Alright, /g/, I'm trying to build a pair of over-ear headphones from scratch. They are to be circumaural. They will include 4 drivers per cup. Where should I source the parts? Money is no object.
I'm not sure how to proceed in a multiple driver circumaural. Simple lumped element models break down in the highs of a headphone, the most difficult parts to tune and control for, and multiple parts don't make it easier.
I could sort of envision a two way coaxial driver, why the 4 drivers?
Individual drivers in a speaker can't manage high SPL across a broad range of frequencies. Given the proximity, this is far less an issue for headphones.
Normally, you try to isolate the backwave somewhat even in an open backed headphone. Your justification for not doing so is?
Look on digikey or mouser. You can also order drivers from audio technica for around $60 for most models. Take a look at orthodynamic tweeters while you're at it, some make great headphone drivers.
I haven't seem many multidriver dynamic headphones, probably because imaging would be messed up. With speakers, the different drivers are several meters away from the listener, so you won't notice that the drivers are several centimeters apart. With headphones the drivers are mere centimeters away from your ear, you'll easily notice that the different frequencies are coming from different locations. With BA iem's you don't get this problem because the sound is directly piped into the ear. You could make it work by artificially enlarging the soundstage, say you have your "tweeter" closer to the front and your "woofers" closer to the back. If you crossover low, maybe around 500Hz you could make the soundstage sound deeper than with vocal tracks. However if you don't do this careful, it will sound really disjointed as the different tones from the different instruments will be coming from different physical locations.
Another downside is the impedance of all those drivers. Depending on how you wire and crossover them it could have a drastic effect on SQ.
The project isnt a bad one, you just need to read up into acoustic theory a bit more.