supports receiving pitchbend?

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Teetswits
 
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supports receiving pitchbend?

Post by Teetswits »

Hello,

I have a simple question: does the xoxbox support receiving pitchbend via external midi?

Why I ask: I am very close to purchasing/building a unit but since I only produce music using just intonation/microtuning I need to know if the xoxbox will be compatible with toybear's microtuner plug. Cannot/not smart enough to find any clear info on the site regarding this query.

Any advice would be highly appreciated.

Peace and Love
Teetswits

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antto
 
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Re: supports receiving pitchbend?

Post by antto »

pitch-bend isn't handled in the stock firmware (thus also in none of the alternative firmware mods afaik)
it's open-source, thus you can handle any midi message you want if you recompile it
however, i think your intention is to have something like fine-tune controlled via MIDI
and that's not possible, since the cpu can only output integer note values (it's a 6-bit DAC, thus 64 possible values/notes)

you could hack it i guess, but that's probably not what you want (i'm thinking, you could use some PWM techniques with some smoothing capacitors, or modify the DAC part..)

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antto
 
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Re: supports receiving pitchbend?

Post by antto »

another alternative is, to apply the Gate/CV-IN mod (so that you can control the synth via external Gate/CV) and then use a MIDI2CV converter which supports pitch-bend
but then you'll basically leave the on-board sequencer unused

Teetswits
 
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Re: supports receiving pitchbend?

Post by Teetswits »

Hi antto, thanks for taking the time to reply.

Regrettably, since I know next to nothing about programming or synthesis, most of what you wrote went over my head!

You read my intention correctly though: my plan was to MIDI sequence in the DAW thru to the MicroTuner plug and out into the Xoxbox (not touching the Xox sequencer at all).
I believe Toybear's MicroTuner VST works by sending a finely tuned signal via MIDI to a VSTi or outboard gear. But as yet I haven't had a chance to try it on any hardware synths because I don't own anything that supports midi pitchbend messages.

antto wrote:the cpu can only output integer note values
I'm perplexed by this remark; would you mind explaining exactly what 'integer note values' are?
You see, the kind of pure harmony I trouble myself to achieve is itself based on whole number ratios:
C:1/1 D:9/8 E:5/4 F:4/3 G:3/2 A:5/3 B:15/8 C:2/1

In contrast to equal temperament which only approximates these values and produces slight dissonance nearly all of the time.

So your comment leaves me confused; does the synthesizer simply split the octave into 12 equal segments as typical 12-TET instruments do, or does it actually produce harmony based on a ratio of two integers?
antto wrote:another alternative is, to apply the Gate/CV-IN mod (so that you can control the synth via external Gate/CV) and then

use a MIDI2CV converter which supports pitch-bend
but then you'll basically leave the on-board sequencer unused
I appreciate the suggestion and I'll definitely consider this as a possible alternative, but no doubt the mod and a midi to CV converter will inflict more damage to my severely limited budget (what directs me towards a DIY synth in the first place).

I really love the sound of 303 bass and was hoping I could use it to fashion a more convenient 'live' setup.
You see, I generally begin with a fundamental frequency and then sample every relative pitch independently rebuilding the sampled instrument in Kontakt. Working this way is limiting, excludes using orthodox instruments and the time spent sampling each individual pitch is very tedious.. From my perspective at least, the resulting music is completely worth the effort, but I'm still intent on finding a more convenient and spontaneous way to create.

Teetswits

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antto
 
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Re: supports receiving pitchbend?

Post by antto »

with integer note values i meant...
to simplify it.. the cpu has 6 output pins (a DAC) where each pin can be either set high or low
those go thru a resistor network and.. blah this is not important
what's important here is that the cpu can set those 6 pins in any of the 64 possible combinations (2^6 = 64)

and the reference voltage (5.33333V) is sliced in 64, which makes the possible values be spaced out in 0.083333V steps
and 12 * 0.083333V = 1V
so that's how the pitch CV works

and this also means that the CPU cannot really fine-tune the notes

at the end, the pitch CV is converted to frequency, so to say
so i think this is equal temperament

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mmm
 
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Re: supports receiving pitchbend?

Post by mmm »

I don't think it's possible to add smooth pitchbend to the firmware since there is no point in the hardware that allows for a non-stepped control within the DAC. antto has described this pretty well.

Apart from that I doubt that it would be useful in many cases. Stock xoxboxes (with 1% tolerance resistors for R74 to R90) frequently have frequency deviations of up to 10 cent within the "normal" tempered scale. So we're dealing with an instrument here that has not exactly a very high tuning precision to begin with.

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