A subharmonic synthesizer is a device or system that generates subharmonics of an input signal. The nth subharmonic of a signal of fundamental frequency F is a signal with frequency F/n. This differs from ordinary harmonics, where the nth harmonic of fundamental frequency F is a signal of frequency nF.
Subharmonic synthesizers can be used in professional audio applications as bass enhancement devices.
Other uses for subharmonic synthesizers include the application in bandwidth extension. A subharmonic synthesizer can be used to extend low frequency response due to bandwidth limitations of telephone systems.
Subharmonic synthesizers are used extensively in certain genres of music such as house, or disco. They are often implemented to enhance the lower frequencies, in an attempt to gain a "heavier" or more vibrant sound. Various harmonics can be amplified or modulated, although it is most common to boost the fundamental frequency's lower octave. The kick drum can benefit greatly from this type of processing. A subharmonic synthesizer (or "synth" as it is known in the industry) creates a bigger presence and can give the music that much sought-after "punch".