Tandy PZM microphone
Tandy's PZM microphone has become something of a legend in home recording circles because of its outstanding performance and very low price. It would be wrong to imply that it is perfect, but, used correctly, this microphone can produce impressive results in a variety of recording situations.
To those of you used to seeing microphones that look like a ball on a stick, the PZM must look a trifle unusual. It comprises a square metal plate, above which is suspended a small, electret microphone capsule. Being an electret design, power is required for the preamp and, to that end, a small battery box is located in the cable. The microphone will operate for very long periods from a standard AA battery and a slide switch selects between on, off and standby modes.
There's logic behind the unusual layout of this microphone, as it works on a slightly different principle to normal mics. The arrangement of the backplate reflects sound back to the capsule in such a way as to usefully add it to the direct sound arriving at the capsule. Not only does this increase the efficiency of the microphone but it also avoids the colourations encountered when a conventional microphone picks up both direct and reflected sound in a non-coherent way. For the microphone to work efficiently at low frequencies, it must be mounted on a surface large enough to reflect the long wavelengths involved — the metal backplate is far too small.
For optimum performance, the surface should be around one metre square, and this may either be in the form of a rigid board or, alternatively, the microphone may be fixed to a wall. The resulting pickup pattern is hemispherical and the sound quality tends to be pretty consistent regardless of the distance of the source from the microphone. This is in direct contrast to most conventional microphones, which tend to sound more 'confused' at long distances. The PZM is characterised by a bright, open sound and is useful in a variety of recording situations from acoustic ensembles to vocals; obviously two are needed for stereo.
Having put the good points, it must be borne in mind that this is a budget mic, and its Achilles heel is its relative insensitivity when compared to upmarket studio mics. The sensitivity can be increased slightly by using a 9V battery instead of the 1.5V battery supplied (solder on a clip and tape the new battery outside the case), but even so, very quiet or distant sounds require a lot of mixer gain which, in turn, brings up the level of background hiss. You'll also need to use a pop shield if using the mic for vocals, as it's quite susceptible to popping if used without. Despite its limitations, this really is an excellent microphone for general-purpose recording, while a pair provides the ideal opportunity to explore stereo recording techniques on a low budget.
£29.95 including VAT.
Any Tandy shop — see your local telephone directory.
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Review by Paul White
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