Create spatial sound illusions that work in headphones and speakers

Question

I am curious if anyone has experience making fairly realistic / hyperrealistic spatial audio illusions (for instance the impression of someone circling around your head) that work both with headphone and speaker monitoring. Binaural techniques / HRTFs seem to work best with headphones, but break down very significantly in speakers. However, stereo panning sounds really awful in extremes on headphones. I've found the duplex panner which I have been using a lot and really helps with the stereo panning problem, and I've been using EQ and reverb intuitively to give a sense of position, depth, and space, but I wonder if there are other techniques or approaches to this strange problem floating around out there.

The goal is not necessarily to be 100% realistic, but rather to surprise and please a listener to be suddenly immersed in a spatial sound experience. So it's more about feeling good, exciting, and spatial.

This is for podcast/radio style production, so it's about equally likely that someone will be listening with speakers (even car speakers) or headphones, and the goal is to give the best spatial experience across as many listening scenarios as possible.

Excited to hear how anyone has approached a similar problem!

Answer 1

ReaSurround in Reaper is pretty good, after reading your question I did find this post in the Reaper forums that does pretty much exactly what you want.

http://forum.cockos.com/showthread.php?t=133619

Check out the demo file he created, it definitely simulates that soundstage well.

I started playing around with it a bit, and it's not super intuitive, but I was able to just mess with it for about 15 minutes and get a similar result.

Answer 2

When I was studying computer music at Eastman back in the late '90's, this is something that was being actively developed by the composing community. The best effects rely on understanding psychoacoustics. My teacher Alan Schindler was writing code along these lines in CSound, a free programming language developed at MIT, which is nice because it is totally open-source and there is a large community of people still actively writing in it. You can get very good effects by taking into account when signals reach one ear versus the other, how quickly frequencies decay based on distance travelled through the air, and reflection factors for various surfaces, adding in the reverb effects to model certain shaped rooms, outside environments, etc. Panning alone really can't do this sort of thing!

Schindler wrote an opcode in CSound that we all used to make things appear like they travelled through your head, suddenly shot 40 meters up into the air, and so on. It worked with as few as 2 speakers, although the effects were best if you were located in the "sweet spot" between them.

Although I haven't been in that world for a while, I'm pretty sure all the thinking that went into it is something you could still find in a CSound forum or by researching Schindler's work. Also, IRCAM is an obvious place to check out.

Answer 3

Several factors go into spatializing sound: 1) amplitude - sounds that are far away obviously sound quieter than those nearby.

2) panning - again, fairly obvious. if a sound is louder in one ear than the other it sounds as though its coming from one side of you. stereo widening can also produce interesting effects

3) eq - very, very important in sound spatializing sound and not so obvious. Bass frequencies travel through matter better than higher frequencies so a distant sound will sound bassier than a close one. Sounds like you already knew this.

reverb can also help create a sense of space as you mentioned. Its tricky because spatial effects will be obvious in headphones and subtle over most speakers. I'd focus on very patiently automating amplitude, panning and eq to achieve convincing effects. They interact with one another in unexpected ways.