currently it's not possible to modulate the Filterbank with an envelope.
in the Matrix, I can select an LFO or a controller to modulate the filterbank frequency. However, when you select envelope 3 or 4, nothing happens.
I know I can use an LFO in envelope mode, but this doesn't offer the same functionality a real envelope has!
I would appreciate it if you add this functionality in a future update. it's a relatively small tweak, but it would make a lot of difference!