Behringer XR4400 - Manual (Page 15)

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MULTIGATE PRO XR4400
5.2.2 Attack, release and hold times
The BEHRINGER MULTIGATE PRO is equipped with a MODE switch as well as a HOLD and RELEASE
control to adjust the time-domain parameters that determine the so-called envelope:
Fig. 6.2: Principle of envelope function
Attack time
The quality of an expander/gate is largely determined by the speed of its attack function (rise time). This
parameter defines the time the expander needs after the signal has passed the threshold to recover from the
applied gain reduction, i.e. to reverse the control process.
Extremely short transients (level peaks) such as hand claps and percussive instruments, etc. require an
extremely short attack time to prevent the expander from cutting the signal flanks and thus deteriorating the
sound.
The new BEHRINGER-developed UTR circuit (Ultra Transient Response) in combination with a high-grade VCA
allows for an extremely short response time in gate mode, without audible switching noise as it is generated by
many conventional designs.
Release time
Another important parameter is the release time, as it determines the time the gate needs to reduce the signal
level by a certain amount, after the signal has dropped below the threshold.
Hold time
The hold-time parameter enables you to delay the starting point of the release process. In particular, when
processing frequently interrupted signals such as vocals, an additional hold-time parameter is indispensable to
prevent the gate from switching off and back on during signal pauses.
5.2.3 IAC circuit (Interactive Attack Control)
The MULTIGATE PRO features an IAC circuit (Interactive Attack Control) which analyzes the program material
to calculate the attack time by way of interaction, so that the hold/release process is triggered automatically
depending on the program material. This is the reason why the MULTIGATE PRO does not need a dedicated
attack control.
5.2.4 RANGE function
On the MULTIGATE PRO the dynamic processing is controlled by a high-grade VCA with a working range of
more than 100 dB, i.e. the input signal can be reduced in level by as much as 100 dB.
For most applications, however, it is neither desirable nor necessary to cut the signal completely after it has
dropped below the threshold. In particular, when processing signals with lots of background noise, this would
result in abrupt and audible control processes that are less likely to enhance the overall sound quality.
For this reason, the MULTIGATE PRO is equipped with a RANGE control that allows you to limit the maximum
5. TECHNICAL BACKGROUND