A subharmonic is a component of a periodic wave which has a frequency lower than the declared fundamental. As an example, a component with half the frequency of the fundamental would be the second subharmonic, and whereas the harmonic series are defined by the arithmetic multiplication of the fundamental frequency, subharmonics involve the arithmetic division of the fundamental frequency. Subharmonics can be generated by using special playing techniques in a few musical instruments (such as overblowing on some wind instruments), but are more often created artificially, if required.

A transient is a short-duration non-tonal, non-periodic sound element, usually of high amplitude and typically comprising high-frequency components. In the case of sounds generated by musical instruments, transients inherently present at the beginning of tonal waveforms are often critical to the instrument's aural signature and recognition. Transients can also be caused by a variety of fault conditions, such as incorrect clocking in digital systems.