Thoughts on the Schober Rezounder

I have been looking at the design of the Rezounder, Schober's replacement for the Reverbatape, and it strikes me that they made an economic error in it's design.

Effectively, they copied of the design of the Reverbatape, when they would have been better taking a slightly different approach.

First the reverbatape:
The reverbatape records the signal to the tape, then retrieves it three times, with three separate heads spaced approx. 100ms apart. It then loops the signal from the last head back into the record head.

Why use three heads? The answer to this is sound quality. Each time a signal is recorded to tape, then played back again, it degrades. By playing back each recording three times, at delayed intervals, the number of record/playback cycles is effectively reduced by three - the playback from the second and third heads will be the same quality as that of the first. Likewise, echoes 4,5 and 6 all of which result from the signals second time though the system, are again of the same quality as each other, and only two generations old. A comparable echo done on a single head playback system would be 6 generations old, with three times as much quality loss by the last of the six echoes.

The Rezounder followed pretty much the design concept of the Reverbatape, though instead of using the distance between tape heads to introduce the delay, it uses a trio of BBD delay chips, each of which was frightfully expensive at the time.

The signal passes through each of these three delays in turn, then after the third delay is looped back into the input for delays 4,5, and 6, much like in the reverbatape. Each successive delay output (echo) is dropped by a further 1db when added to the output mix.

The sad thing here is that there is no advantage whatsoever in using three of these delay chips in series. Unlike the reverbatape, where there is only one record action for three playback actions, each delay chip in essence records and plays back within itself (not quite how it does it, but adequate for this concept), and thus subjects the signal to a loss of quality, so after passing through the three chips the first time, the signal has been degraded three times.

The exact same effect, with the exact same quality loss would result if a single delay chip was used, with a 1db reduced signal being fed back into itself, thus reducing the number of chips to 1/3. This I suspect, would have come near to halving the cost of the kit.


Article, art & design copyright 1999-2003 by Ken Stone

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