here’s an idea i find myself using a lot in compositions. thought i’d share it in case it helps anyone. (btw, i have been meaning to create a demo of this idea with video or at least audio, and haven’t got round to it … if anything’s unclear give a yell and i’ll get off my ass) 
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for a long time, arpeggiators never attracted me much. occasionally they seemed useful for idea generation, but nothing i’d ever turn loose onstage, because the results didn’t reliably sound like music to me.
so when i got a monomachine i avoided the arp and focused on sequencing exactly what i wanted, but then i ran into the opposite problem – the resulting loops were completely predictable. sure, i could keep things moving with tweaks and by muting other track elements, which works fine, but the melodic sequence itself would get old pretty quickly if i didn’t keep changing patterns, and you’ve only got so many of those in a snapshot.
what i found myself wanting was a way to introduce just the right amount of melodic randomness into a pattern, to find the balance between repetition and variation. after awhile i realized combining the mnm’s main sequencer with its arp sequencer could help – they just needed to limit and complement each other.
the approach i find most useful occurred to me when i was trying to emulate funk bass players, who often play the same essential riff again and again, but incorporate little variations here and there to keep it fresh to the listener’s ear. it depends on the SID random arp, which only runs until it hits a note that is not a chord and then stops.
to begin, create a 1-measure house drum groove (with any gear you like). then with the mono, lay down a simple funk bass part atop it … a “basic riff” made of 2-3 strong, key-defining notes (make them all the scale’s root and flat third, for example). just to illustrate this idea, put this riff in the first couple of beats of the measure.
if you loop that, of course it gets boring in a hurry. a common funk solution is to put a brief turnaround lick that is different every time, at the end of a phrase. so find a sequence for the last part of the phrase that sounds good even with different notes on its trigs. for example: place trigs on steps 13, 14 and 15. now if you put either the scale’s 5th or flat 7th on any of these three hits, in any order, the entire line will imply a m7 tonality.
it’s still boring if the sequence is the same every time. so that’s where the arp can help.
the trick: for the end of the phrase, now put a trig only on step 13, not 14/15. program it to play a chord made of the two new pitches, both the fifth and flat seventh. then open the arp sequencer menu. make sure the arp’s first 3 steps are green, the 4th and later ones should be red. important: make it a SID random arp, playing at x6 speed.
the arp will now sound on the same three steps that your turnaround lick originally sounded. but now as the sequence loops, you should hear a different 3-note lick every time after your “basic riff”, which should play the same way every loop. (none of the single notes in the basic riff should trigger the arp, just the chord hit of step 13.)
with a little adaptation, you can use this idea anywhere and with any style. the arp becomes a little rhythmic motif with varied pitches that you can drop into a longer phrase. by starting it on different steps in different measures surrounded by different unchanging notes, it’s a powerful tool.
examples: write two mnm tracks with lines that take advantage of this idea and they can run for a long time while you tweak something else. or go into the arp menu while you jam and switch up the red and green notes to vary that track’s arp motif itself. voila, a pattern that doesn’t get boring nearly as quickly.
one warning: the idea works only when looping a single pattern, as the mnm arp resets itself every time a new pattern begins. if you chain two patterns, even two that use the same kit, the arp will play the same sequence each time.