octave test?

[Jim Coleman, Sr.]

Hi John:

The slow beat comes from the 2:1 and 4:2 relationships of the Octave you
are checking.

Jim Coleman, Sr.

On Sun, 18 Apr 1999, John M. Formsma wrote:

> Greetings List,
> 
> Last night I was tuning my mother's 1922 Bechstein grand for practice, and
> noticed something while doing the M3-M10 test to check octaves up from the
> temp octave. While I can hear if the M10 beats faster or slower than the M3,
> when all three are played together, there is a much slower beat that can be
> heard besides the faster third/tenth beats. This can be "tuned out" so that
> no slower beats are heard while all three are played together.
> 
> Since I am basically a beginner in aural tuning, is this useful for
> anything? For an example, if you are tuning E5 to E4, checking for equal
> beats with C4, play all three together. If all are in tune, there will be no
> audible beats other than the third/tenth beats, which will be rather fast.
> Otherwise, if C4-E5 beats a little faster/slower than C4-E4, there will be a
> slow beat when C4-E4-E5 are played together.
> 
> I realize this shows only that the E4-E5 octave is in tune, which can be
> accomplished by playing the M3 and M10 separately. But are the three notes
> played together useful as a test, or do I merely qualify now to be called
> Mr. MOTO (Master of the Obvious)? <grin>
> 
> John Formsma
> 
> P.S. I have been scratching around on a piece of paper, wondering which
> partials would cause the slow beat. Is it the 5th partial of C4, the 4th
> partial of E4, and the 2nd partial of E5? Just curious...
>