As Got2SadowdkyNYC says, there's no reason for active electronics to have any impact on an envelope filter. Ignore the people who say that active basses are louder than passive ones as that's false. SOME are, but unless you're cranking all the EQ bands all the way, most active basses don't have as much output as an early '80s passive G&L with the MFD pickups.
With ANY bass you'll have to spend a bit of time tweaking how the envelope filter responds to how YOU set up the bass and how YOU adjust the EQ, how YOU attack the strings, and how YOU want it to sound. I went through an envelope filter journey about 10 years ago. I had and gigged with an old MXR, a DOD FX-25(?), an EH Q-Tron, a Boss AutoWha, and then got an EBS Bass-IQ. That's where my search ended.
Now, my experience was that the Q-Tron was cool sounding, but really tweaky. The settings would vary a lot from night-to-night, it had an 18V power supply so I couldn't use it with the rest of my board's power supply, and it was almost impossible to find the right place where the envelope opened where I wanted it to and it still had the right volume for the band. Plus it was noisy. But that's just the old EH Q-Tron, it had nothing to do with whether I was playing my VS '62 Precision, my Hamer Cruise Bass, my pre-EB StingRay, or my Laklands.
John
