of Microprocessors

MUSIC SYNTHESIS SOFTWARE 703
interpolation between points. Although the voice waveforms are only 8 bits
before the amplitude envelope is applied, all later processing is carried to 16
bits of accuracy. This compromise greatly speeds up multiplication, which is
a software subroutine on the 6502, and is nearly impossible to hear when
several instruments are playing. Tre same Bach score transcribed 10 years
earlier was run through the system and required about 5 hours of processing
time for the 8 min piece; about a 40-to-l ratio. In addition to NOTRAN,
there is a playback program, a record program (A-to-D conversion into a
sound file), a reverberation program, and several miscellaneous utilities.
For the immediate future, NOTRAN, of course, will be recoded into
68000 assembly language, which should provide about a 6-to-l speedup
along with greater precision (lK waveform tables with 16-bit samples). A pair
of removable media 10M byte disk drives is also being added, which should
allow stereo operation at 30-40 ks/s and several minutes per disk. Since the
68000 promises to be a popular microprocessor for music synthesis and can
run high-level languages such as C reasonably efficiently, it should also be
possible to run some of the other delayed-playback synthesis programs being
developed at universities. The CARL system, which will be described in the
next chapter, seems to have the most potential in this respect.