Max notes per clip == hardware limit?

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Hello and Merry Christmas!
Days 2 with my LoopA, I love it!
I currently use it as a USB midi slave to an Ableton Live session, driving hardware synths. The timing/mesure tracking is a treasure, and even in a tormented environment with conflicting midi clocks on a MIDI cable (yeah I tried), I experienced no freeze or weird note locks whatsoever… Pretty happy about the stability feeling I get here.

I tried to upload a first MIDI track to the LoopA but put a foot straight on what seems to be a software limit regarding the max number of MIDI notes I could input in a single clip: When recording notes for a while on a long 1024 steps clip, the recording stops.

After digging into the 2.06 firmware on Github I realized there is a limit of 256 notes per clip I didn’t see in the documentation (and if I understood correctly):

L1080

if (clipNoteNumber < MAXNOTES && (...) )

Despite the small garbage collection running just above this condition, I am stuck with this limit (and yeah if you ask, this MIDI voice is a bit overkill, it’s a plucky/rainy synth voice with… way too much notes but I wanted to try)

stuck at mesure 3 lol

Could you just tell me if this software MAXNOTES limit I am hitting is due to a hardware memory limitation? Could this limit be increased at some point?

Cheers!

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schematicwizard glad you like your LoopA so far! 🙂

Yes, the note limit of 256 notes per clip is both a usability as well as a hardware memory limit - having much more notes in a clip would make the tiny screen (in contrast to a DAW) with only 256 horizontal pixels quite overcrowded (always the full clip is shown horizontally, with all notes visible). I can jam and record on my MIDI keyboard (using both hands) for quite a long time (one or more minutes, depending on the speed), then cut out the relevant areas that are loop-worthy and edit them afterwards to correct the inevitable wrong notes 🙂. The hardware limit is because the microcontroller only has 192KB of total RAM (ca 50.000 times less than a current “standard” DAW computer) and LoopA has 36 clips in memory as well as associated high-resolution CC data per clip. Still everything should be snappy (i.e. SD card loads, note edits, screen updates and so forth) while the hardware is driven by an efficient 330 milliwatt MCU, that can be powered by a USB power bank for hours.

An option to record such a complex sequence would be to record to mutiple scenes, and switch between them (it is possible to switch scenes via remote CC command). Another option would be to record to clips in multiple tracks and add “silence” at the beginning of each other track clip, so that the sequence would start on the first track, then be continued in the second, and so on.

Hopefully this was helpful and explains what is going on behind the scenes.

Best regards and have a good holiday time!
Peter

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Hawkeye Thanks for the detailed explanations. Using multiple tracks is a very good idea I didn’t have, I’ll try this option, thanks!

(If other users feel stuck with this in the future, maybe an alternative for you would be not to divide your 9 216 notes limit per clip (256×36) but to implement it for the whole opened project/all clips at once? But I may not have all your other code/hw constraints in mind, just an idea after reading this 😉 )

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@schematicwizard this is a very good idea - a shared memory pool would be a good expansion option for the future - although it comes at the cost of mapping every “pool note” to a clip, which might just be doable with the available RAM (but then at the cost of other expansions like the often-requested song-mode), or by rearranging the pooled notes in clip order and tracking pool start/end position per clip. One implementation option would come at the cost of a higher memory footprint (we’re already quite at the limit, many software releases since LoopA launch), the other with more MCU processing overhead. It is doable in theory, but a difficult task, best to leave that can of worms closed at the moment 🙂.

Best regards and enjoy!
Peter