> The > width of the central peak ... increases as > the interval decreases, but I could not come up with any simple mechanism > that would shift the maximum of the curve noticeably.
I verified this experimentally. In other words, determining frequencies with shorter time intervals in Fourier analysis is like reading a speedometer whose needle get wider -- you're OK if you use the middle of the needle as the "hotspot". > Maybe the following qualitative argument explains your observed shift to > lower frequencies. Initially, all the vibrational energy is in the vibrating > string. Then other parts of the lute start to vibrate too, which means that > the the body of the lute drains energy out of the string, which provides an > effective damping mechanism. If we can consider the vibrating string as a > damped harmonic oscillator, it would indeed vibrate at a lower frequency than > an undamped string. I find this plausible. We might even cast other harmonics within the same string as dampers (or even antidampers), since energy transfers between the harmonics due to string "imperfections" such as stiffness and finite stretchability. To get on or off this list see list information at http://www.cs.dartmouth.edu/~wbc/lute-admin/index.html
