Glossary

Amplitude: The magnitude of pressure variation. Amplitude variations are perceived as volume changes.
Attack: The initial impulse required to create oscillation.
Cent: One 1200th part of an octave. Abbreviation: C. In an equally tempered system, a full tone is 200C, while a fifth is 700 C.
Diatonic scale: An umbrella scale that contains the major and minor keys and the church modes. Two and three whole tones alternate between the semitones.
First harmonic (the fundamental): The fundamental harmonic that usually determines the pitch of the tone.
Flageolet: A flute tone; a very thin, flute-like sound that is produced when the string of a stringed instrument is touched lightly in a certain position (such as near the midpoint).
Formants: Resonants, i.e. frequencies where sound waves are amplified by some point of the vocal tract. Formants can be detected as ridges or peaks in the spectrum of a speech signal.
Fundamental tone: The fundamental harmonic (1st harmonic) that usually determines the pitch of the tone.
Harmonic, overtone: Partial tones of the harmonic spectrum.
Harmonic series: The joint moniker for the series of harmonics.
Harmonic spectrum (harmonic series): The proportions between the harmonics are integer values; the resulting sound is perceived as a tone.
Harmonics, partials and overtones: Different types of partial tones.
Infrasound: Sounds below the hearing range (below 16 Hz).
Inharmonic spectrum (inharmonic partial series): The proportion between the partial tones of the series is not an integer number. The sound is usually perceived as noise (bell-like, hissing, etc).
Microintervals: An interval narrower than a semitone (100 C). A quarter-tone, for example, is 50 C.
Natural harmonics: Tones produced using an instrument that have pitches that correspond with the harmonic series.
Natural tones, natural tone series: Tones produced using an instrument that have pitches that correspond with the harmonic series.
Noise: Sound with no observable pitch.
Octave: An interval that corresponds with the doubling of the frequency. Tones that are one octave apart have the same name. The frequency of the 1st octave a is 440 Hz, while the 2nd octave a is 880 Hz.
Overtones: The harmonics above the fundamental tone (1st harmonic) that affect the timbre of the sound.
Partials: The partial tones of an inharmonic spectrum.
Phon: The measuring unit of loudness. The sound pressure level of a 1000 Hz plane wave that is perceived as equally loud with the reference sound.
Pitch: The interpretation of a complex tone produced by hearing. The pitch of a tone is almost invariably the pitch of the fundamental (1st harmonic) regardless of how many overtones the sound contains.
Pure tone: A sound that includes only one frequency (a sine tone). Partial tones are simultaneously also pure tones. They are called partial tones in order to illustrate the fact that the actual sounds consists of several pure tones.
Resonance: Synchronous vibration. A vibrating system is in resonance when affected by an external force with a frequency that corresponds or is close to the system's own characteristic frequency.
Sine wave: The simplest form of wave motion. Can be easily described with a sine function and only contains one frequency.
Sone: A unit of subjective loudness. 1 sone corresponds with the perceived intensity of 1000 Hz sine tone at 40 dB. The sone value doubles for each additional 10 dB.
Sound spectrum: A graph expressing the proportional volumes of the harmonics.
Syntonic comma: A microinterval of 21.5 C found (for example) between the Pythagorean third and the pure third. Also the difference between a strong and a weak whole tone.
Tone: A complex sound consisting of several harmonics (partial tones).
Ultrasound: A sound above the hearing range (above 20 000 Hz). Many animals, such as dogs and bats, are able to hear ultrasounds.
White/pink/red noise: White noise is noise with many random frequencies. It contains equal intensities of all frequencies (similarly to white colour, which can be considered a sum of all colours). The intensity is increased by 3 dB per octave. In pink noise, the intensity of the sound is equal across all octaves. In red noise, the lower frequencies are stronger.