Audio Visual Cassette Deck
The compact cassette format was originally introduced for use in dictating machines, and it never fails to amaze me just how far this basically unpromising system has advanced in terms of sound quality. I even lowered myself to buy a cassette deck last year, after being a committed reel-to-reel supporter for ages, but that's another story. On the face of it, the machine reviewed here is just another cassette deck, but it has some interesting and unusual features which warrant its inclusion in the pages of this magazine.
The biggest departure from the conventional format is the use of half track recording. This is nothing to do with pointing microphones at a military vehicle, but a different way of using the tape in the cassette. Normal stereo cassettes split the width of the tape into four equal tracks, two of which are recorded in one direction, and two in the other direction when the cassette is turned over. In a mono machine, the heads are double width, and two tracks are recorded or replayed simultaneously. Since there is only one tape speed, 1⅞ inches per second, a tape recorded on any cassette machine will theoretically play back on any other machine, even if only in mono in some circumstances. This is in direct contrast to reel-to-reel recording, where there are six speeds in general use, and seven different track formats on ¼" tape alone, many of them totally incompatible with each other.
The reason is basically this: higher tape speed gives improved frequency response, a better signal to noise ratio and less drop-outs (where the tape momentarily loses contact with the heads; if you've listened to an indifferent cassette on headphones you'll know about these). Wider tracks on the tape also give less noise and less drop-outs. Manufacturers of hi-fi cassette decks have recently cottoned on to these principles, and there are now a few recorders which go at twice normal speed, such as Teac's C-3X and the famous Portastudio.
The primary function of the 124AV is in audio-visual presentations (slide shows to you), where one of the tracks has pulses recorded on it which tell the projector when to change slides. Obviously, if one of these pulses were missed, the slides would be out of synchronisation with the music or commentary from that point on, and freedom from drop-outs is of primary importance. To help in this area, Tascam have opted for the half track system, where the tape is split into two tracks recorded in one direction only. Since you can no longer turn the cassette over, they have retained the standard slow speed to help avoid the need to change cassettes in the middle of a session.
This does mean that cassettes recorded on the 124 cannot be played back on a normal machine (you would only hear one channel); and conversely, a normal cassette played back on the 124 would give you side 1 in mono on the left channel, and side 2 backwards on the right channel, again in mono. Not a lot of use! In view of the things this deck can do for you, I think its appeal would be much wider if it could also be used as a normal cassette deck. It certainly looks like one, and not enough noise is made about the unconventional tape format in the otherwise excellent multi-lingual instruction book. There is nothing at all on the machine itself; the Portastudio comes with a label stuck to its cassette door warning users about incompatibility. This is meant to be professional equipment, I accept, but instruction books have a habit of being either lost or not thoroughly read; a user in a busy audio visual department who was not 'in the know' could get confused quite quickly.
The second major feature, and the one most likely to be useful to musicians, is the simul-sync facility. This enables you to play back one channel — the left — and simultaneously record on the right hand channel only, something you can't do on an ordinary stereo deck. For a start, the erase head is usually mono, and so it would rub out both channels even if the record/replay switching were altered.
In audio-visual applications, this allows music and commentary to be recorded on the left hand channel, and synchronisation pulses can be recorded at a later date whilst listening to the soundtrack. The 'cue-select' button allows the 124 to be compatible with virtually all commercial programming equipment, even the newest digital units.
With the cue-select button in position 1, audio signals may be over-dubbed just as easily as programming pulses; for the musician this means that an instrument may be recorded on the left hand channel, followed by another instrument or vocal on the right hand channel. This may be rather unsophisticated compared to a Fostex 8-track for instance, but it's ideal for working out song arrangements and similar work. The deck is very straightforward to use, aided by another useful feature, the 'memory' button. If the tape counter is reset at the beginning of a piece, and this button is engaged, the tape will stop (from rewind only) whenever the counter reads 000. You can easily rewind and start from the beginning as many times as necessary to get something right; I wish my Teac A3340 had one of these!
One departure from normal simul-sync schemes is that you can only overdub on the right hand channel; should you suddenly decide that your original recording was wrong, you can’t redo the left hand channel by itself. Instead, you have to erase everything and start again. This is no hardship for 'roughing out' an arrangement, and after all, you aren’t going to record your next LP on the 124AV.
Another facility is 'mic blend' which allows you to mix in a single microphone in mono whilst recording stereo music. This facility also works during playback, so you can add live commentary to a pre-recorded soundtrack without needing an extra mixer; or if you've recorded two instruments using simul-sync, you could re-record them on a second deck and add vocals (for instance) at the same time.
The rest of the unit is fairly standard, with switches for bias and equalisation setting (chrome and normal only, no metal position) and Dolby B noise reduction. The VU meters are easy to read, and illuminated; there is also a light behind the cassette window, so you can work the equipment in the dark, the favoured environment for slide presentations.
To sum up, everything works smoothly without obvious nasties, and the unit is well built (if a little empty inside). The half track format means the unit is unlikely to sell in vast quantities to domestic customers, but should be useful to audio visual departments, musicians and in education.
Recommended retail price of the 124AV is £195, including VAT.
Tascam products are distributed in the U.K. by Harman (Audio) U.K. Ltd, (Contact Details).