Realistic PZM Microphone Pair

The PZM is very similar to the boundary mics with which they share their appearance. While PZM mics are boundary mics, not all boundary mics are PZMs. Invented in the late 70s and produced by Crown, and in their low cost incarnation by Tandy/Radio Shack, the PZM mounts an electret capsule just above a flat plate and, placed in this "pressure zone", the mic benefits from a "free" 6dB rise in level due to its placement at the boundary. The size of the boundary on which the mic is mounted affects the frequency response and given that I often used to use these mics "free standing" with just the 5"x5" steel plate it's not surprising that they were bright. In fact these mics had a positively stratospheric frequency response. This goes some way to explaining why they were so popular 20-30 years ago but have fallen out of favour more recently.