Analog tape delay - better than digital echo?
Any enclosed space will create natural reverberation, where sound bounces off surfaces causing a million reflections, and an infinite number of reflections of reflections.
In the open air, a hard flat surface, such as a wall, the side of a building or a cliff-face, will cause a single echo. These phenomena are well-known and understood by both our conscious and unconscious mind.
Since natural echo and reverberation are a common feature of our aural experience, it is inevitable that they will be incorporated into our recording techniques. For some reason, these days we call echo 'delay'. 'Echo' is occasionally, and confusingly, used to mean reverb.
The simplest device that was commonly used in the past to generate delay, was the trusty Revox B77 (and formerly the A77) analog tape recorder. Because this is a three head machine, there is a gap - and therefore a delay - between the record and the playback heads. The set up is thus:
- Send signal from the channel to which you want to apply delay via a post-fade auxiliary send to the Revox.
- Switch the Revox to monitor off-tape.
- Bring back the output of the Revox to another channel.
Like magic, you now have a single echo on the signal which you can vary in level using either the auxiliary send or the fader of the channel to which the Revox is connected. The latter would be preferable since the noise level can be optimized.
The problem with this is that there isn't a great deal of control over the timing of the delay. At a faster tape speed, the delay time will be shorter. The varispeed control will also allow a small variation in timing.
However, before the days of digital delay, people would go to considerable lengths, and it was actually possible to construct an external varispeed control that would allow almost any delay time that could be musically desirable.
At longer delay times, the tape speed would be slower and therefore the quality of the delay signal would be poor, but that was considered to be part of the charm of the technique.
Even now, analog tape delay sounds subjectively better than digital delay. Although there are plug-ins that claim to recreate the sound of various types of analog tape delay, somehow they get the 'substance', but they don't quite get the 'magic'.
Perhaps that's why delay isn't used as commonly now as it once was...