested, you need to give a SBEMU a go. It works perfectly with T5730 and you can get almost perfect OPL3 emulation with DOS for majority of the games.

have you tried the mpu-401 sound option in your game? i have a laptop with an ess es1978 which has no hardware fm synth, but both vxd & wdm win9x drivers. with wdm drivers i can use the microsoft software synth (must select it in windows midi mapper) licensed from roland that ships with windows at address 0x330. i also experimented with the vdmsound win9x alpha to emulate an opl3 and had some success when i used the vxd drivers (never tried wdm) for the sbpro part and vdmsound only for the fm synth (assigned each different resources).

When I set up my WIN98SE machine especially for DOS games, I knew the sound wouldn't work because it's onboard and sharing IRQ11 - which DOS games know nothing about. So I installed a spare AWE64 to the usual addresses to suit DOS, and all the games worked as expected.

Robbbert wrote on 2023-05-31, 21:57:

When I set up my WIN98SE machine especially for DOS games, I knew the sound wouldn't work because it's onboard and sharing IRQ11 - which DOS games know nothing about. So I installed a spare AWE64 to the usual addresses to suit DOS, and all the games worked as expected.

If you've got WDM drivers then the IRQ used by the soundcard doesn't matter, the Soundblaster & MPU401 emulation in Windows 98 DOS-box will work with just about any IRQ that's specified. So on my Sony Z600TEK which will only work with WDM drivers, the IRQ is 9 for the soundcard and cannot be changed.
But with the soundblaster emulation built in, games accept and work with IRQ 5, DMA 1.
This does require that the computer is using WDM drivers though so there's no other legacy sound support installed/running. It also requires that the computer is booted *without* specifying "SET BLASTER=", otherwise that also disables the soundblaster emulation in Win98.
There's no OPL / FM sound with this method, but the MPU401 it provides is good for most games.

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That's only for Windows as well, since it's Windows 98 I was able to set up a boot menu. On the Vaio Z600TEK, I can choose at boot whether to boot into Windows and use the SB+MPU401 emulation, or boot into DOS and run the Yamaha YMF744's init software to get SB emulation in DOS, which gives me OPL3 but not MPU401/MIDI sound.