Long, long ago, in a city far, far away I was a college student. I was studying media arts, and somewhere along the line decided to do a paper on an emerging new approach to recording called Ambisonics. This is a most elegant approach to recording conceived by Michael Gerzon, a brilliant, English mathematician. Beyond simply the theoretical, Gerzon developed a microphone in support of his idea, which became the Soundfield Microphone.
How I lusted after a Soundfield microphone, and the four-channel recorder necessary to make field recordings. Manufactured in England by Calrec, the Soundfield microphone cost upwards of $10K on its own. As a not quite starving, but certainly hungry student, this was far beyond my reach.