Want to record 3D sound with PC

[scottdanzig]

Hey all, and thanks in advance for what help you can offer:

I chose a project for class and I'm trying to learn how to approach it. I basically want to synthesize 3D audio and also perhaps perform some analysis on it on the computer. I'm a poor college student just trying to finish up this class and graduate. I have a 1.7Ghz computer with an aging Soundblaster Live! card in it and I'm just wanting to record sound at different angles then replay them through headphones and maybe standard PC speakers. I know some stuff already... learned about HRTF's and how putting two microphones at each ear of a dummy head when recording provides a pretty good estimate for replicating the 3D sounds.

I'm wondering what I need to get to be able to start recording on my PC. 4 things flashed passed my eyes when looking into this. Binaural electret microphones, a power source for them (I've seen mention of batteries being sold with some microphones), a pre-amplifier, because cheaper sound cards, and I assume the Live! card is cheap enough, supposedly perform poorly at this, and lastly, whatever software I'll need to get a recording for each channel. I figure I'll play it back using a C or Java API, or Matlab if it allows that.

Can someone tell me what I really need to throw together a project where I'll learn something and also look like I know what I'm doing? Heh. Thanks again

 

[jrosenstein]

"3D" through headphones? sounds like stereo to me.

if you want to record more than 2 channels at a time, you'll need a soundcard with more inputs. and of course you need a preamp for each microphone you plan to use at once.

 

[James Argo]

Cakewalk did it for you...

Surround Sound with Sound Blaster Live 5.1 or Audigy card using Sonar and a 5 or 7 speaker system

Here is how you "activate" this cool and undocumented feature.

1. Setup 3 Virtual Main Busses in Cakewalk. I will call them VMB-A, VMB-B
and VMB-C. You do this by Clicking Options -> Audio. Then setting Number of Virtual Mains to 3. If it is already 3 you don't have to do anything. If it is more than 3 you don't have to do anything. If it is less than 3 you will need to restart Cakewalk after the change.

2. Create 5 audio tracks. Call them left front, right front, left rear,
right rear, center.

3. Record measure 1 the words "Left Front" on track 1, measure two record
"Right Front" for track 2 and so on.

4. Send the output of tracks 1 and 2 (N Front) to VMB-A. Send the output of tracks 3 & 4 (N Rear) to VMB-C. Send the output of track 5 to VMB-B

5. Play back your project.

If you want to use this in a real project I suggest you send your Front channels to AUX 1, rear channels to AUX 2 and center to AUX 3. Then send the output of all the AUX busses to only one VM. Then you can do volume and pan editing on the AUX bus and you won't need to do it for as many tracks.

But here, you'll need 4, 5, or 7 monitor instead of a pair of headphones...


Jaymz

 

[moskus]

Since you're the smart one, James...

I've tried this... But what do I do with the exported files to make it AC3 (or Dolby 5.1 or whatever) on, say, a burned DVD?

I've been looking all over the web for a cheap alternative, but it seems like I need an encoder in the $100000 class...

 

[AlChuck]

I think you guys are all missing the point... he's trying to do a science/engineering project, not record ordinary stereo or commercial surround sound.

I think the binaural mics you mention into the Sound Blaster should work just fine for your needs. You will probably have to dig around for the API commands to be able to talk to the sound card, but it should be standard Windows stuff (I'm assuming you;re running WIndows on the PC).

I remember doing a little looking around a couple of months ago and heard about this set of mics:

http://www.core-sound.com/mics.html

$230 is pricey for a school project but very cheap for a decent stereo micing system.

Alternatively you can look up articles on stereo miking techniques and use any pair of mics, I guess, in one of those configurations.

Here's an article:

http://industryclick.com/magazinear...easeid=5575&magazinearticleid=65366&siteid=15

and another

http://www.tape.com/cgi-bin/SoftCar...techniques.html?L+cassette+nqna2923+995498793

 

[knightsy]

Question for scottdanzig - Are you trying to synthesise the audio by a 5.1 type method or are you trying to do it in stereo?

If it's in stereo, then maybe try to rent a stereo mic (and stereo preamp) that is setup in a Blumlein configuration, that is, two figure 8 capsules in a coincident pair (at 90 degrees to each other). This apparently can produce some awesome results - on a Chesky test disc apparently there is a track where some percussionists walk into a room from behind you, hitting their instruments, do a couple of laps around you and then walk back out of the room shutting the door behind them! And all from just a stereo setup.

But it requires a lot of work to set it up - I personally haven't done it.