4th tests

[Alan Barnard]

Play the lower note with the major third below it, compare to the 6th
between the upper note of the 4th and the test note. The sixth MUST be
faster or you are on the wrong side, i.e., you're 4th is narrow instead of
wide. Example: Test the A3-D4 4th with F3, the F3-D4 6th must beat faster
than the F3-A3 third.

If the beat of the fourth is hard to sort out from false beat in the
string, try playing the fourth more softly, while listening hard. Or, in
the tenor and bass, you can play the ghost tone by holding down the fourth
and striking, then releasing, the note two octaves above the lower note of
the fourth, e.g., ghost the D3-G3 fourth by holding it down and wanging
(and releasing) D5.

The only other tests I know of are comparing it's beat rate with other 4ths
you've tuned (once you're sure the interval is properly on the wide side of
pure) and comparing your fourth to it's companion 5th in a good, clean,
pure to slightly wide octave. The fourth must beat faster than the fifth,
usually about 1 bps or slightly faster if you are brave and like purer
fifths, e.g., in the D3-D4 octave, the D3-G3 4th is appreciably faster than
the G3-D4 5th.

Alan Barnard
Salem, Missouri


> [Original Message]
> From: Giovanni Voltaggio <a440ps@sbcglobal.net>
> To: Pianotech <pianotech@ptg.org>
> Date: 09/29/2005 2:58:04 PM
> Subject: 4th tests
>
> Hi List -
>
> I was trying to remember the tests for P4ths but I can't recall  
> those.  On a piano with nice clean beats setting a P4th isn't much of  
> a problem, but test intervals can sometime make the process easier.
>
> Giovanni V. 
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