[quote name='Kev' timestamp='1375310022' post='2159741']
With regards to the Wonderlove, for me it was much better than the Xerograph as a classic envelope filter, but the expression pedal function was great for a wah pedal effect, but not much more.
[/quote]
The type of filter in the Wonderlove probably wouldn't give a steep enough cutoff for the filter sweep sound. I was just wondering if it was easy enough to put such a filter in a wah she'll would it be a worthwhile design exercise for this application. More research required...