Octoechos (also Octoichos; Greek: Ὀκτώηχος, from ὀκτώ "eight" + ἦχος "sound, mode") is the fundamental structure for classifying and describing modes (echoi) in Byzantine music.
Musical Modes
Origins and early theory
According to tradition, the theory and practice of echoi were codified into a system comprising eight modes, which is called the Octoechos - meaning literally "(the system of) eight echoi". These eight echoi are the four kyrioi (authentes) echoi and the four plagal echoi. However, even the earliest theoretical treatises point out that there are two more modes which do not fit into this system: nenano and nana. This early and very simple account of the modal system bears parallels to those of early Arabic music theorists of the 9th century or earlier. Musicological research from the 1960s onwards[weasel words] has stipulated that the Octoechos is based on music theory of the Jewish chant and that this itself has inherited the eight-modes concept of Babylonian origins. The simplicity of a system with eight modes (plus two ancillary modes) may be a main reason for its persistence throughout Western and Eastern medieval music theory and up to these days in Byzantine chant. There is no genuine precedent in Hellenistic theory for a system of eight modal categories,[1] but the success of the Western synthesis of this system with that of the De musica of Boethius created the false impression that the Byzantine system of the oktōēchos was inherited directly from ancient Greece.
The question of general (interval-structures of the scales)
The development of musical theoretical concepts and their associated notational signs (neumes) in Byzantine music strongly suggests that nenano and nana stood conjointly for degrees that deviate from the 7 diatonic degrees of the scale and for modes that are associated with these degrees. This raises the question whether music in the near eastern Middle Ages was entirely diatonic. Some 19th century and early 20th century musicologists claimed that Arab music as well as Western medieval chant and Byzantine music were essentially diatonic and went so far as to challenge the capability of humans to distinguish and to sing microtonal inflections with any accuracy (but see also microtone). However outmoded this view may seem now, it is closely reminiscent of arguments amongst music theorists that started as early as late classical antiquity. Major Hellenistic theorists such as Ptolemy and others stated that the enharmonic genus was extinct since early classical times, while the chromatic genus was only rarely mastered, and on its way to extinction.[citation needed] Also, early Arab theorists such Ibn al Munajjim and Ishak al Mawsili base their systems on the diatonic pythagorean scale. The struggle to accommodate microtonal inflections and non-diatonic scales in the modal system is an ongoing topic in near-eastern theory.[citation needed] The mathematical, theoretical and notational tools developed are often confusing and not easy to grasp. Thus on the whole one may say that the subject of non-diatonic scales and microtonal inflections is as difficult to formalize theoretically and to master in practice as it is attractive.
Extent of the system in practice, other systematization attempts
The system of echoi is far more diverse and developed than a cursory look at the basics of the theory suggests. In practice, the system of echoi is complex and its details are encoded in the notation and in the nomenclature of derived echoi or of echoi variants. An interesting attempt at capturing the full extent of the modal system with a quasi-systematic nomenclature was published by Simon Karas in his multi volume work on the theory and practice of Greek music. Other valuable sources of information are treatises comparing the echoi with their corresponding Ottoman (Turkish) makamlar (see makam). Such are the works by Kiltzanidis (published in the late 19th century) and Kyrillos Marmarinos (his own original manuscript dated AD 1747, stored in the archives of the Historical and Ethnological Society of Greece, Athens).
Indications of other systems and traditions in classical manuscripts
The diversity of modes and the inadequacy of the Octoechos as underlying model for their classification was explicitly acknowledged in important manuscripts of mature Byzantine music theory such as the Hagiopolites. The Hagiopolites points out that in fact there is a multitude of echoi beyond those of the Octoechos and calls these more numerous and combinatorially complex echoi the modes of the "Asma" (literally: Song). This clearly suggests a distinction of two repertories and/or traditions. While there exist as yet no definitive conclusions as to the nature of these traditions, their names do suggest a possible distinction between repertories of Jewish-religious origin and hellenistic (pagan or mixed multicultural) origin. Music theoretical manuscripts emphasize that the origin of the Hagiopolites ("Hagia Polis" = "Sacred City") is the sacred city (of Jerusalem?), or the City of Saints, which suggests the religious origins of the system of echoi represented in the Octoechos. On the other hand we have no clear indications about the nature of the tradition of the "Asma", whether it was of distinctly "secular" origin or whether it denotes some type of syncretic and enriched musical tradition that developed within the practice of ecclesiastical chant in the Mediterranean basin.
The Byzantine Modes (or Tones) as currently used in the hymns of the Greek Orthodox Church and other churches that use Byzantine Chant are analogous to the church modes found in Gregorian chant. However, whereas in Gregorian chant a mode refers to a set of notes on a scale, Byzantine Tones are more of a system or organization of notes that have defining characteristics, including a set of notes or scales, rhythm, tempo, base note (ison), melodic pattern (prosomion), accents and cadences (melodic endings). The eight Byzantine Tones are:
First Tone
Second Tone
Third Tone
Fourth Tone
Plagal First Tone (Tone Five[5])
Plagal Second Tone (Tone Six)
Grave Tone (or Barys) (Tone Seven)
Plagal Fourth Tone (Tone Eight)
Hymns are typically divided into three gernes according to their context.
Papadic hymns are based on pre-christianic (that is old testament) text
Sticheraric hymns have "idion melos" (that is their own music) and are typically preceded by a psalm verse, "stichos"
Heirmologic hymns are based on musical patterns, "heirmoi","automela" or "prologi"
This classification reflects into the structure of the hymn's melody. Hymns of the same tone belonging to different gernes are structured musically in a different way. This holds true for hymns belonging to every tone (with the possible exception of the third tone) but for some tones like the fourth or the grave tone it is apparent. There is a popular misconception that the division into gernes is based on the complexity of the melody versus the text. According to this misconception heirmologic hymns have one note per syllable, sticheraric two or more notes per syllable and papadic many notes per syllable. However one can encounter hymns of the three gernes with exactly the same notes per syllable ratio. For example "syntomoi polyeleoi" or "doxologiai", "syntoma stichera" and "katavasiai" have all typically two notes per syllable, the first two being papadic hymns (based on psalmic text), the third sticheraric and the fourth heirmologic. That being said, typically the heirmologic hymns are faster than the sticheraric and the sticheraric faster than the papadic.
There are typically two main notes that define each of the Byzantine Tones. The base note or ison is the final note on which the hymn ends. The ison is typically droned against the melody. Any other notes different than the ison that occur more often than others during the course of a hymn are called dominant notes and also help define the Tone. The plagal (oblique) tones mentioned above employ the same scales as their counterparts, however their base notes (ison) are a fifth below that of their counterparts.
Scales
Byzantine music does not distinguish between major and minor scales. In fact, some Byzantine scales cannot even be played on a conventionally tuned piano. Byzantine scales have precise tunings that have some intervals smaller than the Western half-step. These are called microtones. Whereas Western music has two scales (major and minor), Byzantine music has four scales:
The diatonic scale begins and ends on C, with the exception that the E and the B are slightly flatter, micro-tonally, than in 12-equal temperament. Furthermore if the melody of a hymn in the diatonic scale is ascending, the B is natural and flatted (micro-tonally) when descending. The diatonic scale is the most common scale for the First, First Plagal, Fourth and Fourth Plagal Tones. To western ears, the diatonic scale sounds similar to the Western natural minor scale or the Aeolian mode.
The enharmonic scale is tuned exactly like the Western major scale with the main note (ison) on F. The enharmonic scale is the only Byzantine scale that can be played accurately on the 12-equally tuned piano or other keyboard instrument. The Third and Grave Tones are enharmonic except for a diatonic, papadic variant of the Grave Tone.
The hard chromatic scale is usually based on D of the lower tetrachord with the second step slightly flatter and the third step slightly sharper (micro-tonally) than the flat and sharps of Western music. The longer rhythmic styles of the Second Plagal and some Second Tones use the hard chromatic scale.
The soft chromatic scale also uses the lower tetrachord but is based on C instead of D. There is some controversy about how much to “flat” the second note (D-flat) of the lower tetrachord as compared to the second note (A-flat) of the upper tetrachord of the soft chromatic scale. Traditionally, the D is flatted more than the A. Currently, however, the argument is that both should be flatted the same making both the upper and lower tetrachords equal, thus identical to the hard chromatic scale. The Second, Fourth and Second Plagal Tones all use the soft chromatic scale.