Orban OPTIMOD-FM 8600Si, Operating Manual

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3-102
OPERATION ORBAN MODEL 8600Si
Distortion Control : In 1977, Orban was the first company to patent 3 and commer-
cialize a psychoacoustic model to estimate and control audible clipping distortion.
The 8600 also uses a psychoacoustic model, but in a far more sophisticated way that
has some similarities to audio codec technology.
Figure 3-6 on page 3-100 is a twelfth-octave ratio that compares the spectrum of the
8500 and 8600 outputs in a more detailed way than the third-octave ratio seen in
Figure 3-5. It shows the 8600’s 4.6 dB suppression of (mainly harmonic) clipping dis-
tortion centered at 3.668 kHz caused by sustained electric guitar riding on top of
bass.
Figure 3-7 on page 3-101 shows a piece of material that has been used by others to
demonstrate distortion control. This material consists of Clarkson’s humming over a
3
US patents 4,208,548 & 4,241,266, used in Optimod-AM 9000A
Figure 3-8
Level 42, “Starchild”