User manual RANE G4

[. . . ] Listen to the key signal and adjust the LOW-CUT and HIGH-CUT filters to respond only to frequencies of interest. Watch the SIDE-CHAIN meter and adjust the THRESHOLD until the yellow TH indicator lights at the desired level. Basic Expander: Expander operation is similar to that of the Gate, with two important control differences: · The HOLD control is not active in EXPand mode. Listen to the key signal and adjust the LOW-CUT and HIGH-CUT filters to respond only to frequencies of interest. [. . . ] The HOLD time is reasserted whenever the peak signal moves above the Gate or Duck threshold. Depth / Ratio 60 80 dB LOW-CUT HIGH-CUT 40 20 0 2 1 4 6 8 n:1 DEPTH RATIO In Gate mode, the DEPTH control determines how many dB the signal is attenuated when the key input is at or below threshold. In Duck mode, the DEPTH control determines how many dB the signal is attenuated (ducked) when the key input is at or above threshold. In Expand mode, the RATIO control indicates the ratio of output change to input change when the key signal is at or below threshold. For example, with a ratio of 4:1, the output level decreases 4 dB for every 1 dB the key signal moves below threshold. The DEPTH control has no effect in Expand mode. The side-chain, 12 dB/octave Butterworth LOW-CUT and HIGH-CUT filters are used to limit the detector's response to a particular range of frequencies, thereby minimizing false triggering. They do not affect the main output (unless you accidentally leave the LISTEN switch engaged). Side-chain filtering is advantageous in virtually all dynamics control applications. For example: · Adjust the HIGH-CUT filter to tune out the mic bleed from the snare drum or cymbals when gating a kick drum or tom mic. Similarly, adjust the LOW-CUT filter to tune out the kick drum when gating a snare mic. · Adjust the LOW-CUT filter to eliminate background noise (a low frequency air conditioner, for example) when using a speech microphone to duck music. The filtered signal is less likely to false trigger, while the detector remains sensitive to voice signals. Manual- Operation The G4 has 3 modes: Gate, Ducker or downward Expander. Side-chain Detector The side-chain detector compares a reference signal, commonly referred to as the key signal, to the Threshold in order to determine the response of the Gate/Ducker/Expander. This reference signal may be a version of the main input (Internal side-chain) or another signal altogether (using the External sidechain inputs). Two types of detection are used in the G4: · Peak detection is used in Gate and Duck modes to accurately capture and reproduce transients. · True rms detection with a fixed 35 ms averaging time constant is used in Expand mode. The look ahead detector works as follows: the main signal is delayed, while the side-chain signal is not delayed. This delay is extremely short (a few millionths of a second) and can't be heard. The G4 examines the signal in advance and determine the appropriate response before an event (see Figures 2 and 3). This action allows the Gate and Ducker to turn on before a transient occurs. Pre-ramping the signal allows the main signal to be gated-on as the signal reaches the threshold. Look ahead pre-ramping serves two purposes: · Leading edge wave shape is preserved above 1 kHz (see Figure 2). [. . . ] Look ahead without ramping often causes an audible click at fast attack and moderate to extreme depth settings. Only look ahead pre-ramping ­ as done in the G4 ­ accurately reproduces the 1st cycle of a kick drum without adding excessive delay or significantly altering the leading edge. 1 V 100m E SID -40 -CH -35 AIN INP UT DUCKED SIGNAL 10m -30 -25 -20 -15 -10 INPUT dBu -5 0 +5 +10 +15 +20 1m The above graph shows the operation of the Ducker. The signal is attenuated when the side-chain key input goes above threshold. In the above example, the dashed-line green trace shows the signal being ducked. [. . . ]