Forum Rule: Always post complete source code & details to reproduce any issue!
Results 1 to 3 of 3

Thread: Guitar Amplifier MIDI Controller - Feasibility questions.

  1. #1
    Junior Member
    Join Date
    Jun 2020
    Posts
    1

    Guitar Amplifier MIDI Controller - Feasibility questions.

    Hi all,

    First post here. I'm considering building a MIDI controller to control a guitar amp modeler from Neural DSP, the 'Cali' model. According to my research, Teensy is preferable to Arduino here, because of native USB MIDI, if I've read correctly.

    Click image for larger version. 

Name:	fortin-cali-cover.jpg 
Views:	14 
Size:	91.5 KB 
ID:	20530

    I'll be building an actual box as close to identical as I can to this, including the same switches and knobs. Additionally, I may also build replicas of the 3 stomp boxes featured on the other tab in the program, but that is for further down the track. I'm planning to use this in practice and gig situations, so I will likely install my Focusrite Interface in the enclosure for going direct to a PA. Another idea is to build a matching 4 x 12 cabinet with power amp and speakers, so that I could plug into a cab for practice and onstage monitoring. These are all 'further down the line' ideas like the stompboxes.

    Question 1: the Bass knob is a push-pull pot, push in for Bass, pull out for Saturation. Can this type of potentiometer be used as a MIDI controller?

    Question 2: the 4 smaller switches (Thump/Hair/Violence/Bright) are all 3 way switches, but in the MIDI control page of the app, there is only one MIDI command - actually 3, one command each for the Clean, OD1, and OD2 channels on the amp. Unfortunately, even if MIDI can use a 3 way switch, it doesn't appear that I could use that to mimic the 3 different sounds each switch gives. So, it seems the simplest option would be a momentary switch to cycle between the 3 switch stages. Would that be the obvious way to handle this situation?

    Question 3: As above, there are 3 channels in this amp - Clean, OD1, OD2 - and a full set of MIDI commands for each, ie. Clean Bass / OD1 Bass / OD2 Bass. Is it possible to use a 3 way switch to change the MIDI controller between sending Clean, OD1 and OD2 commands?

    Question 4: If I've researched correctly, one benefit of Teensy over Arduino is native USB MIDI - am I correct in thinking that the end product will plug in and be treated like a commercial MIDI controller, without having to use the additional applications I've seen required for Arduino? I can't remember the names, but I've watched videos on Arduino controllers that needed 2 different applications to work..

    Question 5: I'm not sure if this is answerable without seeing the software and manual, but would it likely be possible for the Neural software to read the positions of the knobs when it is connected, and update the software amp's knobs to the current values on the MIDI controller's pots/switches? Perhaps some code that sends a message with all pot/switch positions on repeat?

    I appreciate any responses here, and if there's something I've missed, please feel free to let me know. Apologies for the long winded explanation, I tend to over-explain things.

    Edit: I will most likely also add some controls in the back of the amp to control the top section of the software - Input, Gate, Preset forward/back, Output.
    Last edited by Sedition; 06-07-2020 at 09:19 AM. Reason: Additional information.

  2. #2
    Junior Member
    Join Date
    Aug 2018
    Posts
    6
    Hi and welcome to the forum.

    This sounds like a great project!

    1. Yes, a push pull pot will work fine - the mechanics of a push pull pot are identical to using a 'normal' pot and a separate switch so the push-pull would be wired to the Arduino in exactly the same way. One thing to check for is the taper of the pot - I would say buying a linear taper and then implementing any audio/log curve in software is more flexible than using an audio taper pot.

    2.This is definitely doable (if I am reading it right). 3 position on-on-on switches can be used, the Teensy can then detect each of those three positions and send out the correct MIDI message - just because it is a single switch doesn't mean it can't send out a different MIDI message at each position; this is what makes doing this sort of thing with a Teensy so flexible.

    3. See 2

    4. Yep, absolutely - just plug and play; the Teensy will show up in your DAW in the same way any other MIDI device would.

    5. No idea if the software can 'request' that (probably not) but the controller could certainly send out the current positions during the 'setup' stage of the program, or with a 'reset' button or something.

  3. #3
    Junior Member
    Join Date
    Sep 2020
    Posts
    4

    Simple question

    Assuming you have figured out how to send messages from Teensy 3.2 board to the Cali standalone on MAC.

    I have been struggling. My controller has simple 5 switches to on/off various effects. It works (Mainstage, Ableton, Logic etc) on "assign" etc. The same does not work with NDSP whether I try the learn more of even by assigning values

    Code snippet - usbMIDI.sendControlChange(cc0,effectOn[0],midiChannel);

    I have
    #include <OneButton.h>

    the board is in Serial+MIDI mode.

    I need help.

    Quote Originally Posted by Sedition View Post
    Hi all,

    First post here. I'm considering building a MIDI controller to control a guitar amp modeler from Neural DSP, the 'Cali' model. According to my research, Teensy is preferable to Arduino here, because of native USB MIDI, if I've read correctly.

    Click image for larger version. 

Name:	fortin-cali-cover.jpg 
Views:	14 
Size:	91.5 KB 
ID:	20530

    I'll be building an actual box as close to identical as I can to this, including the same switches and knobs. Additionally, I may also build replicas of the 3 stomp boxes featured on the other tab in the program, but that is for further down the track. I'm planning to use this in practice and gig situations, so I will likely install my Focusrite Interface in the enclosure for going direct to a PA. Another idea is to build a matching 4 x 12 cabinet with power amp and speakers, so that I could plug into a cab for practice and onstage monitoring. These are all 'further down the line' ideas like the stompboxes.

    Question 1: the Bass knob is a push-pull pot, push in for Bass, pull out for Saturation. Can this type of potentiometer be used as a MIDI controller?

    Question 2: the 4 smaller switches (Thump/Hair/Violence/Bright) are all 3 way switches, but in the MIDI control page of the app, there is only one MIDI command - actually 3, one command each for the Clean, OD1, and OD2 channels on the amp. Unfortunately, even if MIDI can use a 3 way switch, it doesn't appear that I could use that to mimic the 3 different sounds each switch gives. So, it seems the simplest option would be a momentary switch to cycle between the 3 switch stages. Would that be the obvious way to handle this situation?

    Question 3: As above, there are 3 channels in this amp - Clean, OD1, OD2 - and a full set of MIDI commands for each, ie. Clean Bass / OD1 Bass / OD2 Bass. Is it possible to use a 3 way switch to change the MIDI controller between sending Clean, OD1 and OD2 commands?

    Question 4: If I've researched correctly, one benefit of Teensy over Arduino is native USB MIDI - am I correct in thinking that the end product will plug in and be treated like a commercial MIDI controller, without having to use the additional applications I've seen required for Arduino? I can't remember the names, but I've watched videos on Arduino controllers that needed 2 different applications to work..

    Question 5: I'm not sure if this is answerable without seeing the software and manual, but would it likely be possible for the Neural software to read the positions of the knobs when it is connected, and update the software amp's knobs to the current values on the MIDI controller's pots/switches? Perhaps some code that sends a message with all pot/switch positions on repeat?

    I appreciate any responses here, and if there's something I've missed, please feel free to let me know. Apologies for the long winded explanation, I tend to over-explain things.

    Edit: I will most likely also add some controls in the back of the amp to control the top section of the software - Input, Gate, Preset forward/back, Output.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •