Tunelab question?

[Jim Coleman, Sr.]

Hi Brian:

The purpose of the saw tooth curves is due to the change of partials used
in the tuning curve. You will notice that from A4 on up where the tuning
is all done by the 1st partial, the tuning curve is smooth. This same 
thing is true of the RCT curves or the SAT III curves. These saw tooth
curves contribute to the smooth tuning of the pianos. If you think they
are giving you an irregular tuning, you might do well to recheck how well
you have stopped the patterns for the affected notes.

Jim Coleman, Sr.


On Fri, 28 Jan 2000, Brian Trout wrote:

> Hi List,
> 
> Those of you who have seen Tunelab will likely know what I'm talking about.
> I'm not sure if RCT is similar.
> 
> When I measure the inharmonicity of the 5 or so notes I need to use the
> Calcul8 program, and hit "Calculate", it produces what the mathematics
> consider to be a good tuning.  (Sometimes it's better than others.)  I am in
> the habit of going to the graphic tuning editor immediately after using the
> calculate function just to get an idea of what it has done, and see if I
> want to do a bit of tweaking.
> 
> What I noticed is that instead of a smooth sort of "S" shaped curve like one
> might anticipate, it looks more like a modified "saw tooth wave".  I had
> noticed in an advertisement for one of the new Peterson tuners a graphic
> representation of a tuning and did notice a very smooth curve, not the "saw
> tooth type" that the Tunelab tends to produce.
> 
> I have noticed on occasion that the beat intervals are not always as even as
> I would try to make them if I was tuning strictly aurally, and I have
> suspected that the way in which the tuning "curve" is calculated, using
> these "modified saw tooth wave patterns",  might explain the variations in
> beat rates.
> 
> Does anyone have any ideas of why the tuning curves are calculated that way?
> I'm guessing there is a very good reason.  I just don't know exactly what it
> is.
> 
> Jim C.?  Rob S.?  Dave P.?
> 
> Not meaning to be critical.  Inquiring minds just want to know.  <grin>
> 
> Have a nice weekend, all.
> 
> Brian Trout
> Quarryville, PA
> btrout@desupernet.net
> 
> 
>