High Band Rotary Control (12 Band) - TRACE ELLIOT AH1000-12 Guide D'utilisation

(16) HIGH BAND rotary control (12 Band)

This adjusts the amount of compression applied to the high frequencies in the signal; the further
clockwise the control is set, the more the dynamic range of the high end will be squeezed.
The compressor section of the 12 Band series uses two separate studio quality, dedicated dynamics
controller integrated circuits, and has been specifically designed for bass guitar due to the common
problems often experienced when using a normal, single band, compressor in this application.
With a standard compressor, the transition from non-compressed to compressed, i.e. crossing the
threshold, can often be abrupt and unnatural sounding, especially at high ratio settings. Also the
normal pre-set attack and release times always have to be a compromise between having it work
fast enough to catch rapidly changing signal levels (i.e. transients such as slapping techniques) or
too fast which can cause low frequency distortion.
To tackle these issues, the compressor on the 12 Band range has been designed as a dual band, soft-
knee compressor, with different attack and release times pre-set for each of the high or low bands,
and separate controls for the user to set the amount of compression applied to each band.
Dual band means that the signal is split into the high and low frequencies, each of which then goes
through separate compression circuits before being reconstructed.
The amount of compression of each band can be set by adjusting the LOW BAND and HIGH
BAND controls. This is similar to the sophisticated type of compression that is used for mastering
whole tracks to prevent unwanted pumping and breathing effects.
Soft-knee means that, above the threshold, compression is applied gradually, with the ratio
increasing as the input level goes up. The result is a smoother sounding compression than the
normal hard-knee type.
Different attack and release times are pre-set for each band so that the low band works slow enough
to prevent distortion at low frequencies and the high band works fast enough to catch transients.
The simple single control for each band makes setting the desired amount of compression easy as it
is effectively controlling the threshold, ratio and make-up gain simultaneously.
This is considerably less complicated than setting up a studio compressor from scratch as most of
the hard work has been done by our engineers and incorporated into the circuitry.
The circuit has been tuned so there should be little nominal signal level difference when switching
the COMPRESSOR on and off, however, this is dependent on the correct setting of the INPUT
GAIN control. If you find that the level increases too much when switching the COMPRESSOR on
then slightly turn up the INPUT GAIN. The opposite applies if the compressed sound is too low.
In this application a dual band compressor has several uses. If used solely for controlling the
dynamic range, it enables the bass player to switch between various playing styles, such as finger
style, slapping or plectrum. The circuit will compress as directed without distortion to the bottom
end, or transients taking hold of the whole signal level and causing pumping, which is very
obtrusive on bass guitar.
Applying compression to just the low band will fatten up the bottom end without losing the attack
characteristics. It is a less processed sound than full range compression and works well in
controlling the low frequencies, allowing higher volumes without stressing power amps or speakers.
It can also help to add definition to notes within a run without loss of the attack dynamics.
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