Envelope filters have never been as popular as wah pedals despite sharing a lot in common. The beauty of an auto wah type setting is the genres it's spawned over the years around it, can you imagine funk and huge artists we know and love without Envelope filters, follows and auto wahs.
The Micro Q-Tron is a smooth envelope filter with the famous funky wah tone. The filter is controlled by its internal envelope follower which analyses the attack of your notes to directly sweep the filter's centre or cut-off frequency, stronger attacks produces a wider frequency sweep while softer playing produces more subtle effects. Use the Q control to make the effect more dramatic.