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User’s Guide
17
Stereo and Mono Sidechain Compressors for Tracktion
The Contour Edit Screen
This interactive graph does not show the ac-
tual input or output signals dancing across the
screen. It shows the contour we can apply to
the compressor to make it work as we want it
to. It's a bit like a Jello mold, it's shape affects
the shape of the Jello.
The input signal level in dB is the horizontal
axis, and the output level is the vertical axis,
with 0 dBfs at the top, and –48 dBfs at the bot-
tom (dBfs = dB full scale).
If the compressor did nothing to your signal,
then the contour curve would just be a straight
diagonal line, going from bottom left to top right
(input=output).
The example above shows a simple set up, with
just the Threshold (T) and End Point (E) in
place. Further nodes can be added between the
threshold and end point, to really make things
fl y. See the Node Editing section on page 19.
INPUT LEVEL dB
OUTPUT LEVEL dB
-48 -42 -36 -30 -24 -18 -12 -6 0
-48
-42
-36
-30
-24
-18
-12
-6
0
Threshold
The level at which the compressor starts work-
ing is called the threshold. The compressor will
reduce the level of signals above the threshold
volume level and not affect lower-level signals.
You can adjust the threshold by grabbing the T
node on the graph, or by adjusting the slider.
The threshold has been set here to –30 dB, so
any input levels lower than –30 dB are not af-
fected by the compressor. For example, an input
signal of –42 dB has an output of –42 dB, (as-
suming no Makeup gain has been added).
End Point
You can adjust the End Point by grabbing the E
node on the graph, or by adjusting the slider.
The End Point shown here, is set to an output
level of –18 dB.
Any input signals higher than the threshold will
be attenuated by an amount determined by the
slope of the graph. For example, if the input
level is –12 dB, follow the –12 dB line vertically
until it hits the line joining the T and E nodes.
From there, follow horizontally to the left, and
read the output level (approx –23 dB).
As a test, sit up straight, get a 2B pencil and fi ll
in the output levels for the following input lev-
els, from the graph:
Input Level dB Output Level dB
0
–6
–12 –23
–18
OK, sorry about the test there.