The static frequencies are modeled as the weighted
mean of the frequency for the sustain part of each
partial, denoted ˆ f k
.
Most sustained instruments are supposed to be
perfectly harmonic, i.e. ˆ f k = k
ˆ f 0
. The frequencies are
therefore best visualized divided by the harmonic
partial index. The piano, in contrast, has inharmonic
partial frequencies due to the stiffness of the strings
[26]. Therefore, the piano partial frequencies are
slightly higher than the harmonic frequencies.