Tocante frequency measurements

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pugix
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Tocante frequency measurements

Post by pugix » Sat Feb 21, 2015 12:44 pm

I measured the 24 frequencies on my Bistab in Hertz.

Method:

Since the meter would not lock onto the output of the Tocante (buffered through a mixer), I measured the square wave of a music VCO with my Fluke 115 DVM. At the same time the VCO was mixed with the Tocante output and fine tuned to eliminate the beat frequency by ear. These results are at least accurate to three digits. Has anybody else done this?

90.9
95.2
108.0
134.5
145.0
156.8

197.5
218.9
225.2
297.0
317.5
339.0

446.6 -- Very close to the next one. Nice 3 Hz beat frequency.
449.5
497.0
654.0
684.0
728.5

928.5
1000
1111
1400
1472
1574
Richard
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Post by pugix » Sat Feb 21, 2015 4:48 pm

Noticed something of interest. Starting at 108 Hz, every third step we find six approximate octave intervals.

108 - 219
157 - 317
225 - 449
339 - 684
497 - 1000
728 - 1472

These are probably due to the capacitor choices and inexact, due to tolerances.

So it's likely that each individual Tocante has slightly different tunings, and perhaps the three kinds of Tocante have different intervals as well. Should make it interesting to play multiple Tocantes together.
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Post by VortexRanger » Sat Feb 21, 2015 7:54 pm

Tocante wrote:What is the scale?

Technically it is a segment of the undertone series consisting of the following degrees: 165, 150, 136, 110, 100, 94, 75, 68, 66, 50, 47, 44, 34, 33, 30, 23.5, 22, 20, 15.5, 15, 13.6, 11, 10, and 9.4. Clusters of three use a simple law of parallel and series capacitors to achieve octaves that fill in other scale values. The tuning also involves precision factors for the components, making each instrument unique.
That is from the Tocante FAQ: http://synthmall.com/tocante/faq.html

I used those ratios to create a roughly identical tuning on my Shnth (attached). If each instrument is unique, then the deno of the horn will probably have to be altered for each (short 26 80 worked best for me). Also I did not yet deal with exactness in the beat frequencies, which could potentially be found by using "short" on more values. I needed to use "arab" in order to get the highest numbers to work.

The togo is stepped back and forth through by the first major and minor buttons. This is not really a usable patch, more just a template for building actual sitches on to be used with Tocante. Mine, by the way, is a Phashi.

;bb
{(arab (togoc (major )(minor )(short 9 51 )10 11 (short 13 77 )15 (short 15 64 )
20 22 (short 23 64 )30 33 34
44 47 50 66 68 75 94 100 110 136 150 165 )
(left (right (modo (hornc (togoc )(short 26 80 ))4 ))))
}
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Post by pugix » Sun Feb 22, 2015 8:26 am

I must have seen those in the FAQ. Thanks for pointing it out. Now I have to ponder how those numbers result in the frequencies I measured.
Richard
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Post by VortexRanger » Sun Feb 22, 2015 8:55 am

I'm pretty sure they are ratios that do hold up when measured in Hz. I notice that if you multiply any of the "degrees" from PB's list by 9.5 or 10, you get a number that is close to the corresponding frequency measured by pugix.

What I don't know is exactly what the ratios are in reference to. It says they are derived from the undertone series, which I think is like the inverse of harmonics - every second oscillation, third oscillation etc. making me think that the reference point, 1, should be ten times higher frequency than the second highest note on the Tocante instruments (whose "degree" is listed as 10): ~14720 according to pugix's observation. This is not quite a "supersonic" frequency, which kind of confounds the initial thought I had on seeing "undertone series" that maybe these ratios were based on beat frequencies of supersonic tones as in a theremin etc.
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Post by VortexRanger » Mon Feb 23, 2015 7:11 am

Haha, actually I am totally wrong about this, because 10 is not second from the top, it's second from the bottom.
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Post by bubbleandsquawk » Fri Oct 05, 2018 8:07 pm

Has anyone had a go at creating a scala file for the tocante scale?

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