Which Partial ?

Richard Moody remoody@midstatesd.net
Fri, 1 Nov 2002 20:00:08 -0600


>told me the oct. type (10:3, I think)  but I
> deleted the post.

It should be 10:2   if you want to use the 10th partial.  5 :1 if
you want to use the lowest partials.  Below is how it figures out.


                     Coincident partials
Octave       2:1 ,   4:2,  6:3, 8:4  10:5

Double octave    C2 -- C4    4:1

3rd                     Ab4--C5  5:4                C4  is middle
C
10th                   Ab3--C5   5:2
                          Ab3--C4--C5   5:4:2  <-notice 4:2 oct.

Double Oct      Ab2--C5      5:1
+ 3rd (17th)

 By words, the ratio of the 3rd is 5:4.  This means the 5th
partial of the lower note is close to or "coincident" with the 4th
partial of the upper note.  The numerical difference between
coincident partials gives the beat rate.    If you drop the lower
note one octave, making a 10th, its 5th partial (now an octave
lower than before) is coincident with the second partial of the
upper note.   If you drop one more octave the 5th partial and
first partial are coincident.

If you want to use the 10th partial it would be 10:2  for Ab2--C5.

For aural tuners, if the beat rate of Ab4--C5  is 12   the rate
for  Ab3--C5 will be 6.   for Ab2--C5 the rate will be 3.


----- Original Message -----
From: Jon Page <jonpage@attbi.com>
To: College and University Technicians <caut@ptg.org>
Sent: Friday, November 01, 2002 5:58 AM
Subject: Which Partial ?


> Is there a reference to show which numerical ratio (ie: 4:2)
goes with
> which partial
> and why a certain oct. type couldn't be used in a particular
register.
>
> I suppose that I could figure it out if I had the partial
sequence in front
> of me.
> I'm new to this 'tuning-by-numbers'.
>
> Primarily, I'm interested in a double octave and a third for the
low bass
> to give it
> a proportion in my VT. Ron told me the oct. type (10:3, I think)
but I
> deleted the post.
>
> Jon Page
>
>
> _______________________________________________
> caut list info: https://www.moypiano.com/resources/#archives


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