How should I use discontinued PZMs to mike a choir?
My church has two PZM-6LPG mics mounted above and at the center of the choir. One is mounted without the metal plate on a piece of Plexiglass hung at about a 30 degree angle above and ahead of the choir. The other is mounted on a metal plate screwed to acoustic tile directly above the back row. Both mics have a PX-18B interface between the mics and our mixer. I have some questions below.
The replies to Marty's questions are in italics.
1. How can I get a data sheet on the PZM-6LPG? The PZM-6LPG was introduced in 1980, and there have been a lot of improvements since then. The closest data sheet we have to the PZM-6LPG is the PZM-6R.
Click here for data sheet (798K pdf file).
The specs for the PZM-6LPG are the same as for the PZM-6R, except that the PZM-6LPG is gold and requires a PX-T, PA-18, or PX-18 interface to work. The interface is built into the PZM-6R (now the PZM-6D). Also, the sensitivity of the PZM-6LPG is about 6 dB less than the PZM-6R or PZM-6D.
2 Is the PX-18B required? Yes, with the PZM-6LPG. Or will the phantom power run the mic properly without the interface? No, not with the PZM-6LPG. The PZM-6R and PZM-6D have built-in interfaces, so they work directly off phantom power.
3.How can I ensure that the XLR plug on the PZM-6LPG is wired properly? I am assuming that the input to the PX-18B from the mixer is standard XLR wiring (
1 Shield, 2 Hot, 3 Cold). Yes. XLR pin 1 in the mic is shield, pin 2 is B+ from the PX-18, and pin 3 is audio and B- from the PX-18. Be sure that pin 1 in the mic connects to pin 1 in the PX-18, pin 2 connects to pin 2, and so on.
4. How can I improve the microphone mountings to increase choir volume or would it be better to replace them? It would be better to replace them with the Crown CM-30 or CM-31 choir mics. They are small, supercardioid condenser mics with very good gain-before-feedback, and a more natural sound than those older PZMs. The CM-30's electronics mount in an electrical outlet box near the ceiling and has screw-terminal connectors. The CM-31 has a standard XLR connector. They are available in black or white.
5. Would these mics (PZM-6LPG) work better for a piano? Yes, definitely. Tape them to the underside of the lid, with one mic over the treble strings about 8 inches horizontally from the hammers, and the other mic over the bass strings a couple feet from the hammers. You might need to close the lid to reduce feedback. If you do so, the sound can get a little tubby, so you might want to EQ in a dip around 300 Hz or so.