Fractal Axe-Fx - Multi-Band Compressor (Ultra Only)

The Effects
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RATIO - Sets the gain expansion ratio. This is the ratio of input power to output power below the
threshold. If the input power is -40 dB and the threshold -30 dB and the ratio 2, the output power
will be -60 dB (two dB reduction for every one dB below threshold).
DETECT - Selects the type of detector: RMS or Peak. RMS is smoother and is recommended for
slow attack settings and special effects use. Peak responds faster and is recommended for use as a
noise gate.
SCSEL - Selects the sidechain input source. NONE is the normal setting and selects the block input
(sum of the rows feeding the block) as the sidechain source. The other settings allow isolating a
single row or main input as the sidechain input. The other rows are summed as usual. By using a
row or main input as the sidechain input you can use the Gate / Expander as a ducker or de-esser.
You can also choose either of the main inputs as sidechain sources, i.e. Input 1 or Input 2.
LOWCUT - Sets the frequency of a highpass filter on the sidechain input.
HICUT - Sets the frequency of a lowpass filter on the sidechain input.
Multi-Band Compressor (Ultra Only)
The Axe-Fx Ultra contains a three-band compressor that is great for mastering or compression of a
whole mix. It also works great after distortion to help thicken the tone.
The basic principle of the Multi-Band compressor is that the input is divided into three bands using
a crossover. Compression is applied to the individual bands and then the outputs recombined. This
allows isolating bands of the input material and applying different amounts of compression. Multi-
Band compression is the de-facto mastering tool and can really improve the final mix.
Parameters
FREQ1 - Sets the crossover frequency between band 1 and band 2.
FREQ2 - Sets the crossover frequency between band 2 and band 3.
Each compressor section has its own menu page with the following parameters:
THRSH - Threshold control. The threshold at which output compression starts to occur.
RATIO - Sets the gain reduction ratio. This is the ratio of input power to output power beyond the
threshold. For example, if the threshold is -40 dB, the input signal is -30 dB and the ratio is 2.0 the
output will be -35 dB.
ATT - Attack rate. Sets how fast the compressor reduces its gain once the threshold is exceeded.
Higher values equal faster response.
REL - Release rate. Sets how fast the compressor restores the gain once the signal has fallen below
the threshold.
LEVEL - Sets the output level of the band.