Korg KROSS Parameter Manual page 290

Effect Guide
Envelope Select
Source
Input Reverb Mix
Threshold
The "Envelope Select" parameter enables you to select whether
turning the gate on and off is triggered by the input signal level or
controlled directly by the modulation source. You can select from
Off to Gate2+Dmpr for the Source parameter to specify the
modulation source.
When "Envelope Select" is set to Input, the gate is controlled by
the level of signals that are the combination of the dry sound and
the reverb sound. When the signal level exceeds the threshold, the
gate opens and the reverb sound is output.
Normally, set "Input Reverb Mix" to Dry (the gate is controlled
only by the dry sound). If you wish to extend the gate time, set the
"Input Reverb Mix" value higher and adjust the "Threshould"
value.
282