This is a reissuing of bug 1476, originally issued against SB1s as a hardware problem. 1476 was closed won'tfix because the underlying hardware problem is a limitation of the hardware and could not be fixed. 

At that time, I asked if the code which limits mixer pitch commands could be changed to implement the actual hardware limits.

I recently discovered that the same line of code still exists in 6.

I believe the line to fix is in Squeezebox.pm.

sub maxPitch { return 120; }
should read
sub maxPitch { return 110; }