For consideration, to add to the effects available in Pianoteq, a rotary effect (amplitude and frequency modulation combined), like the famous Leslie cabinets for Hammond organ, with a widget in the Pianoteq Effects editor to control the speed of the rotation effect, as well as MIDI mappable settings for slow and fast horn and drum rotation (Leslie's "chorale" and "tremolo" settings) either combined, or (would be nice) the speed and direction of rotation (audible in a stereo or multi-speaker field) independently settable (and independently MIDI mappable) for the higher-frequencies' double-horn speaker and the lower frequency speaker's rotating drum.
From Wikipedia--
https://en.wikipedia.org/wiki/Leslie_speaker
The Leslie is specifically designed, via reproduction of the Doppler effect, to alter or modify sound. As the sound source is rotated around a specific pivot point, it produces tremolo (the modulation of amplitude) and a variation in pitch. This produces a sequence of frequency modulated sidebands.
--
]]>