Open-Source MATLAB Tools for interpolation of SDIF sinusoidal synthesis parameters

We have implemented an open-source additive synthesizer in the matlab language that reads sinusoidal models from SDIF files and synthesizes them with a variety of methods for interpolating frequency, amplitude, and phase between frames. Interpolation techniques currently implemented include linear frequency and amplitude ignoring all but initial phase, dB scale amplitude interpolation, stair-step, and cubic polynomial phase interpolation. A plug-in architecture separates the common handling of SDIF, births and deaths of partials, etc., from the specifics of each interpolation technique, making it easy to add more interpolation techniques as well as increasing code clarity and pedagogical value. We ran all synthesis interpolation techniques on a collection of 107 SDIF files and briefly discuss the perceptual differences among the techniques for various cases.