RPT test, top octave, was Re: Aural Octaves

[Kent Swafford]

On Tuesday, February 4, 2003, at 12:11  PM, Charles Neuman wrote:

> What it says about the top octave is: "For purposes of this 
> examination,
> do not stretch the high treble notes more than is necessary to get good
> clean sounding octaves all the way to the top."
>
> Does that really mean "2:1 octaves need to be beatless in the top 
> octave"?
> I think in the class we were told something like, "Don't stretch it as
> much as you might like."

"Clean-sounding" does not mean exactly the same thing as "beatless".

General instructions for stretching will sometimes say, "Tune the 
octave so that it is both stretched and still clean-sounding." In other 
words, make the tests measure the octave as stretched, for example, the 
10th faster than the 3rd in the M3rd-M10th test of the 4:2 octave, but 
when you play the octave, the overall effect should still be clean, 
with no obvious beating. There is a certain elasticity in octave-tuning 
because the various coincident partials in a given octave will go 
beatless in different places; for example, if the 2:1 is exactly 
beatless, making the 4:2 narrow (depends on the location in the scale), 
it is better to introduce some stretch (on the wide side) to get the 
best overall clean-sounding effect. This is one of the reasons that 
stretching is done, to get the most pleasing overall sound from the 
composite effect of the various partial relationships present in an 
octave. I digress.

The RPT tuning exam calls for clean sounding octaves in the high 
treble, read that as clean _single_ octaves. This is simply for 
consistency so that the reference tuning can be agreed upon in the 
master tuning session, and so the exam can be scored fairly. On some 
pianos, if you tune clean _double_ octaves or clean _triple_ octaves 
the single octaves will go way wide. However, the variation from piano 
to piano of the effect varies so greatly, for simplicity's sake they 
decided to specify "clean-sounding" single octaves in the top octave. 
It was arbitrary. I kind of wonder if the exam were being put together 
today, if they might not specify clean-sounding _double_ octaves. But I 
digress again.

The tolerances in the scoring of the top octave are such that the 
examinee needn't worry _too_ much about getting exactly the right 
amount stretch. I would be careful not to tune the top treble notes on 
the narrow side of 2:1 octaves but a little stretch beyond pure 2:1 
octaves (a couple cents worth) is _very_ unlikely to hurt your score.

Kent Swafford