Effects units are and remain popular, especially with pop musicians. These units, phasers, clippers, flangers, and so on are used to make a specific sound or range of sounds. This article describes how such an effects unit may be built from simple means. It is another application of the pitch shifting technique as used in phasing, chorus and flanging, but, unlike true pitch shifting in which a constant interval is created above or below the input signal, it shifts a specific audio band.It has been said before, and will no doubt be said again many times: we live in a funny world. Most music lovers go out of their way and are prepared to spend a lot of money to achieve music reproduction with as little distortion as possible.There are, however, others (lovers of a different type of music) who go to great lengths to get away from high fidelity sound. These people feel that the sound processing must match their ideas of what music should be.