Octave Tuning

[Jenneetah]

At 6:43 PM -0700 9/28/04, Matthew Todd wrote:
>When I tune the temperament octave (A3-A4), it needs to be a 4:2 
>octave, correct?

For your purposes, just to get you on your way, yes. However, my 
temperament octave is 6:3 (until in the vertical range, the piano 
drops below 45", then it's a balance between the 6:3 and 4:2). 
Bernhard Stopper and Ric Brekne have detailed temperament compasses 
of the P12. I recently worked this out acoustically, not being one to 
calculate temperaments in a spreadsheet and pass the offsets over to 
an ETD.

>And one way to test this octave is to play the A two octaves above 
>the lower note as the test key, to hear the partials in the octave, 
>am I right?

If the test key is F2 and your temperament octave is A3-A4, yes.

>If the octave you are testing has no beat whatsoever, you have a 
>perfect temperament octave, is this true?

If your "perfect temperament octave is defined as the 4:22 on A3-A4, 
yes. Listen closely to A3-A4, and you pick up other octave 
relationships besides the 4:2 you've chosen to work with. Like the 
2:1, the 6:3, the 8:4, each with their own octave test.

What a complicated web we weave, when first we practise to tune a piano.