bt's been known to fake his live performances though
he is? where did you read that? from the times I have seen him live the guy has done his set live pretty much to the tee - remixes, glitches, messups and all. if I see him at a local gig i might ask the guy if there is truth to this..lol
its pretty much common knowledge at em411, livepa.org, dancetech and other production sites that the major players (chems, crystal method, bt, prodigy) mostly run off a dat with some triggering and knob twisting going on...orbital and autechre are one of the few who actually do it "live"...of course how live is "live" ba talaga when we're talking sequencers etc?
the reason being is that these guys have a huge operation going on and any live mishaps could result in less than favorable reviews which could damage their rep, theres just too much at stake to have a bad show...hence the reliance on dat
"the guy has done his set live pretty much to the tee" well see that would explain a lot...bt's music is really intricate and it would be a logistical nightmare to pull of every little tweak and stutter live...of course everyones using ableton now so i imagine that makes it much easier and they are probably doing a lot more "live" now
the epitome of live electronic for me is someone like squarepusher, it seems like he plays a lot of prerecorded tracks but theres a lot of live bass improv going on and live fx freekery
some things that i would like to note just to clarify things: since you mentioned Orbital, there is a bit of info I know about the group's live rig because they are one of the few electronica groups that still use a hardware sequencer for things that can't be played live with hardware synths. the model that they use is particular, the Alesis MMT-8 (KitC might know about these), which is basically like a drum machine that loops pre-produced loops that you use in tracks from the studio. Orbital are not alone in their use of hardware sequencers and the extent of how much is ona sequencer depends on what you you deem as the foundation of your tracks that you can play over with your synths.
the live use of sequencers by electronic acts is what sets people apart from being just plain DJs. so if you don't play records and do live remixing, this is as close to "live"playing as you are going to get. also, people might run audio off a dat but as far as I know you can't trigger audio off a dat because a dat is pretty much like a casette tape in principle. now, you could do triggering with rack mounted samplers like the stuff Akai has around that are still being widely used and I have done that with my midi keys and v-drum triggers.
"the guy has done his set live pretty much to the tee." this statement was meant to explain that BT has stayed pretty much true to the live ethic that has helped him gain fans, ie. he does live remixing and extended versions of songs with generous amounts of edits. he does DJ gigs once in a while too but his rig has stayed consistent (to a tee) when he does live shows. i saw his laptop symphony show and his setup is becoming smaller with only particular pieces of kit to do stutter edits live using a system similar to the laser MIDI detector on the Roland MC-505. as far as I know, BT, Electric Sky Church, Telefon Tel Aviv, DeepSky, Orbital, The Crystal Method still do a lot of live shows that vary quite a bit from set to set and use quite a bit of hardware gear.
Now there will always be elements that will need to be run off a sequencer, this much is inevitable. i know BT runs stutter edits with a live hardware interface and I can only imagine how easier it would make my life if I had that tool. If I could do that, I wouldn't run audio for stutter but manipulate it live instead. Stutter edits, depending on the syncopation of the clips, will take me anywhere from 30 minutes to two hours to complete...sheeeesh.
for me, the epitome of a live electronic show is Aphex Twin. A close second is Tokyo's Boom Boom Satellites. I saw these guys at the Zep in Tokyo and they are absolutely sick.