Coyote Centrifuge is a DirectX (DXi) plugin that offers professional-quality rotating speaker emulation effects.
The plugin models many aspects of a variety of mechanical rotating speaker systems, including separate bass and treble channels, each with individual control of fast and slow speeds, and ramp time.
Good Points
Realistic emulation of vintage rotating speakers (eg. Leslie (TM)). Lots of control over all aspects of the effects.