The creation of complex waveforms by adding together component sine waves; the inverse (conceptually) of a Fourier transform. Additive synthesis can theoretically produce any possible waveform, but in practice it is difficult to design and work with. Additive synthesis is impractical to implement with analog circuitry; it can be performed digitally but the amount of computing power needed is considerable.In the past, only those with access to large mainframe computer installations could experiment with additive synthesis. In the late-'70s, the Synergy digital synthesizer brought additive synthesis to the upper-end keyboard market, but it never really caught on commercially.Only a few other mass-market synths have been produced since which support additive synthesis, the best known of which are the Kawai K5 and K5000 series. However, as the processing power of personal computers has improved, additive synthesis is making a comeback in the form of soft synths and plug-ins.