External Sidechain Applications - BBE MAXCOM Owner's Manual

SPECIAL APPLICATIONS
The MAXCOM in a two way system

EXTERNAL SIDECHAIN APPLICATIONS

• THE SIDECHAIN CONNECTOR
The MAXCOM offers an exceptionally versatile external facility by using the SIDECHAIN connector. By using
this external control input, the MAXCOM control path is disconnected from the audio input and therefore inter-
rupted (see "BLOCK DIAGRAM"). The audio input is routed to the SIDECHAIN output (ring of the SIDECHAIN
connector) and the SIDECHAIN input (tip of the SIDECHAIN connector) it will now receive the new control signal
which is derived from an inserted effects processor.
If you want to use the SIDECHAIN connector as a control input just insert a simple mono jack plug. If you intend
to use it as a combined input and output (insert), it is necessary to utilize a special "insert cable" that splits up
one stereo jack plug into two mono jack plugs and is available in most music stores. The stereo end is used for
the SIDECHAIN connector while the two mono jack plugs will be connected to an equalizer, for example. Please
make sure that your connections are correctly made. The SIDECHAIN output will be connected to the input of
the equalizer and the SIDECHAIN input is routed to the output of the equalizer.
• THE MAXCOM AS A "DE-ESSER"
"De-essing" is a special application of frequency selective compression. A problem often encountered in record-
ing is the sibilant ("Ssss") sound of the human voice. High frequency sibilant sounds and pops can produce
very high energy levels which can sometimes cause an otherwise normal and undistorted voice to sound very
harsh, shrill and sometimes unintelligible. The solution is frequency conscious compression or limiting. The unit
responds only to selected frequencies and reduces the level temporarily, as soon as sibilant sounds or pops are
detected. If the detector circuit registers an excessive amount of high frequency information within the program
material, as in a normal compressor, the VCA is activated and the overall level is reduced. As this type of com-
pression affects the whole frequency range, this process is called broadband de-essing. Please note that this
type of frequency selective compression is very different from simple, fixed equalization using notch filters, since
de-essing has no effect on the signal except at the instant the sibilant occurs. The general frequency response
is principally not affected during this process.
When de-essing, simply insert an equalizer not into the audio path but into the sidechain path of the MAXCOM.
The equalizer is inserted between the SIDECHAIN output and the SIDECHAIN input of the MAXCOM and its
center frequencies are adjusted exactly to match the frequencies of the sibilant sounds. All other frequencies
are filtered out, so that with maximum attenuation of these frequency bands, along with a correctly adjusted
threshold point, the unit responds solely to the selected signal being produced by the equalizer. The level of the
sibilant sounds can therefore be effectively limited.
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