Russ,

You are partially correct. Think of the Doppler effect as you would a train going by as it blows it's whistle. As the train approaches, and goes past you, and further away, the frequency of the sound changes. A Leslie does do Doppler but unlike the train it throws the sound all over the room as a bonus. The Doppler is only the frequency shift as the sound approaches and departs.

Also as the Leslie horn faces you and goes away there is also a change in amplitude "loud and soft".

To sum it up a Leslie gives us three different effects:

Amplitude modulation ie. loud and softs
Frequency modulation ie. Doppler effect
and sound dispersion ie. throwing the sound all over the room

Tom

PS. Russ, if you had your masters degree from a good northern college (Michigan or Michigan State)instead of some second rate hillbilly college you would have known these things. (;