Compressor block

Compressor/Dynamics: in the owner's manuals

• Axe-Fx II: 5.4 Compressor [CMP]
• FX8: ...
• AX8: ...

Compressor/Dynamics: supported by which Fractal Audio products?

• Axe-Fx II: yes.
• FX8: yes.
• AX8: yes.

Compressor/Dynamics types

• “Pedal 2” uses a different algorithm which is smoother and pumps less.
• CPU usage by both "pedal" types is much less than the "Studio" type.
• The Dynamics algorithm allows compression or expansion with a single control. When the Dynamics parameter is set to negative values the block compresses the signal, when set to positive values the block expands the signal."
• The AMP block has a built-in output compressor (OUT COMP parameter). You can use this instead of a separate Compressor block. It does increase CPU usage.

Position of Compressor/Dynamics block on the grid

• Placing the Compressor block after the Amp block makes it interfere less with the amp dynamics.

Compressor/Dynamics and X/Y switching

• For X/Y-switching in the Compressor block you need the Axe-Fx II XL or XL+, FX8 or AX8.
• There's no MIDI CC available for X/Y switching in the Axe-Fx II XL/XL+.

Compressor/Dynamics Mix parameter

• Compressors are used mostly as a 100% wet effect. But there are compressors with Blend or Mix controls. These can be simulated by using the Mix parameter.

Compressor/Dynamics Sidechain Select parameter

• You can use the signal that enters the grid to feed the compressor, even if the compressor block is placed further upon the grid, through the Sidechain Select parameter (Studio mode only).

Compressor/Dynamics Release parameter (Pedal mode)

• Cliff's comments:
  • "Pedal compressors typically have very long release times so the time is scaled by 10 for pedal mode. The time in studio mode is accurate to within a microsecond." source
  • "The times are the classic "time constants" for analog circuits, i.e. the time it takes for a signal to settle to 37% of it's final value (e^-1)." source

Compressor/Dynamics Emphasis parameter

• Since the Pedal mode does not have a side-chain, this allows for a similar function by pre-emphasizing the high frequencies prior to compression and then de-emphasizing them after.

Compressor/Dynamics Lookahead parameter

• The default Lookahead value has been changed to 0 in firmware 16.x, because of detector improvements.

Compressor/Dynamics Fast RMS

• The “Fast RMS” Detector type in the Studio Comp mimics the fast detectors in classic rack-mount compressors.

Using Compressor as a limiter

• There's no dedicated brickwall limiter in the unit, but the compressor can be used as such. From the manual: "Setting the RATIO to “INFINITY” turns the compressor into a “limiter,” reducing any level above the threshold to the threshold, applying a sort of “ceiling” or “brick-wall limiting” above which nothing can rise." More information.

Compression tips and tutorials

• Radley's extensive and comprehensible Compression tips.
• Compressor FAQ.
• Danny Danzi's video tutorial.
• Dynamic range compression in Wikipedia.
• http://forum.fractalaudio.com/axe-fx-ii-discussion/59925-compressor-settings-country-twang-3.html
• Emulating the Solo Dallas Schaffer. More information