Ok, the numerous other comments nonwithstanding, here's my take, also from a looper's perspective.We all know that music is as much about the silence as it is about the notes. However, when doing live shows, I often struggle with finding ways of stripping down the performance (I use an EDP or Boomerang when I loop). What do the members of this esteemed group do to help give silence her due?
From a looping perspective, I see three things here: 1. turn off the loop (and be able to restart it), 2. reduce contents of what comes out of the looper, 3. turning down the volume of the looper.ad 1: I've seen four different kinds of this functionality (but point 3 can be seen as another one). a) stop the loop (when you restart it, it starts from its beginning) e.g. Line6 DL4, b) mute the loop (when you unmute, it continues where it has run while being silent) e.g. EDP, c) pause the loop (when youpause, the loop continues right where you paused it) e.g. one option in Möbius and d) none at all (typical of delays used as loopers, but I seem to remember this was also true for the Headrush).
As I personally worked with Möbius a lot in the past, the one I used the most was mute (b), especially when using multiple loops in a defined timing relationship. Of course, the same behaviour as a) can be done by doing unmute followed by retrigger. An example how I worked with muting a loop and rests in what I played to it can be heard at the end of my track "Kekslogistik" http://moinlabs.bandcamp.com/track/kekslogistik - at the end, I do a kind of challenge/response thing between my playing and the (processed) loop.
If a), b) or c) makes the most sense of course depends on the musical situation.
ad 2: this is either turning off one of multiple loops or undoing. The EDP (and its bastard software sibling, Möbius) has for a long time been the only looper (I know of) which allows for multiple levels of undo and redo. Of course, you can (with a reduced amount of undo/redo levels) get the same result with something multitrack, e.g. the Repeater.
Of course, this also intersects with 1, namely if in the last section you were talking about muting individual loops of a multi-loop thingie. This can often be replicated with undo/redo sequences. On the other hand, the multitrack solution is the more powerful, but not as intuitive if you just want to remove or add the last two layers of overdubs.
ad 3: this is always possible if the looper is setup in a send effect setting, and as far as I know also for an inserted looper for all devices, as they all feature a loop level control of sorts. Of course, turning the loop volume to 0 is identical to the mute option of section 1.
This is also something I hadn't done enough in the past - which is odd, because I always had the loop volume mapped to a pedal in all of my more complex setups (Repeater, then Möbius). (An example of me using this is "Deine Mutter hört Metal" http://moinlabs.bandcamp.com/track/deine-mutter-h-rt-metal). This can also be interesting for another aspect. Of course, if you play an instrument louder or quieter it usually also sounds different. For that reason, it's fun to play to a loop at full volume (either unisono or another voice, but this works best when playing the same instrument and something similar), then turn down the loop volume and play your instrument much quieter.
So much for now, Rainer -- http://moinlabs.de Follow me on twitter: http://twitter.com/moinlabs