If you want a great envelope filter with simple controls, check out a Pigtronix Bass Envelope Phaser. Just 2 knobs and a switch, but it does everything from subtle vowel sounds to dripping Mutron wetness.
They stopped making them, but you can still find one for under $200 pretty easily. I'm always singing the praises of mine, it's my favorite modulation pedal.
They stopped making them, but you can still find one for under $200 pretty easily. I'm always singing the praises of mine, it's my favorite modulation pedal.