Steppy pitchbend

defavltt posted Mar 2 '19, 07:34:

When I move the pitchbend wheel it goes in steps but when i move it very slowly its ok.
Am I doing something wrong. I used 3 different midi keyboards with a pitchbend wheel and its the same on all of them. The pitchbend isn't smooth! If theres a way i can fix this please tell me.


HansEhv posted Mar 2 '19, 21:38:

Weird. The pitchbend was made on a PI2 without this behaviour. I haven't encountered it yet.
You seem to loose part of the MIDI signals.
So a few things to check
Do you run on an SB image or a Raspbian or even other ?
What's version of your PI (1/2/3/3B) ?
Do you have a midi interface in between (and is that always the same one) ?
Do you use the serial interface?
Do you also encounter distorted sounds and/or clicks & plops ?
Without knowing anything of your setup (so I may very well be wrong), I'd say there is a midi interface in between that requires a closer look.

defavltt posted Mar 3 '19, 10:33:

Thanks for the reply

So im using a Rapsberry pi 3 B+ (not the latest SamplerBox image, because I can't get it running so im using an older version)
I don't have an interface between my midi controllers they're directly plugged in the Raspberry pi (Arturia Keystep, Korg Microkey, Korg Nanokey etc.)
Im not losing any midi data, but when I got the Arturia Keystep some midi information was not registering (hanging notes) but when I changed in the cmdline.txt the "dwc_otg.lpm_enable=0" to "dwc_otg.speed=1" that fixed the notes problem, (but my flash drive stopped working so I put my samples in the samples partition of the image SD card but if I put too many sample sets it doesnt work very well). And the pitchbend is still steppy on all of my controllers from the beginning.


HansEhv posted Mar 3 '19, 21:40:

Hi defavltt,
Thanks, this gives a possible reason:
By using dwc_otg.speed=1, the usb speed is lowered to usb1.1 value. This is slow.
So the pitch wheel might send its values faster that the usb port can receive and subsequently the SB script does not get all mididata - it misses the intermediate steps.
Another consideration: I understand the image your build is based on si old, so it does not support RPI3B+ due to incompatible drivers for the IO-chip. This may also be a reason of the box not doing doing things right and forcing you to lower the usb speed.
You could try to upgrade your image (which I presume to be Jessie based) partly for the "plus" hardware.
I've documented the way it worked for me on:
Keep in mind that I did so on a "clean" samplerbox image. You may already have done some things to make it work on 3B+ which might interfere with this method.

defavltt posted Mar 6 '19, 16:08:

Hi Hans,
The thing is that the pitch bend was steppy even when I first installed a clean SB image but that isn't that big of a problem right now.
Besides this im making a pocket sized synth that is using the SB image. Should I consider using a Compute module 2 or Compute module 1 (bare-bones / portless version of the Raspberry pi) I already have the compute module 3 but which one will work the best?
And the problem that I didn't use the latest SB image is that im not really familiar how it really works. Im mounting the SB image using Etcher but when I put it in the Pi and turn it on it doesn't work. Is that because it's not meant for the RPI3B+? Let me know if im doing something wrong.


HansEhv posted Mar 7 '19, 21:05:

Old images don't run on RPI3B+ at all. Some folks made it to startup by replacing start.elf, but that does not solve all incompatibilities = it works but not 100% OK. Depending on what you do this is a problem or not.

defavltt posted Mar 8 '19, 04:30:

Oh yeah I remember when I replaced the start.elf file. So that's where the all the problem come from. Can you give me a more in-depth instructions to installing a newer image?

HansEhv posted Mar 8 '19, 22:48:

Hi defavltt,
I dare not say that "this is where all the problems come from".

All three builds (Joseph's=original, Alex's and mine) have instructions on the respective sites (cannot post multiple links on this forum, but since you've downloaded an image, you must have been there..).
Detailed instructions for making older builds compatible with 3B+ are in my previous post March 3.



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