@Loz makes excellent suggestions.
Since everyone’s workflow is different, I’d suggest as an alternative you can use MIDI CC’s to affect the synth, effectively turning the volume up and down and/or all parts in between. The following applies if you are using MIDI to control MIDI Synths and not CV. I don’t CV, so can’t help you there. Sorry.
Keep in mind that a “long lengthed note” is actually 2 discrete MIDI Events: a Note On, and a Note Off which is sent from the sequencer after the period of time indicated by the note length ‘recorded’ and constrained by the MIDI Clock.
So, there isn’t any ‘data’ to Zoom in and adjust.
However, once you set a long note, or a short note with a Sustain Event (CC64), you can often modulate the synth via MIDI CC’s if your synth can respond.
Common similar techniques might be a MIDI “stutter”, where between the Note On and Note Off Event you send a series of CC07 (Volume) or CC11 (Expression, if your synth responds to that) that basically change the volume (no sound = volume 0). Using MIDI CC’s you can achieve just about exactly what you’re looking for if I understand correctly, althought Loz’s suggestion is much easier if the effect to implement especialy if what you want is a regular and repeated change of Note information.
Some things to keep in mind:
- MIDI Data is slow, so enforcing many extremely short events can be problematic.
- MIDI Data is sequential, so if you have many events happening around the same time, well…it’s like drinking a cherry milkshake through a straw and sucking up a chunk of cherry
- MIDI is just a series of commands being sent to your synth. What the synth does with those commands is dependent on how you patch the synth. Separating out these concepts can yield some exciting and creative applications, if you’re into that sort of thing.
Again: If I understand what you’re thinking of doing, which seems similar to how I used a DAW years ago (throw a whole bunch of loops and tracks that sounded good together, loop them, then carve them out to build a structure, then season with modulation, etc), you might find it doesn’t quite apply to MIDI sequencers.
But there’s an even better chance I don’t understand your OP at all.
tl;dr - Put in your long notes and then use CC07 or CC11 (or one specific to your synth that might be more appropriate) to modulate via the steps at any Zoom level.