There is a sound that bassists of live bands that jam a lot but are largely influenced by electronic music (disco biscuits and related projects especially), and I have been trying to put my finger on what this sound is for a good while.. sometimes it involves envelope filter or inverse wah tones, but I think more than this is a really sub-bass sound where maybe the mids are cut out, but there are some slightly "airy" overtones combined with a really deep sub sound. It's more of a subtle effect than a straight env. filter, and sounds like it's sort of replicating the bass in techno music or electronic dub music. Sorry for the non-technical description, but any idea what pedals are being used? Maybe a really versatile env. filter? If I can find a good example, I'll post it.