drewfx1
WallyG
drewfx1
WallyG
If I can change the position of the Super Knob with a MIDI controlled voltage, than it should be no different than changing it with your hand or the foot pedal, all things being equal.
Walt
Not quite. A 0-5V CV generated directly from a 7 bit midi CC would be divided into ~.04V steps unless there is filtering on the CV out to slew the stepping at an appropriate rate.
I understand what your saying, but if you're recording/playing back notes with MIDI and Super Knob positions with Sysex messages isn't' that the same thing? Or are saying that I would need more that 7 bit resolution? I didn't think there were 128 discrete steps of the Super Knob. I'm about 2,500 miles from my Montage (I'm in Webster, Mass), but looking at a photo of the SK on the Web there appears to be 20 discrete positions.
Walt
Sysex can have whatever resolution is required based on the number of bytes assigned to the parameter in the sysex implementation. But out of curiosity I just looked at the midi sysex implementation in the Data List manual and I found that the Super Knob position is indeed only 7 bit in this case.
So you are correct. The stepping/zipper noise is only a potential problem if the knob input has greater than 7 bit resolution. Or if they're applying smoothing/interpolation when the knob is changed but did something dumb and didn't apply that smoothing for everything that could control the knob parameter.
It's indeed very odd that it doesn't receive CC as it looks from the manual like it can be set to send CC.
Okay returned to AZ and did some further checking. The Super Knob is indeed 7 bit as you stated. I recorded just the position of the SK as I slowly moved it from left to right and looked at the Sysex data in the event list. The bit that controlled the position went from 0 to 7E (Hex).
I looked at the schematic of the Yamaha FC7 Foot pedal and it's simply a 50K ohm Potentiometer connected to a TRS Plug. One end of the pot connects to Montage ground via the shield, the other end goes a 3.3 Vdc reference via the Tip and the slider (ring) becomes the control voltage for the Super Knob position.
Thinking about it on the flight back, I believe I know why they decided to use Sysex to record/playback the SK position. The Montage can have 16 channels of "parts", each with thier own MIDI channel. Instead of assigning a MIDI CC to control the position, they used sysex to 'Isolate" that function. All well and good but there is no easy way to edit the position if say you did a world class performace on the keyboard that you cound never repeat, but the timing of the SK was off and spoiled it.
I don't envision recording 16 parts at once, so I want to have a MIDI to CV converter on a channel I'm not using, or a CC on a channel I am using. Make sense?
Walt