Focusrite Red 1, Manual

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p a g e 6
The Red 3 is a 2-channel compressor and limiter. Each
channel can operate independently on two mono
signals, or they can be combined to act as a single
compressor and limiter on a stereo signal.
Compressors and limiters both act like automatic
volume controls, turning down the volume of a signal if
it gets too loud. The difference between the two is:
• A limiter sets an upper limit on the volume, and will
not allow the signal to go above that volume
• A compressor reduces changes in volume, so that the
dynamic range of the compressed signal is lower than
the dynamic range of the input signal
When you are getting to know the unit, particularly if
you are not familiar with using a compressor, use it on
a track that you are familiar with (for example, you
could run a favourite CD through the unit). Try all of
the controls in turn, and hear how they affect the
sound. Working with a familiar track makes
interpretation of the results easier. Note, however, that
tracks are already compressed for CD, so you may find
it hard to hear the results easily. If this is the case, try
using samples instead (if you have access to them), or
record your own track uncompressed and then play it
back through the Red 3.
There are two separate parts to the Red 3:
• The Compressor
• The Limiter
Compressor
A compressor reduces the dynamic range of a signal by
automatically reducing the gain when it gets louder
than a certain threshold. To understand a compressor,
you must understand dynamic range - if you do not, you
should read the following section about dynamic range.
Note that compression tends to even out a performance
(particularly of stringed instruments such as guitar)
since it stops the instrument getting very loud or very
quiet in the mix. When compressing hard, it also
reduces an instrument’s attack (again, this is most
noticeable with stringed instruments).
Dynamic Range
The dynamic range of a signal is the difference in
volume between the quietest and loudest parts: for
music, the dynamic range can be as wide as 120 dB.
Red 3
compressor/limiter
O/P
I/P
Limiting
Fixed Max
Level at Threshold
Old
New
+20 0 -10
Threshold
O/P
I/P
O/P Signal
I/P Signal
Level above
Threshold
Increases as
Ratio of the I/P
+20
+20 0 -10
0
-10
-20
O/P
Dynamic
Range
20dB
Original
Dynamic
I/P Range
40dB
Threshold