"TWICE THE SPEED. Twice the performance." So reads the brochure describing the new two-speed cassette recorder introduced by the firm B.I.C. (no relation to that other BIC).

While my tests of the top model in this series (the T-3) do not add up to "twice the performance" at 3 3/4 inches -per-second as compared to results at the conventional cassette speed of 1 7/8 i.p.s., they do indicate notable improvement at the faster speed. In fact, the audio response and the wow and flutter measurements of the B.I.C. T-3 are the best I have yet seen in a cassette recorder priced under $1,000.

The T-3 is not exactly low-priced; when it was first announced last summer, its cost was $500. Since then the price has risen to $530. It still is a very good buy, all things considered. The T-3, by the WAY, IS A THREE-HEAD MACHINE (SEPARATE HEADS FOR ERASE, RECORD AND PLAY). A twohead version, the T-2, which otherwise is very similar, costs $350.

Where costs have been cut, apparently, is in the transport mechanism. While it is very competent, at least in my tests so far, it is hardly as "sophisticated" as some of the solenoid-feather-touch-control systems found on other cassette decks. The keys on the B.I.C. are reminiscent of older cassette machines in their relatively stiff action, and the lack of the facility for "fast buttoning" (changing directly from one mode to another without any need to press the stop button).

The B.I.C. deck also lacks a mixing feature -- you can record live from microphones or via the line input from other sources, but you can't do both at once and combine the two inputs.

But what this model does have in the way of audio competence more than makes up for its limitatons. It is, of course, the first (and so far only) cassette recorder that offers the option of operating at both the standard cassette speed of 17/8 i.p.s., and at the faster speed of 3 3/4 i.p.s. The ill-fated "Elcaset" format also ran at 3 3/4 i.p.s. but it required an entirely new size cassette. The B.I.C. machine handles the same cassettes you would use for any other cassette deck and so at least in this regard, while it represents something new in this format, it does not imply any drastic major change or "sudden obsolescence." Operating it at the faster speed is no different from using any cassette deck at the standard speed. The tape runs at twice the speed (and of course you will be using twice as much tape as before for a given length of program).

But the performance will make audio fans look up. At 3 3/4 i.p.s., using either "normal" tape or the high-bias "super tapes," freqency response runs from 20 Hz to beyond 20,000 Hz within plus-or-minus 3 dB. This has to be the best yet measured on a consumer-grade model. With the Dolby-B switched on, signal-to-noise comes to an unbelievable 69 dB and 67 dB respectively for super-tape and normal tape. The wow and flutter figure is equally unbelievable at only 0.025 percent. Distortion at normal recording levels never tops 1 percent. Recording heardroom is plus-7.5 and plus-11 for both tapes, respectively.

If you check these lab results against those obtained for some open-reel tape decks at 7 1/2 i.p.s., you will find they are very close or perhaps better!

Whatever electronic magic B.I.C. has bestowed on its new model to produce such results at 3 3/4 i.p.s. must have rubbed off on the slower speed, since even at the standard 17/8 i.p.s. speed, the T-3 performs beautifully -- again, response extends to beyond 20 kHz, wow and flutter are very low at.045 percent; distortion tops off at 1.3 percent; signal-to-noise varies from 57 dB to 65 dB, depending on what tape is used and whether or not the Dolby circuit is activated. But even the "worst case" figures here are on a par with what has been up to now regarded as high average performance for cassette decks in the over- $500 class.