Specifications

Focusrite D2 and D3 Plug-Ins Guide16
the output will increase only by 1 dB. With a com-
pression ratio of 4:1 for example, an 8 dB increase
in input will produce only a 2 dB increase in out-
put.
The D3 Limiter
The D3 limiter operates as a fast-attack compres-
sor with a high compression ratio. It does not at-
tack instantaneously or look ahead in order to at-
tack ahead of time, but instead uses a very fast, 1-
millisecond attack time. As such, the D3 is not a
“brick wall” limiter, but limits the overall dynamic
range of signals in a sonically-pleasing way.
Like the Compressor, the Limiter is activated
when the signal exceeds the user-selected thresh-
old. The Limiter then compresses any signal above
the selected threshold down to the threshold limit
that you have set.
Side-Chain Processing
Compressors and limiters generally use the de-
tected amplitude of the input signal as a control
source. Other signals can also be used as a control
source by using a key input. With de-essing, for
example, a frequency-modified version of the in-
put signal is used as a trigger. This is known as
side-chain processing.
Side-chain processing allows the D3 compression
or limiting to be controlled by another independent
audio signal—typically another Pro Tools track. In
this way you can compress or limit one track’s au-
dio using the dynamics of a different track’s audio.
Using the D3 Plug-In in Stereo
In stereo configurations, all D3 controls except the
Input Level affect both channels of the stereo sig-
nal. The D3’s RMS detector (which derives the
control signal that drives the dynamics processing)
uses a composite of the two channels. Because of
this, when stereo processing occurs, there is no im-
age shift when signal levels differ between the two
channels (since the composite control signal drives
processing for both channels).
Adjusting Plug-In Parameters
You can adjust plug-in controls by dragging the
control’s slider or knob, or by typing a value into
the control’s text box. Additionally, some plug-ins
have switches that can be enabled by clicking on
them.
To adjust a plug-in control:
1 Begin audio playback so that you can hear the
control changes in real time.
2 Adjust the controls of the plug-in for the effect
you want. Refer to “Editing Parameters Using a
Mouse” on page 16 and “Editing Parameters
Using a Computer Keyboard” on page 17.
Closing the plug-in will save the most recent
changes.
Editing Parameters Using a Mouse
You can adjust rotary controls by dragging hori-
zontally or vertically. Parameter values increase as
you drag upward or to the right, and decrease as
you drag downward or to the left.
Keyboard Shortcuts
 For finer adjustments, Control-drag (Windows)
or Command-drag (Mac) the control.
 To return a control to its default value, Alt-click
(Windows) or Option-click (Mac) the control.
Adjusting rotary controls