Source Engine Games - How To Enable Hardware Sound

Soldato
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Here's one for those of you with X-Fi (and possibly Xonar and other) cards who have been thinking positional audio in Left4Dead 2 and other source games isn't as good as it could be - Especially if you're using surround sound (including headphone based surround like CMSS-3D Headphone or external virtualisation on reciever). I've just tried the tweak and found it significantly improves my ability to hear the location of in-game opponents - especially at close quarters (other cards may not have as marked a difference as X-Fi due to differing features).

**Edit: Game audio doesn't work perfectly in L4D2 with hardware sound. A lot of the in-game music doesn't seem to work**

Most source games use the Miles Sound System - a software based API that directly programs each channel of your sound system. That means none of the more advanced features of your soundcard are utilised.

Before enabling DirectSound3D in a source engine game X-Fi users will need to run Alchemy and point it to the location of your game's .exe. For L4D2 in Windows 7 this is C:\Program Files (x86)\Steam\steamapps\common\left 4 dead 2\left4dead2.exe. Set Buffers to 5 and duration to 10. (If you use a Xonar this might work if you just turn on DS3D-GX, Realtek follow a similar process to Alchemy with 3DSoundBack, C-Media enable XEar3D etc).

Best results will come from ensuring that the X-Fi is in game mode before launching the game. CMSS-3D options for MacroFX and Elevation Filter should be set to Auto (options not available for 5.1 or 7.1 - see later).

Set the audio options in game and Windows to match the speakers / channels you intend to use.

Then to actually get DirectSound3D working you will need to run a console command. In L4D2 you need to first enable the developer console in the in-game Options. Start a campaign (preferably single player) and bring up the console (usually the ` key). Then enter the following: "snd_legacy_surround 1" (if you have any problems repeat the process with "snd_legacy_surround 0" to turn it back to normal). You will get a message saying 3d sound activated.

At this point my game went silent and I needed to restart it. Once back in game - Voila! The superb positional sound I'm used to for hardware based games running in L4D2 - Marvellous!

If you run a surround sound system or CMSS-3D Headphone with an X-Fi I would advise sticking to 4 channels maximum. This allows MacroFX and Elevation Filter to work, which improves 3D positioning considerably when using hardware sound. On any other current card - I don't expect this will make any difference so feel free to go with 5.1 or 7.1.

Just stumbled across this as it bothered me that I didn't appear to be able to hear close quarters directions very well in L4D2. That reminded me of AngelRex's comments regarding CSS and Dolby Headphone so I thought I'd have a play and see if I could change anything. Turns out there's a whole other fully-functional audio engine under the hood. Very nice! Having said that I'm not convinced that environmental effects are as good with hardware as with the Miles Sound System. Maybe I can confirm with further testing.

I've confirmed this works on an X-Fi Prelude in Windows 7. It might work on any soundcard that has legacy support for DirectSound3D (Xonar, Realtek, C-Media or other Creative such as Audigy Series). Please can you post to confirm if you get it working and I'll update the original post.

For anyone using the standard 2 channel headphone mode - I would stick with miles rather than hardware as the Miles Headphone mode is pretty advanced. If you use CMSS-3D Headphone or Dolby Headphone it's definitely worth doing.
 
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I'll just add that my initial test was with an external Dolby Headphone receiver (SU-DH1) and 4 speaker CMSS-3D (vs 4.0 / 5.1 in Miles Sound System). Was using Goldring DR150s. I'll try with CMSS-3D Headphone later, as it will be more representative of X-Fis in general.

I will say that I find the Miles Sound System stereo headphone mode pretty good for positioning but find the various filters it uses rather artificial sounding.
 
Product Specs (SoundXPlosion):
Technical Specifications

* Subwoofer: 40mm Ø, 2 pieces with 100mW @ 4 OHMS
* Front/Rear: 30mm Ø, 2 pieces with 30mW @ 32 OHMS
* Centre: 30mm Ø, 4 pieces with 30mW @ 64 OHMS

Frequency Response:
* Subwoofer: 50-400Hz
* Front/Rear: 250Hz-17KHz
* Centre: 180Hz-14KHz

Odd specifications there but it's refreshing to see them published for a multi-driver headset. Do they plug into the soundcard directly or have a dedicated amp?
 
OK - a little more to report. With up to 4 channels this works well but 5.1 and 7.1 seem to be broken. If I enable either the in game music stops working.

A word of caution - although direction seems to be improved some sounds are quieter - notably footsteps. That could be a deal-breaker for some.
 
A further note on L4D2 - with hardware sound enabled some of the in-game music doesn't work. Shame really...
 
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