Guy here, who programmed the C++ implementation of Operator: It was a pleasure to build the instrument together with Robert, and I learned a ton from him.<p>In the 2009 upgrade I replaced the aliasing wavetables with bandlimited ones, generated using IFFT, one per octave. With 2x oversampling, it became aliasing-free as long as you didn’t use FM. When adding the IFFT, the feature of drawing harmonics also became obvious.<p>Fun fact: The four oscillators were calculated in parallel using SSE intrinsics. It’s the only time I’ve ever been able to improve the performance of something using that particular technology.<p>For me personally, Operator is a pinnacle of my engineering career - It is one of the most-used synthesizers in the world, though of course, there are much better ones out there.