Pseudo-Envelope Controlled Filtering of a Hex Layer Tone

[AlenK]

Here's a way to emulate a resonant filter sweep with a Hex Layer tone. Others here have observed that the Wah DSP effect, whose filter has controllable resonance, can be applied to Hex Layer tones and to PCM tones to achieve the sound of a filter sweep. This is a way to automate that. Essentially, a step sequencer control track is aimed at CC#17, which for the Wah DSP effect will modulate the center frequency of its bandpass filter. The steps in the control track are arranged to emulate an envelope and the sequence plays through only once by virtue of another control track that addresses a knob programmed for the Step Sequencer Start/Stop NRPN command within a Performance.  

 

A custom Hex Layer tone is then created in which the Wah effect's built-in LFO is disabled. In order to more closely emulate a real filter envelope, an arpeggio is created that does nothing by itself (a "null" arpeggio). However, if SYNC is turned on (specifically using the "S/S" setting) then pressing any key for which the arpeggio is enabled will start the step sequencer, which starts the pseudo-envelope, and releasing the key will stop the step sequencer, which stops the pseudo-envelope. (Note that the arpeggio is enabled in a zone other than zone 1 because that zone will end up being silent. Wasting a zone is the unfortunate "collateral damage" for this technique.)

 

The Hex Layer tone, step sequence and arpeggio are then all called up in a suitably programmed Performance. The technique is fully described in section 6.6.2.1 of The XW-P1 Companion, Volume 1 (Rev 4 or later). This kind of filtering is called "paraphonic" because all notes pass through a single filter modulated by a single (pseudo) envelope. 

 

You'll find an example here.

Edited July 25, 2021 by AlenK