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Discussion: PC Gaming Audio

post #1 of 5
Thread Starter 
I wanted to create this thread so that gamers and such can get questions answered, and so that I can get a question or two of my own answered. A bunch of them have been cropping up, so I figured I'd share some of my own knowledge and ask others for their input.

Receivers with Audyssey: Audyssey does not work with multichannel input. if you are going from your nice gaming sound card via direct analog to the receiver, all of those setups and measurement things make no difference. For this reason, you would do well to have a "home theater oriented" sound card.

Does this product exist? Something with per-channel crossover, equalizer, etc? Aside from HDMI for 5.1/7.1+ and optical/coax +DDL/DTS-Connect, I see no way to get multichannel output from PC to receiver.

Another thing I have learned: Zone2, in the vast majority of receivers, only works with analog input sources. If you have your xbox playing tunes over optical or HDMI and want it to output via zone2 instead of mains, you are SOL.

A question I had in particular: How do you know what sound format a game is meant for? Movies often tell you when they have a dts soundtrack or a dolby soundtrack. Do games tell you if they were meant for 2.0 vs if they were recorded in 2.0 and upscaled to 5.1/7.1 vs if they were designed with a multichannel audio setup in mind?

Skyrim has a decent set of multichannel effects, but Darksiders (as far as I know) doesnt. Enabling dts-connect on my sound card yields no real solution.

For computer audio via HDMI, there seems to be no way to do a purely audio HDMI signal. IE if I am using DVI to monitors and want HDMI to receiver, the receiver WILL be recognized as another monitor. On a similar note, the HDMI cable, from an audio perspective, seems to be always treated as multiple PCM streams.

For example, lets set windows sound to 5.1 mode, and use HDMI to go to the receiver and play a 2.0 source file. The stream the receiver gets is actually 3/2/.1 rather than 2/0/.0. If you use WASAPI, it will receive the proper 2/0/.0 stream though. Does this mean that every time i want to switch between 2.0 and 5.1 and 7.1 audio I need to go into windows and change my speaker configuration in order to get the right stream? Theres no such thing as system wide wasapi unless you are using something like ReClock, which can be a pain to set up correctly. Even with reclock, the audio stream is treated "incorrectly". You might get a 3/2/.1 stream while playing 2.0 but the music only comes out of the L and R channels like its supposed to. Its just very annoying to play a 2.0 file and get a 5.1 output going to the receiver.

Lets get some tips and discussion going!
post #2 of 5

I don't use HDMI at all (don't have the equipment or the need for it), so that complicates things for me.

 

However, here's what I can tell you:

 

-The early days of 3D audio, back when every gaming computer was expected to have a sound card with a high-performance DSP on it specifically to take the load off the slow CPUs of the day (remember, 200-500 MHz was the norm then!), had it so that games that used the DirectSound3D API from DirectX 5 onward (and, later, OpenAL) simply forwarded the 3D positional coordinates of all the sounds in its virtual space to the audio device, which then decided where and how to play back these sounds according to their positions.

 

The beauty of such an approach is that it is NOT fixed to any speaker configuration. You could, in theory, make use of a whole Dolby Atmos theater's worth of speakers if you wanted to!  And of course, us headphone users get treated with binaural mixes that put our heads in the game rather than some virtual home theater speaker system approximating a game environment.

 

-Starting around 2007, the game development industry at large started moving to software audio APIs and middleware like XAudio2 + X3DAudio (I'm still upset at Microsoft for replacing DirectSound3D with that crap), FMOD, Wwise, etc. Since it's all mixed by the CPU, the experience is generally consistent regardless of audio device used, but 7.1 speakers worth of positioning are all you get. Anything beyond that is an impossibility due to their shortsightedness.

 

-Because the most common adopted approach for surround speakers on PC was to simply put more 3.5mm TRS jacks on sound cards for the surround channels, thus sidestepping the bandwidth limitations of S/PDIF, PC games are designed to output all their channels' final mixes as PCM, unless the audio middleware has the relatively rare option of an on-the-fly Dolby Digital or DTS mix, sort of like Dolby Digital Live or DTS Connect on a sound card.

post #3 of 5
Thread Starter 
One thing I really dislike is when my source file is being output in a non-source file format. For example, if I turn on DTS-Connect and feed it a 2.0 source, the sound card itself will upmix all of the 2.0 to come out of all 5.1 channels. That is extraordinarily annoying to me. (over s/pdif, anyways). So I would ideally like a way to tell when my video games' sound files are enabled for 5.1 vs when they are simple 2.0 mixes. For torchlight 2, I simply went into the steamapps folder and found a bunch of stereo .ogg files, so that was easy enough. That becomes a headphone/2.0 game. What about other games? How do I tell with the other ones?

And is there any way to keep that source file integrity? I feel like something like reclock or some sort of wasapi type thing might be my only option for that. But using wasapi on a 5.1 flac file, for example, bypasses dts-connect, meaning HDMI audio is my only reprieve. arghhhhhh
post #4 of 5

So what you're aiming for here is total bit-perfectness, and NO stereo upmix.

 

But here's the thing: video games are NOT simple collections of recordings. Things have to be mixed and reproduced on-the-fly from a number of sources, some mono (usually point sound effects used within a 3D space), some stereo, sometimes even surround (though I've never heard of a video game actually having a soundtrack mixed with surround in mind). You can't just treat them like you can music and movies, where you can just set them to play back bit-matched and call it a day; if anything, the game engine itself has most likely demolished any sense of bit-perfectness in its internal mixing.

 

Things actually get worse when you're working with older PC games and you're an audio purist; there have plenty of debates on VOGONS and elsewhere about exactly what sound card to get for which games, down to the exact revision of, say, a Sound Blaster Pro or Roland MT-32. Games made in the EAX days are often subject to which sound cards reproduce EAX properly; they say that Aureal Vortex-chipset cards and most others get it wrong, and only a Sound Blaster Live! or Audigy (2/4) running under Windows 95/98 using the VXD drivers and NOT the WDM drivers will sound as intended. Yes, it's that crazy.

 

As for figuring out the intended output? It's hard to say, since I don't use speakers and don't use HDMI output. I just go by the general rule of "turn CMSS-3D Headphone on when it's a game that benefits from surround sound, and turn it off if the game wouldn't make use of it at all to preserve audio quality".

post #5 of 5
Thread Starter 
Doesnt that end up just dissolving into an even more simple rule? Namely, if the camera is centered and locked around a single character as in first person shooters, use headphones+3d effects or dts-connect/dolby digital live. If the game is a fixed view camera type thing where positioning is not important like in Civ5 or Torchlight II, use stereo.

For speakers+HDMI, the output seems to be highly dependant on windows settings. I can start a video with a 2.0 stereo file in VLC and it gets passed through as 5.1. Even more annoyingly, for many of the guides and whatnot out there, the PCis used to decode dolby digital and DTS rather than bitstreaming to the receiver. I dont know which is supposed to be preferred, but I also have yet to find a user friendly interface that simply tells me what the computer is trying to do. IE "im playing FILE at FPS. using CODEC for video and CODEC for audio, converting both to their native settings" or "sending audio via S/PDIF".

For headphones, things become insanely easy. I dont bother with the 3d effects and just stick to pure 2.0. That ends up giiving me a good enough sound. For skyrim, I like 5.1 as positioning is very nice.

this whole thing sounds to me like we are in some sort of half thought out state of audio for games, where 2.0 and 7.1 make no difference aside from virtual surround settings and sound card mixing.
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