Crown Audio by Harman




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How can I make a Mid-Side (MS) stereo mic with PZM and PCC mics?

I plan to modify two Radio Shack PZM mics, wire them out of phase, and then generate an MS microphone array with the Crown PCC-130 half-supercardioid boundary mic.

I have since found on Ebay a second PCC-130, so I can modify this original design to include four mics, the plan being to generate several connection options to create Blumlein, MS, cardioid, and spaced omni, all from one single 2 x 2 foot sheet of mounted mics.

a) Are the capsules themselves in the PCC mics directional, or are its directional qualtities obtained through mounting a traditional electret mic capsule used in a PZM?
b) Why are there no technical notes discussing the use of PCC mics as music mics for field recording?
Jim Mastracco

Reply: The capsule in the PCC-130 (and any PCC mic) is directional (cardioid or supercardioid), and it becomes half-cardioid or half-supercardioid when mounted on a surface.

The PCC mics were designed for speech: conference recording, stage floor for drama pickup, and so on. Still, they might have a frequency response that is flat enough for music pickup. Regular omnidirectional PZMs have a wide-range, mostly flat response and work great for music.

If you use a PCC-130 for music pickup, the same considerations for boundary size apply as for PZMs. On the Crown website (www.crownaudio.com), you can click on Microphones, then at the top look for Document Library. Once there, scroll down to the Boundary Microphone Application Guide and download it. This guide gives lots of information on PZM and PCC theory and applications.

Like any mic, the PCC-130 picks up less reverb the closer it is to the sound source. Also like any mic, the sound you get depends on the mic placement relative to the sound source. To pick up an orchestra, you might start with the boundary panel raised about 12 to 14 feet, angled down slightly so its edge aims at the front row of the orchestra, and about 12 feet behind the conductor. Adjust miking distance to control the direct-to-reverb ratio.

If you wire two PZMs in opposite polarity and mix them together, they will have a bidirectional (figure-eight) polar pattern. However, all the bass will cancel, so you will need to apply lots of low-frequency boost to bring them back to a flat response.