Talking further about musical instruments and "one-tenth wavelength" rule:

- The hammers in the grand piano are placed to hit the strings at about 1/7 from one end.
- A violinist or cellist bows the string at around 1/10-1/7 from the bridge (in fact, the louder he wants it the closer to the bridge he bows).
- Organs have the reeds placed at about 1/8 from the bottom of each pipe.

[incidentally, in all cases the string/air-column lengths represent a half wavelengths]