KT7AGuy wrote:

I'm about 20 years late to the game here. I recently finished Deus Ex and thoroughly enjoyed its use of 3D Positional Surround Sound while wearing headphones. (CMSS makes it even better.) To take advantage of this neat feature, your sound card must have an enabled onboard DD/DTS decoder and S/PDIF Passthrough must be disabled. 3rd-generation Sound Blaster Live cards (SB0220) and newer should have this. However, some OEM variants do not. OEM Audigy 2 ZS and X-Fi cards are notorious for lacking this feature.

I do not think it's true in this form. 3D positional surround sound has nothing to do with the audio compression format (AC3/DTS etc.) it also works with uncompressed PCM data (what's more it's better). 3D positional audio with older games only requires DirectSound3D hardware acceleration (and EAX or A3D). On more modern Windows operating systems (Vista+) unfortunately DirectSound3D hardware acceleration has been removed so workarounds like Creative's Alchemy or Realtek 3DSoundback or Indirectsound is needed. There are countless older games using 3D positional audio through DirectSound3D/EAX/A3D/OpenAl.
https://en.wikipedia.org/wiki/List_of_games_with_EAX_support
Also here on Vogons there are many topics about 3D audio or the restoration of it on modern systems (even Deus-Ex specific):
Restoring surround sound to Deus Ex and other games - should I get Sound Blaster MB3?
IndirectSound:
indirect sound

You shouldn't need the dolby surround setting in deus ex since its for outputting a pro logic compatible format if your sound receiver supports it, nothing to do with DTS and dolby digital as those are simply digital compressed output formats. Since you were running it under XP the hardware sound acceleration is still available which CMSS can use for the HRTF. Though I believe dolby's own HRTF technology, dolby headphone, is suppose to be compatible with sound sources like pro logic, so if you were using that instead it would actually work.

Thanks for the replies!

I'll have to go back and test this again, but I seem to recall the Deus Ex surround sound feature not working unless I also enabled the onboard decoder. When I get a chance, I'll test it and report back.

It is an interesting approach. I've never thought to try to use the sound card DPL decoder with a game.

Falconsoft, tgod,

I finally got around to testing Deus Ex again. You were both correct on this matter, so I wanted to acknowledge you and thank you for your comments.

DD/DTS onboard decoding settings had no effect whatsoever. What did have an effect was disabling "Hardware 3D Support" in the Deus Ex sound settings. Without that, it sounded just awful as your advice suggested it would.

My understanding of XP-era sound technologies is clearly lacking. I will do better in the future.