User Manual

3.4. Understanding the Comp FET-76 Signal Flow
The Comp FET-76 is what's called a "feedback compressor". This means that the detection
signal comes already from the Gain Reduction circuit. The signal flow is a little more
complex than what could be expected, due to the Advanced Mode features, especially those
related to the Advanced Side-Chain Control. This allows for several special detection modes,
some of them taking advantage of Mid/Side signal encoding.
As the signal enters the plug-in, it is immediately split in two paths:
1. The "main" signal path. The signal on this path is compressed and processed.
2. The "bypass" path. The signal on this path is sent without any processing to a
mixer just before the FET-76's output. The "Mix" knob on the front panel lets you
blend this unprocessed signal with the compressed signal.
If you are using Comp FET-76 on a stereo track, the first stop on the main signal path is the
optional M/S encoder. M/S stands for "Mid/Side" and is a way of processing audio where
only the "Mid" channel (the center of the stereo image) or "side" channel (the edges of the
stereo field) is processed. This is described in detail later [p.25] in the manual. Note that the
Detection Mode control knob is only available on stereo signals and is bypassed when using
a mono version of the plug-in.

♪: M/S requires a stereo signal to work. If FET-76 is instantiated on a mono track, M/S encoding and
decoding stages are bypassed and the Detection Mode control knob is hidden in the advanced panel.
After this stage, the signal is routed on to the emulated FET gain reduction circuitry. This is
the heart of the circuit and where the actual compression takes place. This is controlled by
the Gain Reduction Control circuit.
If you are working with a stereo signal, the next stage is the M/S decoding block.
After passing through the Gain Reduction circuit, the signal is split into two more paths:
1. The main path goes on to the M/S decoding block. This is where your signal is
converted back into a regular stereo signal.
2. The second path (known as the "feedback" path) is sent back through a Source
Selector switch to the Gain Reduction Control circuitry. The Source Selector also
receives the external side-chain signal.
Comp FET-76 Signal Flow
Arturia - User Manual Comp FET-76 - COMP FET-76 OVERVIEW 9