of Microprocessors

44 MUSICAL ApPLICATIONS OF MICROPROCESSORS
A so-called "full-track" tape recorder is very helpful when extensively
editing tape. Such machines record on the full width of the tape; thus, it may
not be turned over for additional recording time. Although such machines
are hard to come by in the consumer new equipment market, they are fairly
common as professional equipment. Stereophonic effects are typically added
as a separate step later after the basic composition has been completed. Also
the higher tape speeds available are typically used. Besides better recording
fidelity, the many pieces of tape to be manipulated will be larger and easier
to handle.
Rearrangement
The most fundamental splicing modification is rearrangement of a
previously recorded sequence of sounds. Since a fair amount of experimentation
is usually required, the sequence is typically copied several times before
cutting commences. One interesting introductory experiment is ro record a
scale from a musical instrument and rearrange it to form a melody. Timing is
fairly easy to control since time = distance along the tape. Even 50 msec is
3/4 of an inch at 15 inches/sec.
More interesting results are obtained if parts of the envelopes of notes
are removed or attacks and decays are interchanged. In particular, using just
the attack portion of many musical instrument notes can create some very
interesting results that usually will not resemble the source instrument at all.
A related procedure that works well with full-track recorders is to make
an extended diagonal splice rather than the typical short diagonal or straight
splice. The result will be that one sound will seem to dissolve into another. If
a piece of tape is spliced in slightly crooked, the high frequencies will be lost
on playback and the result is as if a curtain had been pulled over the sound
source. The angle of the crooked piece determines the extent of highfrequency
loss with greater angles producing greater losses.
With full-track equipment, a piece of tape may also be spliced in
backward. At first that might not seem like a very powerful technique, but it
is. For example, ordinary English speech becomes a very strange, gutteral
sounding foreign language nearly impossible to repeat accurately. A very
interesting experiment is to record a sentence and learn to repeat its backward
sound. Then the sentence is spoken backward, recorded, and played
backward again. The resulting accent is unbelievable!
A piano recording played backward sounds like an organ with the ends
of notes "snuffed out" by a breath of air, This is one demonstration of the
importance of the amplitude envelope in determining the overall timbre of a
sound. A simple piano piece performed backward and then played backward
so the music is forward is another interesting experiment.
Even ignoring envelopes, which is the case with relatively steady
sounds) the character ofmany sounds is completely changed by playing them
backward. If a recording of a contralto or bass singer is played backward) the