Behringer MULTIGATE PRO XR4400 Manual - Page 11

11 MULTIGATE PRO XR4400 User Manual output threshold gain 0 dB 5.4 The SIDECHAIN filter Each channel has a parametric filter whose frequency and quality (bandwidth) can be set precisely. This tunable filter allows you to select and fade out specific frequencies that would otherwise lead to unwanted triggering of the expander circuit. IRC curve expander. 1:8 noise gate, 1:∞ 5.4.1 The MONITOR function This switch links the sidechain control signal with the audio output, while muting the audio input signal, so that you can pre-monitor the filter output and tune the parametric filter. ◊ Please note that the channel's entire processing functions will be disabled when you press the MONITOR switch. input Fig. 6.3: IRC characteristic curve The result is an expansion process that is less difficult to adjust and more tolerant towards wanted signals whose levels are only slightly above the level of the background noise. 5.2.6 RATIO function The ratio of the input-level-change vs. output-level-change after the onset of the control process, i.e. after the signal has dropped below the threshold, is called expansion ratio and can be set with the RATIO control. RATIO settings from 1:1.2 through 1:4 give you smooth and exactly dosed downward expansion. The RATIO scale printed on the front panel indicates the expansion ratio in decibels, i.e. it shows you the decibels by which the output signal is cut for each reduction by one dB of the input signal. With a 1:1 ratio the output signal level is the same as the input signal level, i.e. there is no signal change. A ratio of 1:2 means that the output signal is reduced by 2 dB when the input signal drops below the threshold by 1 dB. Accordingly, with a ratio of 1:4, the output signal is cut in level by 4 dB when the input signal is 1 dB below the threshold. 5.3 FLEXLINK function The four channels of the MULTIGATE PRO can be operated both independently of each other and in couple mode. In particular, when you record a choir it will be useful to couple the individual microphone channels. For example, when all microphones are controlled by one singer, all vocals start and stop precisely at the same point of time. Also when synchronizing several instruments, inaccurate entries of individual musicians can be avoided. To expand phase-coherent stereo signals (i.e. signals having the same phase), it is imperative that the control processes be triggered simultaneously in both channels. Due to the differences in perceived loudness between the left and right channels, unwanted shifts with reference to the stereo basis would be produced. The innovative FlexLink function implemented in the MULTIGATE PRO allows for a variety of couple options. For example, when you press the COUPLE switch of channel 3, this channel is automatically configured as a "slave" channel, while its neighbor-channel 2-becomes the "master" now controlling both channels in all their parameters. Activating the COUPLE switch automatically disables all controls and switches of channel 3 (except for the MONITOR switch). Now, the controls of channel 2 take over full control of channel 3. Similar to a stereo fader, both channels work in sync. To control channels 2 and 3 from channel 1, simply press the COUPLE switches of channel 2 and 3. 6. Applications This chapter describes a few typical applications of the BEHRINGER MULTIGATE PRO. Starting from the basic setting shown below you can find solutions to most dynamics-based problems. Please take your time to study the following application examples thoroughly, so as to be able to fully exploit the variety of features your MULTIGATE PRO offers. Basically, the BEHRINGER MULTIGATE PRO can be used in three areas of application: 1. Eliminating interference noise and suppressing crosstalk in multi-channel or multi-microphone configurations. 2. Expanding the dynamic range of compressed program material, refreshing sampled sounds and creating special effects and sounds. 3. Using the MULTIGATE PRO as a de-esser and to specifically eliminate interference noise from recordings as well as to reduce the risk of feedback in live situations. 6.1 Basic setting Understandably, there is no standard setting that suits all kinds of applications. Rather, the controls and switches must be set specifically for the application on hand. However, by studying the following practice-oriented descriptions of typical applications you will soon develop a feel for how the various functions work: 6.1.1 The gate function "Gating" is a so-called "high ratio" expander function and represents the simplest function of the BEHRINGER MULTIGATE PRO. When the expander is operated with maximum gain reduction (RANGE control fully to the left), it works in "hard gating" mode. The gate function is used to automatically mute single channels in multitrack mixdowns, stage microphones currently not in use and to suppress background noise and crosstalk in multi-track recordings. In particular, when processing percussive instrument the use of the "hard gating" function is recommended. A few examples show you how to do it: Electric signals from percussion instruments have a very short rise time. The time between single hits on the instruments is normally filled up with noise produced by adjacent instruments or room reverb, which makes it difficult or even impossible to separate microphones acoustically. This unwanted crosstalk effect can be accurately eliminated with the MULTIGATE PRO.