Fair enough Chas. I certainly agree that one has to use their ears AND know what a Leslie 122 sounds like in the first place. Personally, I love to hear a Leslie ramp up and down. If one is satisfied, as many of you are, use your internal sims and be happy, but a #57 rotor is not good enough for me. Don't get me wrong,as many people don't even know what a Leslie is and wouldn't care. In my case, I know there is a profound, not miniscule, difference using the Ventilator, as opposed to the internal sim of the Nord Electro II, G70,Kn7000, and Kurzweil KB3 section.