issue with midi over usb - polyphonic play

[stimming]

hey guys, on 1.9 and 2.0 there is an issue with midi over usb:
when using an external usb keyboard (I tested mpk mini and arturia microlab) the usb-midi input drops out after some time of polyphonic play - I would guess its maybe 800 notes being played and then no midi input is taken further. this happens with seqs being in midi moder or in keys mode and doesnt matter if an internal pad is being controlled or an external synth via midi.
its pretty simple to find out: just play polyphonic stuff for about 2min with an external usbmidi keyboard and then it will drop off with no note-off signal being sent.

maybe an internal midi buffer overrun?

allow me to thank you for fixing this in advance

[stimming]

oh, and: removing and re-plugging (is that the right word?) the external keyboard activates midi over usb again.

[shankiphonic]

I reported something similar in the firmware comments thread. Arturia keystep in my case. Unplugging and plugging usb back in revived it. I believe it was @steve who pointed out that bb cannot reliably meet the power requirements of the keystep. So first thing would probably be to check if it’s stated somewhere on the forum how much power the bb can reliably offer to controllers over usb/compare the power draw requirements to those of the keystep….
As it happens, I didn’t really use usb midi on the bb until now. I have a an iRig Keys that does usb midi and can also power itself with AA’s. So it’s time to dust that off, I guess.

[stimming]

I found the same behaviour on the akai lpd8 (which reacts very very well together with the blackbox, its surprisingly good, really!) - after certain amount of note inputs it doesnt work anymore. I strongly guess it is some kind of internal buffer override which unfortunately makes the bb unusable with midi over usb.

[euklides]

My Launchpad MK3 PRO dies if used over USB. Hit play or pause and it has to be unplugged and replugged to work. Is this some power issue? Incredibly sad to have to use separate power, MIDI dongles and an old school MIDI cable to use them together.

[Georges]

a USB Y cable might actually work, use the data signal with the bb and the power part with your PSU

[Steve]

The blackbox only provides enough power for low-power devices per the MIDI spec. Unfortunately, Novation did not include a Low-Power mode. Likey because this device does a lot. However, on page 58 of the manual you find this:

The LED brightness level slider has 8 levels, from minimum to maximum brightness. The brightly lit white pad indicates which level is currently selected. Certain USB host devices may not provide sufficient power to fully boot Launchpad Pro. The power consumption may be reduced by using lower brightness levels, allowing these devices to fully boot Launchpad Pro.

No guarantee that this will solve your issue but it might be worth trying.

[euklides]

The blackbox only provides enough power for low-power devices per the MIDI spec. Unfortunately, Novation did not include a Low-Power mode. Likey because this device does a lot. However, on page 58 of the manual you find this:
No guarantee that this will solve your issue but it might be worth trying.

Thanks. I'll try it. Does it matter if I power the Blackbox from a batter or the wall plug?

[euklides]

The blackbox only provides enough power for low-power devices per the MIDI spec. Unfortunately, Novation did not include a Low-Power mode. Likey because this device does a lot. However, on page 58 of the manual you find this: No guarantee that this will solve your issue but it might be worth trying.

Hey Steve. I found a way to fix the issue. Before the Blackbox would stop receiving data from the Launchpad Pro mk3 if you changed the play state (stopped or started the BB). When I disabled MIDI RX/TX on the Launchpad I could start/stop the BB without any issue, still hearing the Launchpad.

Then, and this is weird, once I re-enabled RX/TX on the Launchpad, the BB doesn't mind. It syncs. It works. No drop-out. I can unplug and replug USB, and it keeps working. I don't know enough about MIDI or drivers to understand what might cause a glitch like this... But at least it was an easy fix on the user end.

EDIT: Seems the problem eventually returns if I have BOTH RX and TX enabled on the Launchpad over USB. If I have it set to only receive but not to send, it works fine. MIDI feedback???

[Steve]

That makes more sense. I would bet you have a MIDI loop in there.

[duncandisorderly]

I've used my bb as a host for a blokas midihub, & attached other stuff to that (couple of keyboards- an x-mini or whatever it is, & a korg wavestate), + bluebox as clock source & a polyend tracker as another sequencer. never had any dropouts. I have been using a charger/supply I got from amazon, originally for charging a bunch of ipads & phones while we were on holiday with the kids. it has what it calls "high power" or "fast charge" outputs.... anyway, haven't had any of this kind of problem. once, the bluebox locked up after being on for about eight hours, but I think that was something else. this sounds like a buffer filling up, possibly as a result of a loop or active-sensing or summat, rather than power supply.