If I play a scale on the white notes going
up from middle C, the G seems noticeably
weaker than the other notes. (The F seems
just slightly weaker).

I have set all the velocities to the same,
and I have tried listening on 2 different
speakers in 2 different rooms in case my
system has a hole in the frequency response.

Has anyone else noticed this? Do the samples
need touching up?