In the treble section of almost every upright piano false beats are stronger in the left strings than in the right strings of the unisons. Any idea how come?

Gregor

I haven't noticed that.

Examine the bridge notching to see if there is some systematic error causing the left front bridge pin to be poorly-supported.

Robert Scott
Ypsilanti, Michigan

I have definitely noticed this. On some pianos I tune octaves right string to right string in the treble because of this. I can only guess that it has something to do with the left bridge pin being on the corner of the notching. I think it was mostly on cheaper, older, consoles and spinets. I haven’t noticed anything different in the notching, but I am no expert. I have also tried tapping bridge pins and seating the strings, but it only helped a little.

I've noticed this rather more often on either outside string rather than the center. I was once told that if the hammer has a little play because the bushing is worn and if the strings aren't parallel to the hammers face the transverse wave produced on impact can veer off from the direction of the hammer swing when the hammer strikes and rebounds. If the termination point is not equal because of poor notching or seating of the string, the combination of these factors lend to louder false beating on the outside strings.

Nope. The shop where I made my apprenticeship sold Bechstein. Even on brand new Bechsteins that effect was audible. Coincidental the owner of that shop was Karl Schulze from Bechstein. We asked him how come and he could not answer. His answer was more like: either one can tune (and eliminate false beats) or one can not tune. Somewhat unsatisfying, but he was the boss

Gregor

Reminds me of "The Emperor's New Clothes!"