The eight tones are split into two sub-groups: the authentic tones and the plagal tones. Each of the plagal tones is closely related to its corresponding authentic tone. The first four tones are the authentic tones; the second four are the plagals. Thus, tone 5 is the plagal of 1, 6 is the plagal of 2, and 8 is the plagal of 4. In contemporary practice, the enharmonic mode of tone 7 is performed as if it were the plagal of 3; but the more ancient form of the seventh tone is diatonic, and is not related to the third at all. In Greek the seventh tone is always referred to as the βαρυς (grave) tone. This refers to the low, or grave, note which is the vasis (root) of the scale of the ancient 7th tone. Nowadays this mode of the 7th tone is rarely encountered; usually we use a variant of the 3rd instead.
In Byzantine practice we often do not refer to the notes as A B C or do re mi; instead, we refer to them by their Greek names. The ascending scale of C would thus be named:
| νη | πα | βου | γα | δι | κε | ζω | νη' |
| ni | pa | vu | ga | dhi | ke | zo | ni' |
These notes were named after the first seven letters of the Greek alphabet, thus:
pa
bou
ga
di
ke
zw
nh
There are three main divisions of scales in use with Byzantine music: diatonic, enharmonic, and chromatic. The chromatic modes may be further broken down into the hard chromatic and the soft chromatic; however, since the differences between these are microtonal, they do not merit our attention at the introductory level, and only passing reference will be made to them.
The diatonic scale is (for the purposes of the Western ear) essentially made up of the white keys on the piano. In some tones the ζω (B or ti) may be flatted, in accordance with a rule called the law of attraction of sounds. (In reality the diatonic scale is not exactly the tempered scale of our piano -- it is closer to the "just" scale used for tuning in the 18th century; βου and ζω are flatted by 1/3 of a half step.)
The enharmonic scale is (once again, for our purposes) the F major scale. It is an equal-tone scale, meaning that it corresponds to the F major scale on the piano. This means that ζω is always flatted unless explicitly notated otherwise. The real difference between the diatonic and enharmonic scales lies in the microtones.
The chromatic scale is executed as follows:
| πα | βου | γα | δι | κε | ζω | νη | πα | |||||||
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(In the soft chromatic, the half steps are slightly more than half (specifically 2/3 of a step), and the 1 1/2 steps are slightly less than 1 1/2 (actually 1 1/3 of a step).
(Also note: The chromatic scale does not necessarily begin on πα.)
There are three basic tempos which we encounter in Byzantine music, depending upon the hymn:
The irmologic tempo is the fastest, and is used for the majority of hymns. Generally one to three notes are associated with each syllable of the text.
The stikhiraric tempo is slower, and is used for hymns such as "Lord, I have cried" at Vespers and "Let every breath praise the Lord" at Orthros. It is also used for many Theotokia. Generally up to a dozen notes may be associated with each syllable of the text.
The papadic tempo is very slow, and is used for a small number of hymns such as the Cherubic Hymn and for hymns which must fill a larger amount of time, such as the Koinonikon. An entire page of notes may be used for a single syllable.
The tempo of a hymn may affect not only how many notes get sung, but also which note a given phrase might end on.
