Total Posts: 74
OK I'm probably talking to myself here but I think I've just answered my own question and I think the answer is yes. I'm posting how I think it would work in case this helps anyone else trying to do the same thing - as I've seen this question raised and never fully answered over at Loopmasters.
While I still can't find a hardware MIDI sequencer (correct me if I'm wrong here) that will actually let you control the transport controls, 'rec', 'play', 'stop' etc. using MIDI from a controller (in my case my DrumKat), a better way of doing this occurred to me.
This all assumes you're playing to a click.
On the MV, in loop recording mode you could set up a loop of a given length, e.g. four bars, such that when the transport reaches the end of the phrase it will loop round for another pass while still recording. With 'overdub 1' mode selected it will overdub, while outputting the MIDI you've already recorded.
Set up two kits on your controller, outputting the same MIDI notes (so the same sounds will be triggered from your sound source) but on different channels, say ten and eleven; set up your sound source to respond on all channels; and set the MV to respond on channel eleven only. I'm pretty sure on my DrumKat there's some kind of 'kit chain' function where I can toggle between two kits by hitting a pad, or alternatively set up a pair of pads to output program changes that the Kat will respond to itself.
Before you pick up your sticks and start your performance, activate record and start the sequence. Then start off playing on channel ten. Then whenever you want to 'punch in' (figuratively speaking - because of course you are 'punched in' all the time - you're just not playing anything that the sequencer hears) you simply hit the pad that changes your patch on the controller from the one that outputs on channel ten to the one that outputs on channel eleven. Record for as much of the four bars as you want, then 'punch out' again by toggling back to the other kit. Then, every four bars, you'll hear what you played while you were punched in. And whenever you want to add more, you can just punch in and out again to overdub.
So the only big limitation is that you have to decide how long your loop is going to be before you start playing.
If you can't set your sound source to receive on all channels there are other ways round it: -
1) If you've got a nice MIDI interface like me, with inputs to the interface from the controller and from the MV both routed to the output that goes to the sound source, you could set it to rechannelise all MIDI that goes out of the output to the sound source on track eleven to track ten, and have the sound source just respond to track ten only.
2) If you've got a nice MIDI controller like me, rather than having one patch output only channel ten and the other output only channel eleven, you could layer up notes such that one patch outputs ten only and the other outputs both ten and eleven.
2) Rather than using two different MIDI channels you could have the two patches on your controller both outputting on the same channel, but one of them outputting (say) notes 36, 40 and 42 from the three pads that you're using to play your rhythm, and the other outputting 46, 50 and 52 from the same three pads. Then simply assign the same three notes to each set of three numbers in your source, but using the 'recording filter' in the MV8800 set it to ignore one of the sets of three notes.
And of course if you've got midi processing kit you can do all sorts of clever things to start and stop playback of your loop on the fly - e.g. set note 70 (for instance) coming from your controller to be converted into a 127 CC value, and note 71 to be converted into a 0 control value (I can do this sort of thing in my Fireworx), then set the level parameter on the sound source to respond to that CC range - so when you hit one pad the level is switched up to full and when you hit the other it's switched down to zero, effectively 'starting' and 'stopping' playback (though of course actually it's still playing even when 'stopped', you just can't hear it).
If on the MV sequencer you can have several tracks recording MIDI at once, you could of course have several loops of different lengths going to different sound sources all at once, all with independent 'start' and 'stop' controls, and all controlled on the fly, during your performance, from your controller! Nice.