Upper line shows Low-level compression (upward), achieved when Range is negative and Gain is equal but positive. Lower line shows Low-level expansion (downward), achieved when Range is positive and Gain is equal but negative. Graph is taken from C1 to help visualize the gain structures in the LinMB.
LOW-LEVEL EXPANSION (NOISE GATE)
If you are interested in a noise gate for a particular band or bands, set Range to a positive Value, Gain to the inverse of the Range, and Threshold to a low value (say -60dB). Similar to the above example, at high levels the full dynamic gain increase set by the Range is retained, and is fully compensated for by the Gain. While around and below the Threshold, the dynamically changing gain comes closer to 0dB, and the result is that the fixed negative Gain is applied to the low level signal — which is also known as gating (or downward expansion).
“UPSIDE DOWN” THINKING
These low-level examples may seem a little inverted to what you would expect. For instance, that a noise gate would have a positive Range.
If you just remember that when the signal goes around the Threshold, then the Range becomes “active”, and that the Threshold is the halfway point of the Range. So whether Range is +12dB or –12dB, then audio 6dB above and 6dB below the Threshold is where the “knees” of the dynamic change will occur.
Positive Range
Then, if Range is positive and Gain is set to be the negative of Range (opposite but equal), then around and above the Threshold all audio will be a 0dB gain (unity). Below the Threshold, the Range is not active, so the Gain (which is negative) “takes over” and reduces that band’s gain. This is what gives the downward expansion.
Negative Range
Another seeming example of the “upside down” concept is that low-level compression takes a negative Range. Again, remember that in the LINMB, whenever the audio is around the Threshold, the Range is active. So, if we set Range to negative, anything around or above the Threshold can be reduced in gain. However! Here’s the tricky part: if we set Gain to perfectly offset the Range value, then everything well above the Threshold has no effective gain
Waves LinMB software guide page 17 of 28
