Metric Halo Production Bundle - Manual (Page 46)

Processing
46
important part of ChannelStrip because it allows you to test different processing scenarios quickly and easily.
It also allows you to compare the two different approaches without having to stop the transport so you can
get a much more visceral comparison.
Theory Of Operation
The operation of the compressor is very similar to the gate. Based upon your setting for the sidechain routing
switch, either the sidechain input signal or the channel signal is fed to the sidechain filter. The sidechain filter
provides one band of equalization that may be used to accentuate or cut certain frequencies (parametric or
shelf filters) or limit the key to a certain range of frequencies (cut or bandpass filters). You control the filter type
and the filter parameters with the filter type button and the “dB”, “Hz” and “BW” knobs.
You can enable the sidechain filter with the enable button. After the sidechain signal has been processed by
the sidechain filter it is measured by a level detector that determines the instantaneous level of the signal (in
the case that ChannelStrip is running in stereo mode the detector is linked with the other channel in the stereo
pair and the higher level of the two channels is used).
When the compressor is enabled the signal will be attenuated based on how much the detected level is above
the threshold you set with the “Thresh” knob and what compression ratio is set with the “Ratio” knob.
The dynamic behavior of the opening and closing of the gate is controlled with the “Attack” and “Release”
knobs and the compressor character switch.
Audio Dynamics
Compressors are important in controlling the dynamic range of the source material you are working with.
While the instruments, your ears, the microphones and your digital audio workstation all have dynamic ranges
that are greater than 100 dB, most reproduction and delivery media have significantly reduced dynamic ranges.
Compression is used, in its simplest form, to help reduce the dynamic range of your project or elements of the
project to a range that is reproducible. It does this by making the soft material louder and the loud material
softer. This type of processing can also be used to change the character of the sound instead of just adjusting
the dynamic range. The compressor in ChannelStrip excels at both types of processing.
Compressor Enable
This button is in the Master Enables section. When this button is off, the compressor section will not change
the signal. The order of this button will change depending on whether the compressor is set to “Post EQ”.
Post EQ
The “Post EQ” button places the compressor section after the equalizer in the signal chain. By providing the
capability to switch the routing on the fly, ChannelStrip allows you to determine the most effective routing for
your particular signal quickly and easily.
Auto Gain
When the “Auto Gain” button is enabled the compressor automatically adjusts the makeup gain in the com-
pressor output stage so that if the manual “O Gain” knob is set to 0 dB the static gain reduction for a 0 dB
input level will be about 7 dB. This number was chosen because it works well with the default settings of the
“Attack” and “Release” knobs to provide enough pad to not clip fast transients. The “O Gain” knob will apply
additional trim to the internal automatic gain. If the threshold is set very low (e.g. –60 dB) and auto gain is
enabled, you will not be able to add very much manual gain (only about 1 – 2 dB) even though the readout
on the knob will go up to + 30 dB. This is an internal limitation of the compressor.
Compressor Knee Control
The “Knee” knob allows you to adjust shape of the compressor transfer function when the Compressor Char-
acter is set to MIO (the Knee control has no effect for the other compressor character algorithms and will not
be visible in those modes).