A tetrachord consists of four notes on consecutive lines and spaces of the staff.
Four different tetrachord patterns occur between consecutive white keys on the piano. They are distinguished by the pattern of whole steps and half steps.
W = Whole step, H = Half step
| CDEF | |
|
| GABC | |
|
| DEFG |  |
|
| ABCD |  |
|
| EFGA |  |
|
| BCDE |  |
|
| FGAB |  |
|
A scale consists of an indeterminate number of pitches arranged in consecutive order spanning an octave.
The basic diatonic scales use eight consecutive white keys on the piano and span one octave. There are seven basic diatonic scales: C-C, D-D, E-E, F-F, G-G, A-A, and B-B. Each basic diatonic scales consists of a lower tetrachord and an upper tetrachord joined by a whole step or half step. The lower tetrachord, upper tetrachord, and connection step are different for each scale.
A Mode or modal scale consists of eight note spanning and octave. Modal scales that start on white keys correspond to the seven basic diatonic scales. The names of the seven modes are: Ionian, Dorian, Phrygian, Lydian, Mixolydian, Aeolian, and Locrian. While the basic diatonic scales start on white keys, modal scales can start on any key but must follow the whole step half step pattern of the corresponding basic diatonic scale. Modal scales were used in the medieval and renaissance periods and are also used in pop and jazz music today.
 |
|
 |
|
 |
|
 |
|
 |
|
 |
|
 |
|
Revised by John Ellinger, Spring 2012.