Suppression Of Crosstalk In Multi-Channel Operation; Basic Settings Of The Gate Section - Behringer ULTRA-DYNE PRO DSP9024 User Manual

The Peak Width parameter is dependent upon the delay parameter in the <GLOBAL SETUP>
menu. The Peak Width Gate parameter will have no effect if the delay has been set to 0 ms. In
addition, the delay time set in the <GLOBAL SETUP> menu should be twice as long as the
desired Peak Width time of the Gate.
Using the Peak Width parameter permits the ULTRA-DYNE PRO to identify and ignore brief signal peaks on
the basis of their duration. For this reason, select a suitable setting for this parameter corresponding to the
maximum duration of the signal peaks to be ignored. The peak width parameter also ensures that an open
gate does not close for signals shorter than the set duration.

3.2.1 Suppression of crosstalk in multi-channel operation

One of the most common applications for an expander/gate is the suppression of undesirable crosstalk between
individual channels during recording and playback. This application is used very frequently when recording acoustic
percussion instruments due to the close proximity of the microphones to one another. The high sound pressure
levels of the individual instruments causes crosstalk in all of the neighboring microphones, leading not only to
frequency cancellations but also to a lack of definition in the sound (comb filter effect). The optimal solution is
thus to use a separate microphone for each instrument, with individual gating for each microphone.
Insert the BEHRINGER ULTRA-DYNE PRO in the recording channel in of the snare, for example, and set the
unit to respond to signals from the snare only. Each microphone should be carefully positioned and checked
beforehand, and the Threshold value set to ensure a clean acoustic separation of the drum sound, as if the
instrument were being played alone.
Correct miking technique is decisive for the optimal function of the Expander/Gate. Be especially careful when
instruments with pronounced high frequencies are being played next to or behind a cardioid microphone.
The directional characteristic of most microphones is considerably less effective at high frequencies. A
difference of only 2 to 3 dB in the response sensitivity between the main and lateral axes in the 5 to 10 kHz
range can result in severe cymbal crosstalk in the tom microphones, or masking of the snare by the hi-hat.
Take maximum advantage of the directional characteristics of the respective microphones to ensure the best
possible acoustic isolation of the instruments.
Be sure to do everything possible to isolate the individual sources with proper miking technique alone.
Otherwise, the Expander/Gate will not be able to provide a clear acoustic separation.

3.2.2 Basic settings of the Gate section

Begin with very low Threshold values so that the entire signal can pass unhindered. Next, move the fader
upwards until all background noise has been removed and only the desired instrument is still audible.
The hold time can be adjusted to optimize the unit for the program material. It may contain many, frequently
short, pauses which can result in the Gate being activated repeatedly in short succession. The Hold function
prevents the disturbing "flutter" common to conventional gates by delaying the release process. This ensures
that the Gate remains open during short pauses. The Gate closes the audio channel in the preset release time
after the hold time has elapsed.
The release time may also be used to adapt the Gate perfectly to the program material. As a rule, percussive
audio material with little or no reverb is processed with quick release times, whereas longer release times are
used for signals with a slow decay or heavy reverb. You will note that short release times are suitable for most
percussion instruments, while longer times are generally required for toms and cymbals.
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ULTRA-DYNE PRO DSP9024
Parameter
Threshold
Hold Time
Release Time
Peak W idth
Tab. 3.1 Basic settings of the Gate section
3. APPLICATIONS
Setting
-90 dB
20 ms
20 ms
0 ms