MOTM

Greetings,

Does anyone have the mysterious procedure for transferring custom tunings into the MOTM-650? Nothing in the manual, and only fragments of info come up on a Google search. Apparently it uses scala files, and in theory can be done, but I'd rather not stumble around in the dark if someone out there has done it and thus can share the procedure and any quirks (nobody on Muffs was able to answer, so trying this group). BTW, I'm on mac, but can borrow a PC if necessary.

Thanks,

- Solar

At 02:57 AM 5/18/2015, Solar Marquardt solar@... [motm] wrote:

>Greetings,
>
>Does anyone have the mysterious procedure for transferring custom
>tunings into the MOTM-650? Nothing in the manual, and only fragments
>of info come up on a Google search. Apparently it uses scala files,
>and in theory can be done, but I'd rather not stumble around in the
>dark if someone out there has done it and thus can share the
>procedure and any quirks (nobody on Muffs was able to answer, so
>trying this group). BTW, I'm on mac, but can borrow a PC if necessary.

I'm pretty sure all you have to do is send it a MIDI Tuning Standard
bulk dump. Several programs support it, including Scala:
http://en.wikipedia.org/wiki/MIDI_Tuning_Standard .

Jeffrey

> >dark if someone out there has done it and thus can share the
> >procedure and any quirks (nobody on Muffs was able to answer, so
> >trying this group). BTW, I'm on mac, but can borrow a PC if necessary.
> I'm pretty sure all you have to do is send it a MIDI Tuning Standard
> bulk dump. Several programs support it, including Scala:
> http://en.wikipedia.org/wiki/MIDI_Tuning_Standard .

As the author of the microtuning code in the MOTM-650, I can confirm
Jeffrey's statement 100%.

-->Neil

----------------------------------------------------------------------------
C. Neil Bradley - Excessive process falsely elevates the incapable and ties
the hands of the exceptional.

Thanks guys, I figured it out last week and posted the steps online so it shows on a Google search when someone else wants to know. Once you figure out it uses MTS, and figure out what MTS is, there's nothing to it... http://www.bendingbus.com/blog/posts/MOTM-650_Tuning_Table_Customization/

One thing I find inconsistent; say you tune to just intonation, the pitch wheel remains equal temperament semitones. If your playing style uses a lot of bends, that's a problem. Bending to some intervals will sound really bad, while others will be usable. Wouldn't it be possible for the 650 pitch wheel setting to reference the tuning table, and look up/down x number of ratios to find the correct stopping pitch?

Mentioned this to Paul last week, he says that old processor is already pushed hard, but maybe Neil would know some fancy code that could do it?

-Solar

On Jun 2, 2015, at 6:43 AM, Neil Bradley <nb@...> wrote:

>> >dark if someone out there has done it and thus can share the
>> >procedure and any quirks (nobody on Muffs was able to answer, so
>> >trying this group). BTW, I'm on mac, but can borrow a PC if necessary.
>> I'm pretty sure all you have to do is send it a MIDI Tuning Standard
>> bulk dump. Several programs support it, including Scala:
>> http://en.wikipedia.org/wiki/MIDI_Tuning_Standard .
>
> As the author of the microtuning code in the MOTM-650, I can confirm Jeffrey's statement 100%.
>
> -->Neil
>
> ----------------------------------------------------------------------------
> C. Neil Bradley - Excessive process falsely elevates the incapable and ties
> the hands of the exceptional.

> One thing I find inconsistent; say you tune to just intonation, the
> pitch wheel remains equal temperament semitones. If your playing style
> uses a lot of bends, that's a problem. Bending to some intervals will
> sound really bad, while others will be usable. Wouldn't it be possible
> for the 650 pitch wheel setting to reference the tuning table, and look
> up/down x number of ratios to find the correct stopping pitch?
>
> Mentioned this to Paul last week, he says that old processor is already
> pushed hard, but maybe Neil would know some fancy code that could do it?

Before I delve into some details, I haven't touched the code in 13 years
nor do I have any intention of doing so ever again. Further discussion may
be interesting, but ultimately just an academic exercise since there's no
possibility of a revisit.

I worked with Robert Rich on the microtuning implementation. At the time,
the topic of pitch bend with microtuning did come up. Keep in mind, this
CPU has 64K of flash, 1K of XDATA RAM, and 256 bytes of internal RAM. A
16x16 bit multiply requires slightly over 1ms of execution time. Divides
were even worse.

The issue is that it would require divides or multiplies in order to
translate linear->nonlinear DAC scaling each time the pitch bend is moved.
The entire portamento/glissando code must now understand the nonlinear
nature of glide, which means a lot more multiplies, moreso than available
compute power. Multiply that by 4 voices and it's a real problem.

The other option for getting rid of the multiplies is a step rate being
created, but that's far larger than the RAM that's available. IIRC, There
was about 30 bytes left.

I've been asked to open source the MOTM-650, which I can't do since I no
longer own the license for it (I sold the company that does) and a lot of
the code in the 650 was used in a product that's still shipping.

Paul is right. The CPU is already pushed extremely hard, especially when
the arpeggiator is running. The entire time critical codebase was written
in 8051 assembly language. It was all we could do to get it to work as
well as it did on that old CPU.

-->Neil

----------------------------------------------------------------------------
C. Neil Bradley - Excessive process falsely elevates the incapable and ties
the hands of the exceptional.