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# Module 2 - Psychoacoustics

### Scales

The word "scale" is derived from a Latin word (scala) meaning "ladder" or "staircase." A musical scale is a succession of notes arranged in ascending or descending order. Most musical composition is based on scales.

Western music divides the octave into 12 steps called semitones. All the semitones in an octave constitute a chromatic scale or 12-tone scale. However most music makes use of a scale of seven selected notes, designated as either a major scale or a minor scale and carrying the note name of the lowest note.

For example, the C-major scale is played on the piano by beginning with any C and playing white keys until another C is reached. (from the textbook page 171)

Mathematically, musical scales are constructed using ratios of frequencies rather than adding and subtracting frequencies.

To successfully complete this chapter you should...

• Read chapter 9 in your text book (pages 171 - 185).
• Carefully study the important concepts.
• Be able to identify the construction of commonly used musical scales.
• Be able to determine the frequencies for scales using just intonation, Pythagorean, meantone, and equal temperament.
• Be able to convert between frequency ratios and "cents.".

#### Important Concepts

Musical scales
Pentatonic
Chromatic
Diatonic
Semitones
Scales and temperaments
Just intonation
Pythagorean scale
Meantone temperament
Equal temperament
Electronic tuners
Ratios
Cents

Copyright 2008, by the Contributing Authors. Cite/attribute Resource . admin. (2005, January 25). Module 2 - Psychoacoustics. Retrieved January 07, 2011, from Free Online Course Materials — USU OpenCourseWare Web site: http://ocw.usu.edu/Electrical_and_Computer_Engineering/Science_of_Sound/Module_2_-_Psychoacoustics_5.htm. This work is licensed under a Creative Commons License