This is a patch which works as a 3-band stereo compressor with noise gates. The patch can be used to give a nice face-lift to your master mix.

To begin with there is a Left and a Right filter section. Here you set the three band ranges for each channel. Each band is then routed to a Stereo Compressor and Stereo Expander section (the Expanders work as noise gates). The three different stereo bands are then mixed and routed to a master" Stereo Compressor (works only as Limiter here).

By switching between 1 and 2 on the two BYPASS switches, you can compare the processed and bypassed signal of each stereo channel. '1' is processed and '2' is bypassed signal. As you adjust the parameters in the patch, it's a good idea to frequently switch and compare processed and bypassed signals until you have reached the desired right-in-your-face sound.

Some hints: Adjust the Threshold values of the Expander modules to eliminate any input noise. Try adding, for example, two (one for each channel) Overdrive modules after the EXPANDER HI module to add more treble to the processed sound.

Have you ever used your Nord Modular or Micro Modular as an audio processor for external signals? To show an example of what you can do, we have created a patch which works as a 3-band stereo compressor with noise gates. This patch can be used to give a nice "face-lift" to your master mix.

To begin with there is a left and a right filter section. Here you set the three band ranges for each channel. Each band is then routed to a stereo COMPRESSOR and stereo EXPANDER section (the expanders work as noise gates). The three different stereo bands are then mixed and routed to a "master" stereo COMPRESSOR (works only as limiter here).

As you adjust the parameters in the patch, it's quite easy to compress the sound too much. Therefore, it's a good idea to frequently compare processed signals with unprocessed signals. By switching between '1' and '2' on the two BYPASS switches, you can compare the processed and unprocessed signal of each stereo channel. '1' is processed signal and '2' is unprocessed (bypassed) signal.

Using attack times faster than 1 msec or release times faster than 40 msec can cause problems with standard compressors. They can produce ripples leading to distortion of the compressed signal. An improvement can be made by giving the envelope-follower portion of the compressor lookahead capabilities. basically the same algorithm discussed above, with an additional network of ten "future peak-detectors". Each such a detector constantly "looks at the future", trying to locate new peaks which are about to arrive in the next la seconds (la is a predetermined parameter controlled by the user.) If the envelope is in a release stage and a "future" peak which is higher than the current envelope value is detected, the gliding envelope freezes until the expected peak arrives. This mechanism efficiently eliminates various types of distortion which otherwise would have been applied on the compressed sound. Instrument 3 contains the main envelope follower and the gain-reduction unit. It uses the future peak information collected by instrument 2 instances by accessing the global variables gklap0..gklap9. Owing to the look-ahead concept, the output signal is delayed in la seconds. It also means that the algorithm is not a pure "real-time" one. However, this envelope detector generally provides very smooth, reliable and fast-responding results.

Expanders are the opposite of compressors. They act to increase the amplitude of loud signals while attenuating soft signals. Their major purpose is to reduce the perceived level of noise in a signal. A noise gate is a very extreme form of expansion, where portions of the signal whose level is below a given threshold are set to zero, and all other portions are passed through unchanged. Lookahead capability can be very useful in an expander or noise gate, as the attack and decay times of these are typically quite short.

Some dynamics effects have a side-chain input in addition to the usual input. In this case the envelope follower is applied to the side-chain input, and the dynamics processing derived from this envelope follower is applied to the usual input. There are a number of uses of this effect. For example, one can make a "De-Esser", which attenuates sibilant sounds (such as some vocals) by passing the source signal through a bandpass or highpass filter and feeding the filtered signal to the sidechain input. The unfiltered input is passed directly to the normal input of a compressor. When the sibilance of the source is high, the amplitude of the source signal will be attenuated by the compressor.