Spectra is a seven note synthesiser built around the natural harmonic series. Each key is physically shaped to represent the waveform of its corresponding harmonic - so the instrument can be read by touch as much as by ear, the bumps and curves of each key mirroring the complexity of the sound it produces. Moving across the keyboard is a journey up the overtone series, from the deep simplicity of the fundamental through to the increasingly dense and intricate upper partials. Spectra makes visible and tangible something that is usually hidden inside every sound.