Recent queries and their answers:

Q: Why do cassette recorders have both a "stop" and a "pause" control? Aren't these redundant?

A: Tthe "stop" button stos the tape motion and also disengages the heads from contact with the tape. The "pause" button stops the tape but leaves the heads in contact with it. This way, you can adjust signal levels, which will be shown on the meters or other indicators, before starting to record. The pause control also lets you interrupt a recording while leaving the machine in the recording mode so that you can resume recording smoothly and noiselessly. For instance, if while you are copying a disc onto tape, you get to the end of side one of the disc and want to continue recording side two. When the record player's arm reaches the end of side one, you press the recorder's pause button. You flip the disc, start playing side one and release the pause button. Result: a smooth transition in your taped results.

Q: What is "microprocessing" and does it improve the performance of audio equipment?

A: Microprocessing is a kind of computer-like memory system, usually with digital readout, that has been introduced into some hi-fi components. For instance, it can be used to "order" an FM set to tune itself; it enables you to program a recorder to turn itself on and off at preselected times, and even to play certain portions of the tape; it lets you punch in a schedule for a turntable to play different bands of the same record side in any sequence you choose.

This feature adds to the cost of a unit, but it does not necessarily improve its audio performance -- except possibly in the sense of tuning in a radio station more accurately than you might yourself. At best, this is a marginal advantage. Microprocessing, in any event, does seem to have an appeal to many buyers.

Q: I've noticed square openings along the back edge of cassettes. They are not the same on all cassettes. Do they have some meaning for the user?

A: Okay, observant one: A square opening about 1/4-inch in from the side has to do with whether that cassette can be used for recording or is intended only for playback. If the opening is filled with another piece, the cassette may be recorded on. If the square space is fully open, the cassette cannot be used for recording -- the machine will not be switchable to the recording mode. This is a safety feature used on prerecorded cassettes to prevent their accidental erasure.

An opening along the rear edge of the cassette, but farther in from the side, indicates that the cassette is to be used with bias and equalization for chromiumdioxide tape. The opening permits some recorders to switch automatically to chrome bias and Eq/.

Q: What is the so-called "A" weighting in signal-to-noise measurements? It looks to me like a way of making equipment seem better than it really is.

A: "Weighted" measurements are those in which the "raw data" is modified in terms of some practical consideration relevant to actual use. The "A" weighted S/N figure takes into account the fact that our hearing does not respond uniformly to all frequencies. For instance, midrange tones will sound louder than bass tones even though both ranges have the same signal intensity. If the specified S/N for any audio component follows the IHF Standard, be assured it is a valid and reliable yard-stick.