Midi knob "value jump" issue
  • dansonetti
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    Midi knob "value jump" issue

    by dansonetti » Wed May 19, 2010 2:15 pm

    Hello!
    Just bought myself the Akai MPD26 after I got back from MappingFestival -as a visitor- to make things easier for myself while using modul8. Yesterday I started to do some research for my perfect mapping setup and I stumbled upon an issue which I hope you guys can help me with.

    I've seen several topics involving endless rotary knobs (which the MPD26 has) and value jumping when switching to another medialayer.

    Example from Brain:
    you have used the knob to set the speed on layer 1 to 50%. then you switch to layer 2 where it is 100%. the rotary control is still set to 50%, if you start using it on layer 2 you will get a value jump down from 100 to 50%.


    *edit* in my case this would be the opacity of a layer

    I was wondering if there is a solution to this (not having to map each knob to a different layer since there are only 6 knobs on the MPD26) for sending the current value of a layer to the midi controller first as a startpoint for adjusting it's value. Unfortunately i couldn't find an answer that made sense to me. I hope someone has found a solution to this.

    I'm not a hardcore midi / scripting expert so a step by step answer would be much appreciated.

    thanks in advance!
  • mowgli_uk
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    by mowgli_uk » Wed May 19, 2010 8:18 pm

    If you have endless knobs you have to set up the mpd26 to output relative values rather than absolute.
  • dansonetti
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    by dansonetti » Wed May 19, 2010 9:38 pm

    Hmm the manual doesn't say anything about sending relative values but i does say this:

    The endless knobs on the MPD26 may also be used as an increment/decrement NRPN function. This allows
    you to use the knob to increment and decrement through parameters as opposed to sending an absolute
    value. Please note that the implementation of NRPN functions depends strictly on the software with which
    you will be using the MPD26. Consult your software’s documentation to find out how NRPN functions are
    supported.


    Modul8 manual doesn't say a thing about 'NRPN'.
    What I do noticed is that when it's in that NRPN mode and i try to map the knob to the opacity is when I turn the knob left it maps a different note than when i turn it to the right.

    I'm guessing that's a function that modul8 does not support? And the endless knobs aren't that endless?
  • Vibber
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    by Vibber » Thu May 20, 2010 3:57 pm

    One way around this problem is to have Modul8 send the updated values back to the midi device - so that that the device knows the current values when you have switched to another layer.

    This requires that your midi device can *receive MIDI*. I have googled it but I have not found an answer if the Akai MPD26 can receive MIDI.

    If this is the case let me know. I have a module for Modul8 (beta testing, not yet released) that addresses this issue - and it should be working for all devices with midi receive.
  • dansonetti
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    by dansonetti » Thu May 20, 2010 6:47 pm

    Concerning the USB connection between MPD26 and Computer the manual states:

    USB CONNECTION – Plug a standard USB cable into this outlet and into the USB port of your computer. The computer’s USB port will provide power to the MPD26. This connection is used to send and receive MIDI data to and from your computer and may also be used to send MIDI data from your computer to a device attached to the MIDI OUT port of the MPD26.


    Looks like there's still some hope left!
  • mowgli_uk
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    by mowgli_uk » Fri May 21, 2010 11:08 am

    dansonetti wrote:Hmm the manual doesn't say anything about sending relative values but i does say this:

    The endless knobs on the MPD26 may also be used as an increment/decrement NRPN function. This allows
    you to use the knob to increment and decrement through parameters as opposed to sending an absolute
    value. Please note that the implementation of NRPN functions depends strictly on the software with which
    you will be using the MPD26. Consult your software’s documentation to find out how NRPN functions are
    supported.


    Modul8 manual doesn't say a thing about 'NRPN'.
    What I do noticed is that when it's in that NRPN mode and i try to map the knob to the opacity is when I turn the knob left it maps a different note than when i turn it to the right.

    I'm guessing that's a function that modul8 does not support? And the endless knobs aren't that endless?


    what you mention is relative values
  • dansonetti
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    by dansonetti » Fri May 21, 2010 7:42 pm

    I don't think that's always correct, as far as my research goes NRPN doesn't have to be relative. It can also be absolute.

    I mailed Akai about it and this is what they had to say:
    Hello,


    The MPD26 pots are only able to send their absolute position.
    Having the endless knobs allows the knobs to have different values depending on the patches or banks that you are on without the need to physically reset their position. This is especially helpful when the knobs are set to use increment/decrement values to ‘limit’ their range to be within a specific set of numbers.

    Best Regards,
    xxx


    Technical Support Specialist


    I'm not an expert but when he said that they can only send their absolute position I guess I have to believe him ;D

    Also note that what I mentioned in a previous post:
    "What I do noticed is that when it's in that NRPN mode and i try to map the knob to the opacity is when I turn the knob left it maps a different note than when i turn it to the right."
    So I can only map 1 note to the opacity of a layer while NRPN requires 2 (increase/decrease). Or am I missing something?
  • barto
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    by barto » Sat Jun 19, 2010 11:28 pm

    I know the mpd 26 sends midi in/out through USB but it does also have midi in/out ports. I'm looking for an answer to this question too

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