AES Convention Papers Forum

This paper introduced the pressure zone microphone.  If a pressure microphone is placed near a flat boundary, it goes from being omnidirectional to being directional, and it develops a rising response above a certain frequency (set by the distance from the boundary).

This was first taken advantage of by Electro-Voice in the 1960s with the "microphone mouse" but the idea pretty much died out.  It was still very useful for avoiding echos and comb filters caused by room reflections where a microphone could be mounted on the reflective surface.

The technique became popular though in 1980 because at the time it was easy to make inexpensive condenser capsules, but hard to make them directional and hard to make them have a flat top octave.  So the boundary configuration was a perfect fit to fix problems of that era.

Later on people become a little too enthusiastic about the principle and it became a bit overused and developed something of a bad name, but it is still extremely useful although the zeal of this paper should be taken with a bit of a grain of salt.