David wrote:

You're adding logarithms. no?

http://www.rane.com/par-a.html

Not really. It shows that intensity effect percieved pitch and that
when
adding equal non reinforcing tones the results depart from what would
be expected.

What, to me at least, makes this even more interesting is the date the
research was published, Jan 1935.

In 1974 at college I took a course on the physics of music and musical
instruments. The course ignored the whole louder sounds sharp, softer
sounds flat issue.

Terry