Peterson AutoStrobe 490ST - Manual (Page 30)

Page 36
GLOSSARY
cent - an audio frequency interval which is defined by the division of an equally-tempered semitone interval into 100 equal-
ratio steps. Each cent is
1200 / 2 times the previous one in frequency, making it about 0.058% higher in frequency than the
previous one.
equal-tempered - type of note scaling within a musical octave in which a perfect 2:1 octave frequency ratio is divided into
equal-ratio scale notes. In a twelve-tone scale, each note's frequency is
12 / 2 times the previous one making each scale note
about 6% higher in frequency than the previous one.
equal temperament - a musical scale in which the scale notes are at equal ratios from one to the next. In a twelve-
tone/octave scale, this ratio is
12 / 2 making each scale note about 6% higher in frequency than the previous one. This scaling
choice provides for identical musical intervals regardless of the root note used for the key signature. In exchange for this
flexibility, all intervals have varying degrees of built-in dissonance associated with them.
stretch - a scaling of the musical octaves (and the notes within) in an instrument so as to cause overtones in the lower-pitched
notes to more closely match the fundamental frequencies of higher-pitched notes. Such adjustments improve the overall
impression of harmony in instruments which utilize physically non-linear sound-producing mechanisms (such as pianos,
harps, and most percussive instruments).
temperament - frequency scaling of the notes within a musical octave.
timbre - the “character” or quality of a sound, distinct from pitch and volume, which distinguishes one sound from another.
All natural sounds may be thought of as containing various simple-tone (sinusoidal) frequencies in varying strengths. It is
the relative strength and frequency of these over-tones or “partials” and the manner in which these parameters change over
the course of the sound that makes a note from a piano, for example, distinguishable from that of a trumpet.