[wulf]

I want to help design binaural 3D sound for a game that runs under Linux, but will need better equipment to really hear what I am doing. Reading these forums has made me interested in such headphones as the Audio Technica ATH-A900, Sennheiser HD595, and Grado SR-225.

My main worry is that such headphones are better quality than the sound most Linux-compatible sound cards can produce, and that the extra investment in headphones will only reveal more clearly the flaws in the sound generation. Support seems to have been withheld, for example, for cards like the E-MU 0404 and 1212. Are there supported cards which would make these headphones worthwhile? And which of the headphones I mentioned (or which others) will be best suited to my work?

A summary of my current criteria:

1. I am interested in matching the quality of a pair of headphones, a sound card to drive them, and an amp if necessary, that are suitable for casual reference work in writing algorithms to produce beautiful and accurate 3D imaging of sounds whose most important components are footsteps, doors opening, and the occasional burst of automatic gunfire.
2. Rough psychological limits on the purchase are around $200 for the headphones, and probably that much for the sound card and any amplifier combined; though I am open to strong arguments for adjusting these parameters either way.
3. The sound card needs to be supported under Linux.
4. Since I will be designing binaural sound, the sound card only needs to support two channels. (No 3D sound card has released support for Linux, I understand, so spatial cues must be generated in software.)
5. I want enclosed headphones that, while letting me hear the telephone ring, prevent nearby housemates from being distracted.
6. The headphones should be comfortable when worn for four hours at a stretch.

The sound cards supported by the Linux sound drivers I will be using are listed here; support exists for cards whose "Driver & Docs" column is not empty:

http://www.alsa-project.org/alsa-doc...php?vendor=All

Does anyone with more experience see any gems among the rough of low-quality audio hardware listed?

My current equipment, for the morbidly curious, is a pair of Titanium headphones from Radio Shack (received for Christmas years ago, probably $40 value), connected to old Gateway speakers whose amp faintly picks up local radio stations, connected to an old Sound Blaster Live! Value card on my PCI bus. (The headphones actually sound very good when compared to the Gateway speakers.)

 

[Mr.Radar]

Check out some of the higher-end Envy24-based soundcards (and check the ALSA compatibility matrix). They're pretty good and work with Linux (though to what degree I'm not sure) and most of them can work unamped. Also, check the A900's if you're doing gaming and don't want to distract people around you. From what I've read they seem to have a massive soundstage that's almost 3D (even without binarual processing). Though they tend to not be very revealing, so you might want to check out the Sony MDR-7506/V6 (not V600) too (which are quite revealing).

BTW, what game are you developing for?

 

[wulf]

Quote:

Originally Posted by Mr.Radar Check out some of the higher-end Envy24-based soundcards ... [and] check the A900's if you're doing gaming and don't want to distract people around you. ... BTW, what game are you developing for?

I will be attempting to write a binaural version of the OpenAL audio library, whose free Linux implementation seems to only implement simple panning in order to locate sound, which means that to perceive distance, the listener (or this listener, at least) must concentrate and determine whether a sound is louder in the left or right ear. America's Army is the game which has gotten me interested in improving OpenAL.

I think I will indeed go ahead and purchase the A900 phones. An Envy24-based sound card for Linux proved more difficult to find; the popular Audiotrak Prodigy seemed unavailable almost anywhere, and I could not determine whether Linux support exists for the Maya cards which seem to have replaced it. For the moment the M-Audio Revolution 7.1 looks like the best choice for me among the supported Envy cards, and can be had for less than a hundred dollars from Amazon.

I am purchasing Understanding Digital Signal Processing to improve my understanding of the necessary algorithms, and am referencing William Gardner's 3D Audio and Acoustic Environment Modeling for ideas about how to build the 3D audio image.

 

[Publius]

The AV-710 DOES seem to work judging from what I'm reading online. Given that, I would definitely go for that and ignore any other card out there. $30.

I wouldn't be toooooo worried about higher-order qualities of audio gear to do your development. What I would be concerned about is frequency response, because they may possibly mess up HRTFs. I'd almost be inclined to choose a headphone with a more quantified frequency response graph than one which sounds better but has an unknown frequency response.

The A900 is a great choice - I own one - but IIRC, response graphs are not included in the documentation and may be hard to get. they are out there though. (I'd expect the V6 to have a graph somewhere, but I don't have one to know (heck the A900 may have an official graph for all I know). Also Headroom has good measurements you could use for the headphones they sell.

The amp is important, if only to isolate obvious load issues from the setup. The type of amp is not. I'd guess even a Boosteroo would be sufficient for this application, or a cmoy. $50?

So assuming you get the 710, the A900, and a boosteroo or equivalent, you're down about $300, including shipping.

 

[Publius]

Also note that Unreal Tournament uses OpenAL and Q1 and Q2 could easily be modified to accomodate it. The technology might also be included in GPL'd windows games too.

 

[wulf]

Quote:

Originally Posted by Publius I would definitely go for [the AV-710] ... [with maybe even] a Boosteroo ... or a cmoy.

Since clean frequency response is desirable for my application, I had thought it would be a disadvantage to drive an inexpensive headphone amp with the inexpensive DACs in the AV-710 since they each would contribute an additional imperfect transfer function to the final mix. Mightn't the result be cleaner if I drive the A900's directly from the headphone out of a Revo 5.1 whose DACs, from what I have read, will be more linear?

 

[Publius]

Quote:

Originally Posted by wulf Since clean frequency response is desirable for my application, I had thought it would be a disadvantage to drive an inexpensive headphone amp with the inexpensive DACs in the AV-710 since they each would contribute an additional imperfect transfer function to the final mix. Mightn't the result be cleaner if I drive the A900's directly from the headphone out of a Revo 5.1 whose DACs, from what I have read, will be more linear?

All sound cards we're talking about (including the Live) have "flat" responses from 20-20kHz. More of a concern is being able to drive the headphones straight from the card - fortunately though, the A900 is known to do well even without an amp. So I guess the Revo would work too.

 

[wulf]

Quote:

Originally Posted by Publius All sound cards we're talking about (including the Live) have "flat" responses from 20-20kHz.

Then I am certainly confused about sound cards. Why do many forum readers prefer an E-MU 1212 over the AV-710 if they both have flat response curves?

[size=xx-small]Edit: an earlier version of this paragraph foolishly compared the 1212 to the Live! because I hit Save a moment before remembering that the Live only does 16-bit sound.[/size]

 

[Publius]

There are differences in distortion measurements, ie THD, IMD, dynamic range etc, but AFAIK most of the commented differences are purely subjective. You'd be fairly hard pressed to find an objective deficiency in one of the two cards that yields a provable difference in subjective quality.

 

[dandrey]

From my point of view, for you purpose, your SBLive plus something like V6 or HD280 is enough, more than that is overkill