Compressor
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The Orinj Compressor automatically adjusts the amplitude of the incoming signal, usually to bring
together quieter and louder parts of the signal (compressing) or, more rarely, to further separate
quieter and louder parts of the signal (expanding). A compressor has many uses:
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Automatically bringing louder and quieter parts of the signal together can be used on vocals to
ensure that vocals do not overwhelm certain parts of the song while getting lost in other parts
of the song.
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Decreasing the amplitude of the ring of drum hits ensures that the initial drum hit is sharper.
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Quickly decreasing the amplitude of high frequencies in vocals automatically when these high
frequencies become notable can be used for de-essing – removing the "s" sounds from the vocals.
This particular compressor works on three different frequency bands separately. Bass frequencies
(below 300 Hz) are treated separately from mid-range frequencies (between 300 Hz and 1500 Hz) and
both of these frequency intervals are treated separately from high frequencies (over 1500 Hz). In
many uses of the compressor, this is not necessary. For de-essing, however, it is useful to be
able to separate and act only on high frequencies.
As a quick example of a compressor, consider a compressor with a threshold of -30 dB, a compression
ratio above -30 dB of 2:1, and a compression / expansion ratio of 1:1 below -30 dB. If the signal
has amplitude of -25 dB, it is above the threshold by 5 dB. This difference between the signal and
the threshold of 5 will be compressed with the ratio 2:1 to a difference of 2.5 dB. This means that
the output signal will be at -27.5 dB. If an input signal has the amplitude -35 dB, it is 5 dB
below the threshold. Since the compression / expansion ratio below the threshold is 1:1, this
signal will remain unchanged. Thus, this specific example compressor makes loud signals less loud
while leaving quiet signals the same.
Compressors have other parameters, such as attacks and releases. These are explained below. In
addition, there are two types of compressors – one that acts on the peak amplitude of the signal
(i.e., the actual value of the signal at a specific point in time) and one that acts on the
amplitude envelope of the signal (i.e., a measure of the power of the signal over an interval of
time, independent of what the peak value of the signal at the specific time is). This compressor
is of the second type.
Using the Orinj Compressor
The Orinj Compressor can be added to tracks in
the multitrack session view,
tracks in the
loop building view,
and to waves in the
single wave view. In the multitrack session view and
in the loop building view, first
select the track to which you want to add the effect. In all of these views, click on Effect,
Dynamics, and then on Orinj Compressor in the Orinj menu.
You will see the following dialog.

When this dialog becomes visible, the Orinj Compressor has been added. Adjust the compressor
parameters in the dialog – these parameters are described below – and click on Close.
Orinj Compressor parameters
See Effects for an explanation of the Title, Track, Presets, and
Bypass controls. The remaining Orinj Compressor controls are described below:
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Band tabs: Use the band tabs to switch between the frequency bands of the compressor –
"< 300 Hz", "300 Hz to 1500 Hz", and "> 1500 Hz".
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Graph: Use the graph to add compressor points. The graph shows how the compressor changes the
amplitude of the output signal based on the amplitude of the input signal. The horizontal axis
of the graph shows the different possible levels of the input signal – from -50 dB to 0 dB.
Here, 0 dB is the maximum input signal (i.e., since this is a digital processing effect, this is
the maximum signal that can be recorded digitally, given the sampling resolution). Usually,
-60 dB is considered silence. The vertical axis shows the ratio of compression or expansion
applied to each input signal. The compression / expansion ratio is between 10:1 and 1:10.
The points on the graph show where the compression ratio changes. You can click on points to
select them (the selected point will be shown in white; others will be in yellow). You can
drag points to move them. You can also click anywhere on the graph to create a new point.
(Points are removed with the Remove and Remove All buttons explained below).
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Threshold: Use these controls – the box and the slider – to set the threshold of the selected
point in the compressor. Many simpler compressors have only one threshold. This compressor
allows several threshold points and, consequently, several compression / expansion ratios
between these thresholds. You could, for example, expand (make louder) the quiet parts,
compress the louder parts, and leave the middle amplitude parts unchanged. As in the graph
above, the threshold is measured in decibels and each threshold point can be placed anywhere
between 0 dB and -50 dB.
-
Attack: Use these controls – the box and the slider – to set the attack of the compressor.
The attack is the time it takes for the compressor to change the amplitude of the signal so
that the compression / expansion ratio moves from 1:1 to the needed compression / expansion
ratio. The attack is measured in milliseconds (ms) and can be between 0 ms and 200 ms.
-
Release: Use these controls – the box and the slider – to set the release of the compressor.
The release is the time it takes the compressor to change the amplitude of the signal so that
the compression / expansion ratio changes from the needed compression / expansion ratio back
to 1:1. The release is measured in milliseconds (ms) and can be between 0 ms and 2000 ms.
-
Compress / expand ratio: Use this slider to change the compression / expansion ratio of the
selected point in the graph. The selected point is in white (all other points are in yellow).
The compression / expansion ration can be between 10:1 (compression) and 1:10 (expansion).
-
Output: Use these controls – the box and the slider – to give additional gain to the output
signal of the compressor. This gain is measured in decibels (dB) and can be between -20 dB
and 20 dB.
-
All bands: Click on this control to make all three compressor bands the same. The compressor
will adjust the parameters of the second and third frequency bands, so that they are the same
as the parameters of the first compressor band.
See Effects for additional notes on: where Orinj effects can be
used, using boxes and sliders that impact the same parameter (such as the box and slider for the
compressor attack), applying effects to mono and stereo waves, and using effects during playback.
See Working with effects for additional information on
creating, modifying, moving, removing, and processing effects.