An overtone is a natural resonance or vibration frequency of a system. Systems described by overtones are often sound systems, for example, blown pipes or plucked strings. If such a system is excited, a number of sound frequencies may be produced. These frequencies, are usually, but not always, a close approximation to an integer multiple of a lowest resonance frequency. Thus, overtones and harmonics shouldn't be confused or interchanged. By definition a harmonic is an exact integer multiple of… (More on Overtones)