Reply To: 88-key MIDI keyboard + modular CVs

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tubbutec wrote:
SlyFrank wrote:
If I set Middle Note to 3V, then the lowest 2 octaves of my sequencer (0-5V) don’t respond, and I only get a 3-octave range. I understand why, now, after studying this and playing around with it.
Setting the middle note to C5 / 60 and middle voltage to 3V will result in the µTune’s output reaching 0V when playing C2 (assuming 12notes/octave). Anything lower will be capped to 0V.

Took me a while to understand your setup completely and figure out the problem. I believe the core of the problem is this:

via CV you get inputs from 0-5V, which maps to note numbers 0..60
via midi you get inputs in a different range, but essentially you want to press the lowest keyboard key and get note number 0 and press the middle C and get note number 60. Correct?
Which are the note numbers you are receiving in µTune when pressing these keys?
After writing the below, I figured out part of the problem. It is with my Cwejman VCO-6s, which I use mostly. They are limited by the range switch such that to get to the lowest bass notes that are typical for any VCO, one has to send note CVs in the range of 0V…2V. That is normal behavior, but as you read below you will see why I am having a bit of an issue (this is nothing major, just trying to figure out the best way to work). I have a few other VCOs, and they can be tuned quite a bit lower than the Cwejmans (no range switch limitations) such that they overcome the 2V minimum issue from the MIDI keyboard. My DPO can almost be tuned low enough – it ends up about one semitone too sharp, though. Braids has no problem and can be tuned so low that even outputting 2 – 3 V from the uTune gives great bass notes. My solution to this problem might mean that I only play my MIDI keyboard through my synth using Braids, or use the offset solution. Anyway:

Hi – yes, essentially you understand my setup, except that what I am trying to achieve with my lowest MIDI keyboard C is an output of 0V, not necessarily a note number of 0 (whatever the note is called I don’t really care, just want it to be at 0V which then makes Middle C = 3V. 60 C5 is the Middle note set in Keyboard Mapping in uTune, which is my Middle C. So actually my lowest C is outputting C2 & and Middle C is C5 & Note 60). I agree that by putting MIDI note 60 at 3V means that the CVs from 0V…2V will all be read as C0 or output 0V until it gets to above 2V (2V output actually = 0V since middle note 60 is set to 3V). Once I change MIDI note 60 back to 5V then my CV sequencer works perfectly. All CVs from 0V…5V output the proper quantized notes. This makes perfect sense.

The issue is that on my MIDI keyboard, it is as you say, if I would like MIDI note 60 to sound as Middle C, and to have the lowest C on the keyboard output 0V, then I can only do that by making MIDI note 60 = 3V, which of course then screws up my CV sequencer. If I set middle note 60 = 5V then my sequencer works fine but the lowest C on my MIDI keyboard = 2V, which is 2 octaves too high (for a Cwejman VCO-6, since it can’t be tuned low enough to compensate for 2V+ input – it needs to ‘see’ 0 – 2 V).

My workaround is to either send a -2V offset to the VCO6(s) connected to the keyboard’s output (coming through uTune, with middle note set to 5V) or to send a +2V offset to my CV sequencer’s output, before it enters the uTune, which is set to middle note = 3V. So I can send an offset, which works…but that’s kind of a pain and is clunky. And working with many VCOs can be sometimes hard to work with sending multiple (not just one) voltage offsets.

So I was just wondering if there is a setting that would solve this, or do I just keep working with it this way? I don’t really see any other way, but thought I would ask. No major problem, I can work around it, just wondering if I’m missing an easier solution.

OK, thanks for any input!