Entries found for search: harmonic

**anharmonic** : See *="index.php?search=1&searchtxt=inharmonic">inharmonic*.
**aharmonic** : See *inharmonic*.

**harmonic** : A frequency that is a whole-number multiple of the *fundamental*. For example, if the fundamental frequency of the sound is 440Hz, then the first two harmonics are 880Hz and 1.32kHz. A harmonic is the same as a *partial* where the partials exhibit the property that the *overtones* are mathematical multiples of the fundamental frequency. See *harmonic series*, Appendix C.

**harmonic distortion** : The onset of harmonic distortion is the displacement of energy from a single frequency to its *harmonics*. The presence of harmonic frequencies added to an output signal by an electrical circuit or speaker, generally undesirable, caused by the system not being perfectly *linear*, such as when an amplifier is operated in a nonlinear portion of its *transfer curve*. It is expressed as a percentage of the original signal:

__ (Total Signal - Fundamental Signal) __ THD = Total Signal In a perfect audio device, such as an amplifier or tape recorder, the output signal would be a replica of the input signal with no changes except possibly the amplitude of the signalmaybe power level. See also *doubling*.

**harmonic enhancement** : A technique used by *aural enhancers*. See *harmonic synthesis*."

**harmonic envelope** : The natural *decay* in the *harmonics* of a natural instrument over time.

**harmonic series** : A set of all of the frequencies which are an integral multiple of the frequency of the lowest tone, or *fundamental*. Humans perceive a harmonic series as a single* pitch* whose tonal quality is determined by the exact mix of related harmonics present. Below are illustrated the first sixteen harmonics in the harmonic series for the fundamental, C=65.4Hz. The notes indicating the 7th, 13th, 14th and 15th harmonics occur slightly flat or sharp of the notated pitch.See *harmonic*, *partial*.

**harmonic series tuning** : A tuning system which is based on the first sixty *harmonics* of the *tonic*, resulting in a tuning which is not based on the usual diatonic scale. There are more notes per octave as the tuning progresses up the harmonic series; the top 32 keys of a keyboard cover one octave in pitch.

**harmonic structure** : The sequence of *chords* used in a piece of music.

**harmonic synthesis** : A technique used by *aural enhancers* which creates new high-frequency harmonics not present in the original recording. Adding a small amount of carefully controlled distortion can make a sound quality appear cleaner and more detailed. This happens by sending some dry sound to a side-chain *highpass filter*. The output of the filter is processed dynamically to add *phase-shift* and create synthesized HF (only) harmonics related to the dry signal.

**inharmonic** : Containing frequencies that are not whole-number multiples of the* fundamental*. See *harmonic*, *partial*, *clangorous*.

**subharmonic** : A *harmonic* lower in frequency than the *fundamental*. Sometimes subharmonics are produced by loudspeakers that have poorly controlled cone resonances. The audible effect is a *distortion* component one octave lower than the input signal frequency.

**third harmonic distortion** : That part of *harmonic distortion* which represents only the third *harmonic* (three times the *fundamental* frequency) of a *sine wavepure tone* input to an electronic device. The third harmonic of any tone is musically an *octave* and a *fifth* above the original tone, and is easily noticeable in the output. For this reason, the *MOL* of analog tape recorders, for example, is often specified as that level at which third harmonic distortion reaches 3%..