Orban OPTIMOD 5750 Operating Manual page 49

3-6
Operation
10-Tone Lissajous Pattern, 10-Tone Lissajous Pattern,
250-9250 Hz, 90 degree phase difference Processed by Phase Corrector
Because the process can subtly alter the stereo spatial effect, it may be inappropriate of "audiophile" formats,
although its advantages in reducing multipath distortion are likely to be far more subjectively important. It can be
smoothly activated and defeated via a delay-matched crossfade, so it is practical to do live switching between a
preset with the process active and one where it is inactive.
Because it adds about 250 ms of delay, the phase skew corrector can be bypassed completely in Setup. If you are
not using it and do not need to activate it smoothly "on-air," bypass it.
Figure 3-1 shows a 10-tone test stereo waveform with a 90 degree phase difference between each tone in the left
and right channels. Power (RMS) in the two channels is the same. Frequencies range from 250 to 9250 Hz in 1 kHz
increments. The 90- degree phase shift produces a different differential time delay for each tone: Each time the
frequency is halved, the delay doubles. Figure 3-2 shows the effect of the phase correction: all 10 tones are now in-
phase.
Two-Band Gated AGC: The AGC is a two-band device, using Orban's patented "master/ bass" band coupling. It has
an additional important feature: target-zone gating. If the input program material's level falls within a user-settable
window (typically 3 dB), then the release time slows to a user-determined level. It can be slow enough (0.5
dB/second) to effectively freeze the operation of the AGC. This prevents the AGC from applying additional, audible
gain control to material that is already well controlled. It also lets you run the AGC with fast release times without
adding excessive density to material that is already dense.
The AGC contains a compression ratio control that allows you to vary to ratio between 2:1 and essentially :1. Lower
ratios can make gain riding subtler on critical formats like classical and jazz.
The AGC has its own silence-gating detector whose threshold can be set independently of the silence gating applied
to the multiband compressor.
Equalization: The 5750 has steep-slope bass shelving equalizer and three bands of fully parametric bell-shaped EQ.
You can set the slope of the bass shelving EQ to 6, 12, or 18 dB/octave and adjust the shelving frequency.