Temperament Setting Question

[Jim Coleman, Sr.]

Hi Jerry:

If you have my notes on setting the Baldassin/Sanderson/Kimbell/Tremper
Temperament, your will notice that I deliberately set the first F3-A3
at 8 or 9 bps instead of 7bps. Then I tune the F4 octave just the same
as the A3-A4 octave. The purpose for this (a Rick Baldassin idea) is
that all three M3rds (F-A, A-C#, and C#-F) will be about the same and
it will be easier to fit the C#4 exactly so that the middle M3rd is
the same or equally between the other two 3rds in speed. After this,
I next tune the F4 so that the middle 3rd C#-F4 is equally balanced
between the two A's. As a result the 3 contiguous 3rds from A to A
will each be in a 5:4 ratio (relationship?). After this I tune the
F3-A3 to balance with the other 3 M3rds and also check the F3-F4 octave.
The result of this may not make the F3 M3rd equal 7 bps, but it will
be the speed which this particular piano requires. Pianos which have
a hockey-stick shaped Tenor bridge will usually have a slower F3-A3
M3rd. Only large pianos with low inharmonicity will actually have
a 7 bps speed on F3-A3.

Jim Coleman, Sr.


On Thu, 16 Dec 1999, Jerry Hunt wrote:

> I understand and appreciate the extent to which
> setting the contiguous thirds F-A, A-C#, C#-F & F-A in
> a 4:5 ration sets the foundation of a good temperament
> (of the ET variety). Most of the bearing plans I've
> seen start with something like "set F3 to A3 to beat
> about 7bps, set C#4 to A3 to beat about 9bps, tune F4,
> test that the contiguous 3rds have a 4:5 ratio..."
> 
> My question is this, having tuned the F's and the C#
> and noting that the ratios aren't working out quite
> right, how do I determine if the problem is the F's or
> the C#?
> 
> Many thanks for your help.
> 
> Jerry Hunt
> Associate Member PTG (shooting for RPT in 2000)
> Dallas, TX
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