The appearance of FS/Partial is deeply related to spectograms. The graphical propositions embodied by these representations are the core for the shape and mechanics of this device.
FS/Partial has a rather strict purpose, preform additive synthesis in live contexts. Therefore, every technical feature and design option works towards a clear and inteligible solution to visually display the Fourier series.
The device provides physical control over 8 harmonic partials. The height of each tube is resposible for the amplitude of the sine it controls. From left to right, partials' frequencies get higher, the leftmost being the fundamental frequency of the produced signal.
Additional control is given through two horizontal faders located on the side of the device. One is responsible for setting the fundamental frequency , thus moving all the partials along the spectrum in equal intervals; the other, works like a low-pass filter, cutting off partials that are currently outside the interval defined by the two faders.