Specifications

Chapter 18: Smack! 109
Using the Smack! Side-Chain
Input
Smack provides side-chain processing capabili-
ties. Compressors typically use the detected am-
plitude of their input signal to cause gain reduc-
tion. This split-off signal is called the side-chain.
However, an external signal (referred to as the
Key Input) can be used to trigger compression.
A typical use for external side-chain processing
is to control the dynamics of one audio signal
using the dynamics of another signal. For exam-
ple, you could use a lead vocal track to duck the
level of a background vocal track so that the
background vocals do not interfere with the lead
vocals.
To use an external Key Input to trigger
compression:
1 Insert Smack! on a track you want to compress
using external side-chain processing.
2 On the audio track or Auxiliary Input that you
want to specify as the Key Input (the signal that
will be used to trigger compression), click the
Send button and select the bus path to the track
that will use side-chain processing.
3 In the track that you are compressing, click the
instance of Smack! in the Inserts pop-up menu.
4 In the Smack! plug-in window, click the Key
Input menu, and select the input or bus path that
you have designated as the Key Input.
5 Begin playback. Smack! uses the input or bus
that you selected as a Key Input to trigger its ef-
fect.
6 To fine-tune the amount of compression, ad-
just the send level from the Key Input track.
7 To tailor the side-chain signal so that the de-
tector is frequency-sensitive, use the Side-Chain
EQ filter (see “Smack! Side-Chain EQ Filter” on
page 106 for more information).
8 Adjust other parameters to achieve the desired
effect.
RTAS plug-ins do not provide side-chain
processing when used on TDM-based sys-
tems. If you want to use side-chain process-
ing, use the TDM versions of plug-ins on
TDM-based systems.
The Side-Chain EQ filter lets you tailor the
equalization of the side-chain signal so that
the compression becomes frequency-sensi-
tive. See “Smack! Side-Chain EQ Filter” on
page 106 for more information.
The Key Input must be monophonic.
When you are using a Key Input to trigger
compression, the Input control has no effect
on the amount of compression.