When I updated my system with a modern motherboard (without DDMA support), I found my ES1938S-based audio card is no longer able to produce any digitized sound even though it can still produce music. The board I'm currently using is a GA-M720-US3 nForce 720D motherboard. As far as I'm concerned it seems to be the problem with IRQ... Looks like on modern motherboards (where ISA functions, DDMA, and so on are no longer supported), IRQs vital for audio cards to work in DOS (5,7,9) are likely be occupied by something else, and it seems there are something beyond the IRQ problems since changing IRQ assignments in DOS will not make the audio card work properly. I fear it's no longer that simple as some early DDMA-complaint chipsets... as if the network card want that IRQ you cannot move it away since it's onboard. IRQ seems to be a complex thing itself... and with APIC it becomes more complex (as IRQ can go beyond 15 using APIC). What I can conclude is that playing FM music using the FM synth on the sound card simply needs a usable DMA, and DDMA, even ESS' TDMA, will cover that perfectly. The digitized sound, however, relies on a usable IRQ, and it seems nearly impossible on modern motherboards. I don't know whether there is a way to emulate a usable IRQ environment for these ESS sound cards to produce digitized sound properly... (AFAIK ESS' TDMA is the best way to make a usable DMA. It only consumes a little base memory, usually about 1K, for TDMA, and a specific chipset is not required for TDMA to work.) Actually on ESS' old webpages found in the Internet Archive I can still see a configuration tool for ES1938/1946. It can no longer be downloaded from official site, but the one I found in DriverGuide will show "Unable to find ES1868-based chips." when I run it. I don't know if DOSBox's emulations can be ported to run on pure DOS as long as the system has adequate memory and good EMS/XMS manager for it... It looks like there are still ways for sound being supported via a DOS extender or something... Even though DOSBox has made a great progress on emulating it, I can still feel some differences. For some apps and games, DOSBox suffers heavy lags (and even some games don't lag in graphics I can still feel some latencies in sound, as sound are often processed about 0.5 seconds later), that's the main reason I don't use DOSBox for legacy programs very often. Also, DOSBox cannot create a native DOS fullscreen display environment, which I can feel the screen quality is not as good as a pure DOS environment. For now, I still keep the card on the system for its FM MIDI playback, while I use the onboard sound for Audio playback in Windows or Linux... but I'm unable to connect the two soundcards together so I don't need to switch the speaker cable from the HD audio to the sound card manually when I want to hear MIDI... (I don't know how can DXDIAG send sound from sound devices not directly connected to the speaker into the speaker and play the test sound through it. But the way DXDIAG do seems to indicate it's possible to do this.) If anybody knows how to make digitized audio from ESS-based audio cards work flawlessly in DOS, or if anybody has ever done it before, please tell me.

UPDATE: I found that Aureal Vortex AU8820 worked fine in DOS (set on IRQ 9 which was only occupied by ACPI controller in my case). Although it's less compatible than ESS chips, and its music is not as good as the music played from ES1938... Actually ESS' TDMA technology was based on Aureal's DOS support, and TDMA made the sound card supports legacy DOS apps more natively. So that what is really needed to make ESS chips work flawlessly, is a tool to manually configure the ESS chip to use a new IRQ instead of 5 and 7 which were easily occupied by other devices like Display, USB. (AFAIK IRQ 5,7,9 are the only IRQs supported by most games and will work fine if unoccupied, and some may crash when used IRQ10) In my case, the IRQ5 and IRQ7 are all occupied by Network Controller, PCI-E Video Card, SMBus Controller and some of the onboard USB ports). So at present, despite its bad music quality and heavy base memory consumption (about 35K), AU8820 (and probably AU8830) seems to be the only chip I've tested fully functional in modern systems in DOS thanks to its excellent SBPro emulation and the capability of manual IRQ setting. By the way, I still don't really understand why Distributed DMA technology was completely phased out after about 2003 or 2004... IMO it didn't seem to be anything troublesome to modern systems, and I even read that DDMA performs better than the old ISA-style DDMA...

Another update: Unfortunately, AU8820 cannot play digitized sounds properly after certain tests. The sound simply loops, but so far it's the only sound card I've tested to be at least able to produce digitized sounds. Creative Sound Blaster PCI and Live! may work but I no longer use them since they uses complete SB16 emulation that requires EMS and only EMM386 (QEMM will reboot without notice) is supported. I knew that YAMAHA cards rely on DDMA, but somehow I found my YMF744 continues to function in DOS with a DMA 1... (Just with the Sound Blaster 8 BIT sound testing grayed out, other tests fine including the FM) The result is the same as the ES1938... no sound, just music. And when using YMF744 I have to set STACKS=12,256 to make it work (or otherwise it will tell me stack overflow). But whatever it is, it produces genuine OPL3 music, and with only music enabled, most games will function fine. And probably due to these reasons, programs like MPXPLAY will crash in the same manner (the program will crash when trying to play digitized sound including MP3). And one more thing: Looks like the problem persists on all old and current nForce chipsets since the board I'm using is an nForce 720D. I'm not sure whether other brands suffer the same problem... (AFAIK onboard network controller, SMBus Controller and PCI-E slots on nForce-based motherboards seem to occupy IRQ5/7 very aggressively, and there are only ways to change IRQ settings on a PCI slot while it cannot really move an onboard device away from it) DOSBox is the currently best solution for sound (and what actually prevented DOS games from playing properly IS ONLY SOUND), but not for anything else... (such as graphics, playability, and so on).