[Fwd: [Fwd: a Question from Terry Riley]]

I forwarded Terry Riley's question on to Steve Curtin, the fellow who wrote
most of the MR-series' MIDI Tuning Standard code. This reply probably doesn't
say a whole lot more than we already know, but perhaps a little!



Steven Curtin wrote:

> I'm honored to be able to help. The name of the guy who wrote MIDI Tuning
> Wrench is Jim Johnson, he's on the synth-DIY mailing list. That's odd but
> not unexpected that the Unisyn stuff doesn't work, since they laid off the
> guy who maintains it about six months ago :(.
>
> Contact info for Jim Johnson:
>
> Jim Johnson
> Metaphoric Software
> -------------------
> Makers of Techno Toys
> Software for Electronic Music
> http://www.technotoys.com
> info@technotoys.com
>
> You should also mention to Terry and David that I have Forth code that can
> change the tuning of the MR. I used this code to test the MTS
> implemetation in the MR. He could have someone build a little standalone
> tuning controller based on the New Micros 68HC11 microcontroller or
> something similar.

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End of TUNING Digest 1480
*************************

Thanks for all the response to my overtone/tone color question. So does it
follow that ideally one takes into consideration the natural acoustic
properties of a particular instrument when one is choosing a particular tuning
system for an instrument? Can anyone offer a good example where the complex
vibrations and shape of a particular instrument are highly integrated with the
system of tuning?

> Are overtones different frequencies
> produced by different aspects of whatever materials are producing the sound?

The materials vibrating a significant factor, but the most important factor
is the shapes and available kinds of movements possible in that configuration.
The most important thing about a string, for example, is that its diameter is
only a tiny fraction of its length, that it is anchored firmly at both fret and
bridge ends, and that it is made of a flexible material.

This is what allows it to vibrate at very nearly precisely-harmonic
frequencies. What makes those frequencies not completely harmonic are the
departures from this idealized model of a string, such as the fact that high
piano strings' are so short and thick, and under such high tension, that they
are no longer a close approximation to being arbitrarily flexible and infinitely
longer than their diameter.

As another example, the most acoustically-significant difference between a
clarinet and a saxophone is that the saxophone's bore is conical, meaning that
the diameter of the tube is much narrower at the mouthpiece end than at the bell
end. Except for the bell at the end of the horn (which has a lot less
acoustical significance than it would initially seem), the clarinet's bore is
much closer to cylindrical (i.e., nearly equal diameter throughout).

The combination of a cylindrical bore and a reed produces stronger
odd-numbered harmonics than even ones, whereas, a saxophone (as well as other
conical-bored instruments like the oboe, bassoon, or most brasses), have about
the same prominence of even and odd harmonics.

Now in the case of wind instruments, it's very critical to understand what
the "materials" are. What vibrates in a wind instrument is the air inside the
tube. The walls of the instrument itself vibrate only slightly, except in a
mere handful of specific cases (quadruple-forte, unstopped F.horn, for
example). That is obviously completely the opposite for a stringed instrument -
the soundboard is the entire means of transferring the sound generated by the
strings to the air, so the soundboard imparts its vibrational qualities to the
sound of the instrument.

That is NOT to say that the material a wind instrument is made of has
absolutely NO effect upon its timbre, but that is a much less significant factor
than its forcing means (e.g., reed, edge, lip-buzzing) and its bore geometry.
No matter what material you make a flute out of, it's always going to sound more
like a traditional flute than like a bassoon.

Nangaku@aol.com wrote:

> Thanks for all the response to my overtone/tone color question. So does it
> follow that ideally one takes into consideration the natural acoustic
> properties of a particular instrument when one is choosing a particular tuning
> system for an instrument?

The relationships between timbre and tuning are exactly the topic of Bill
Sethares' recently-published (by Springer) book/demo CD, "Tuning Timbre Spectrum
Scale". Interesting book.

> Can anyone offer a good example where the complex
> vibrations and shape of a particular instrument are highly integrated with the
> system of tuning?

It would not be difficult to imagine that a timbre like a clarinet's, having
weak even harmonics, would be more "picky" about the precision of a 5:3 major
sixth than of, say, a 3:2 octave. That since it has strong 5th and 3rd harmonics
that could beat against each other if not tuned precisely, whereas its second
harmonic could be weak enough to not be as picky about that.