Knee; Attack; Hold - Alesis CLX440 Reference Manual

Knee

The
KNEE
expansion styles. When the CLX-440 is set for Hard knee, the
expansion ratio applies only to signals below the threshold level.
If the CLX-440 is set for Soft knee, the expansion ratio gradually
increases from 1:1 to the currently selected ratio over a range of
approximately 5 dB, so that the transition from unexpanded to
expanded is more gradual.
The difference between Hard Knee and Soft Knee is more
obvious at high expansion ratios (gating). Once the input signal
crosses the Threshold, the unit will compress the signal at the
full ratio level.
In most cases, you will want to use the Hard Knee setting for
Gating. This gives you a punchy sound on percussion and other
transient sounds. Soft knee expansion can be useful if the gate is
too noticeable. Softening the knee lets the gate gradually fade in,
instead of cutting in and out.

Attack

The
ATTACK
expander/gate to open. The range of this control is 0.02
milliseconds to 1 second. Short attacks are useful for percussive
sounds, where long attacks are good for melodic parts like
vocals and strings. Use a longer attack time when a short attack
is drawing attention to the sudden presence of noise. Use a
shorter attack when the input itself has a fast attack, such as a
snare drum.

Hold

The
HOLD
before expanding after the signal crosses under the threshold.
The range of this control is 0 ms to 2 seconds. This control is
useful for keeping the signal open a little longer before starting
the release fade. For example, if you want to hear more of the
room sound on a snare drum before clamping the gate back on,
you could increase the hold time.
CLX-440 Reference Manual
knob is used to vary between Hard and Soft knee
Hard Knee
knob controls the amount of time it takes for the
knob controls the amount of time the expander pauses
chapter 4 • basics of expansion
Soft Knee
37