Prophet 6 with RIBBON controller!

[chipaudette]

Hi DSI,

I've having good success making a MIDI ribbon controller.  Like everyone else, I'm struggling with the fact that MIDI is built on the assumption of discrete notes and that continuous pitch has to be kludged via pitch bend. 

Unfortunately, the Prophet 6 tops out at pitch bend range of 12 semi-tones.  My ribbon is just the right length to cover three octaves (36 semi-tones).  Is there any changes that the pitch bend range could be increased up to at least (36/2) = 18 semitones?  If so, I can glissando my way without the ugly artifacts of switching the MIDI note number...

(Related, the NRPN section of the user manual says that the pitch bend range can be set to 24, which would be great.  Unfortunately, when I send it a value of 24, it actually only goes to 12.  Bummer.)

Any chance that the allowed pitch bend range could be increased?

Thanks!

Chip

[chipaudette]

Hi All,

I finally got my ribbon controller into a good place (though it still is unfortunate to have the pitch bend limitation discussed above).  If you're interested, you can check it out here...including a demo with the P6!

http://synthhacker.blogspot.com/2016/03/diy-midi-ribbon-controller.html

Chip

[HESpook]

On the P12 the pitch down range can be 24 while the pitch up is limited to 12. Maybe there is something similar going on here?


I assume that you have tested both up AND down but just to be sure...


It's a really sweet thing you've got there! I'd love to have one of those attached to my bass and connected to my P12. Double bass lines!

[mmpro1]

Greater PB range would also be a help to those using controllers like the Roli Rise & Linnstrument.

[Hector Space]

This is really fascinating. Good project Chipaudette! It's opened my eyes to some interesting possibilities. You've made the mechanics of adding a ribbon doable now! I'd not expected that you'd actually trigger notes from the ribbon, rather just bend them. It's cool. I particularly loved the human like voice program you demoed.
I have a Midi Solutions continuous controller to midi box. It takes a foot pedal (pot) and turns it into a midi data message of your choice! I'm just wondering how I might use this with your ribbon idea. Cool. 😎

The problem with adding extra Pitch Bend range is two fold : it pushes the overall range of the oscillators. Currently there is potentially 8octaves of notes plus a range of C1 to C5 oscillator pitch. I think if you add a further 2 octave of pitch bend youre at 15 octaves!? Clearly that doesn't work without compromise. Also the p6 pitchbend circuit has a finite mechanical/electrical/electronic resolution. Driven largely by the pot quality and ADC. The possible range of +\- 8k (14bits of data) of the midi message is probably fine but most devices don't fully encode to that resolution especially if you're using an onboard 10bit ADC, I doubt that's +\- 1bit accurate. So going beyond +\- 1 octave may produce quantised pitch steps.

As to the Roli Seaboard, I'm wondering what form of midi data message they provide for 'conventional' synths. I asked them if I could use the Roli to drive my Forte (via a USB bus master) they suggested it would work. Maybe there is away of fudging the message protocol to work more smoothly?

[mmpro1]

Roli devices can be configured for PB at +/- 12 semitones up to +/- 48 semitones. The advantage of the 4 octave range is smoother and more accurate (less quantized) pitch control. When I use my Rise 49 with my Kronos, I have to set it to +/- 12 and it works fine. But I do notice the enhanced resolution when using other synths that can respond to the larger PB settings.

[chipaudette]

The problem with adding extra Pitch Bend range is two fold : it pushes the overall range of the oscillators. Currently there is potentially 8octaves of notes plus a range of C1 to C5 oscillator pitch. I think if you add a further 2 octave of pitch bend youre at 15 octaves!? Clearly that doesn't work without compromise. Also the p6 pitchbend circuit has a finite mechanical/electrical/electronic resolution. Driven largely by the pot quality and ADC. The possible range of +\- 8k (14bits of data) of the midi message is probably fine but most devices don't fully encode to that resolution especially if you're using an onboard 10bit ADC, I doubt that's +\- 1bit accurate. So going beyond +\- 1 octave may produce quantised pitch steps.

Thanks for the thoughtful reply.  A few return comments to keep the tech talk going (I love the tech talk!)...

Regarding # of octaves: Obviously, when using my ribbon, I have no desire to go to the 15th octave, so whether the synth is able to go there (or not) won't be a problem that I would encounter.  But, you're right, the synth needs to be able to handle that case without locking up.  I have already perceived that they Prophet 6 limits the highest pitch that you can get.  I believe that if the keyboard is set to the highest Transpose setting and if the oscillator is set to the highest octave, all of the keys in the top octave play the same pitch.  So, the Prophet 6 already has a limit, and it's fine with me.

Regarding the finite resolution, I agree that the physical pitch bend wheel will likely end up sounding quantized if they enabled a +/- two octave bend.  That's not really an issue for me...I've got whatever resolution I've got (which may or may not be sufficient), but it doesn't matter whether that resolution is spread across many notes +  small bends or if it is spread across one note + big bends.  My semi-tones per bits is the same either way.  With a ribbon, I'd prefer it to be spread as one note + big bend so that I don't have to retrigger a new note in the middle of a slide, simply because I've run out of bend.

Thanks for your interest!

Chip

[chipaudette]

Based on a reply over a Muff Wiggler, I have extended the ribbon controller to do CV.  Now it'll work with my pre-MIDI synths.  If you're interested, I've got more info at the link below, including a demo with my Korg Mono/Poly:

http://synthhacker.blogspot.com/2016/04/diy-ribbon-controller-cv.html

Chip