Project #2 - Quadraphonic Headphones

For the couple of years I have tinkered with surround sound, I have spent more time dedicated to recording rather than on playback methodology. So, for my final project, I decided to build a built a set of quadraphonic headphones using the transducers from 2 sets of Koss headphones.

There are a few entries on the Internet about attempts at making quadraphonic headphones, many have additional circuitry for phase shifting signals rather than correct positioning to simulate speaker positions. It appears that most were developed in relation to the quadraphonic playback which never really made a large impact on the market, and I found no entries related to ambisonic recording playback and headphones.

Some of these devices used a single transducer on each side, others use a pair. As well as I could tell, the 2-transducer units placed both on a flat plane. My version angles 2 transducers at approximately 45 degrees to the listener's head and 90 degrees relatively to each other. My thought is that the pinna (outer ear) would effectively shift the phase if the rear transducer was in the proper position.

I chose to use the smaller transducer for the rear for a better match to the size of a typical pinna. Furthermore, I positioned the front transducer slightly closer the the listener's head than the rear transducer. Ideally both transducers would be from the same model of stereo headphones, but my parts bin did not provide such.