Editing Musical acoustics (section)

==Scales==

{{Main|Musical scale}}

The material of a musical composition is usually taken from a collection of pitches known as a [[Musical scale|scale]]. Because most people cannot adequately determine [[Absolute pitch|absolute]] frequencies, the identity of a scale lies in the ratios of frequencies between its tones (known as [[Interval (music)|intervals]]).

{{Main|Just intonation}}

The [[diatonic scale]] appears in writing throughout history, consisting of seven tones in each [[octave]]. In [[just intonation]] the diatonic scale may be easily constructed using the three simplest intervals within the octave, the [[perfect fifth]] (3/2), [[perfect fourth]] (4/3), and the [[major third]] (5/4).<!-- Though many musicians know that the diatonic scale is Tone Tone Semi-Tone Tone Tone Tone Semi-Tone. Present the relation-ship of tones and semi-tones... we should add this here along with our sources for the preceding section (user:CyclePat) --> As forms of the fifth and third are naturally present in the [[overtone series]] of harmonic resonators, this is a very simple process.

The following table shows the ratios between the frequencies of all the notes of the just [[major scale]] and the fixed frequency of the first note of the scale.

{| class="wikitable"
|-
! C !! D !! E !! F !! G !! A !! B !! C
|-
| 1 || 9/8 || 5/4 || 4/3 || 3/2 || 5/3 || 15/8 || 2
|}

There are other scales available through just intonation, for example the [[minor scale]]. Scales that do not adhere to just intonation, and instead have their intervals adjusted to meet other needs are called [[Musical temperament|''temperaments'']], of which [[equal temperament]] is the most used. Temperaments, though they obscure the acoustical purity of just intervals, often have desirable properties, such as a closed [[circle of fifths]].