A team of scientists are trying to discover why violinist Mari Kimura is able to play the sounds she does-sounds, they claim, are supposed to be impossible to produce on a violin. Kimura even demonstrated the sounds to top US scientists, but left them stumped as to how she was doing it. To explain why these sounds are astounding:
Stringed instruments work by having a string being vibrated. The
string is shortened or lengthened using the fingers. The shorter the
string, the higher the pitch and vice-versa. Normally, you would not
be able to make a pitch lower than the lowest note on an instrument
because you can only shorten the string, not lengthen it. The sounds
that Mari produces are of a pitch that requires a string longer than
the strings on the violin.
Kimura-san’s site has examples of the subharmonic sounds, if you’re interested.