The Pinnacle's MA-1 sampling engine uses different rates to play back
different notes. It normally plays at 48 kHZ, and can play up to 96 kHZ.
As it passes 96 kHZ, it will stop playing. Effectively at 48 kHZ, if you
go an octave up, you have doubled the frequency and also reached the end of
the range. Therefore, you will not get any sound.