Echos (Greek: ? ['ixos] "sound"; pl. echoi ? ['içi], Old Church Slavonic: [glas?] "voice, sound") is the name in Byzantine music theory for a mode within the eight mode system (oktoechos), each of them ruling several melody types, and it is used in the melodic and rhythmic composition of Byzantine chant ("thesis of the melos"), differentiated according to the chant genre and according to the performance style ("method of the thesis"). It is akin to a Western medieval tonus, an Andalusian tab', an Arab na?am (since 1400 "maqam"), or a Persian parde (since 18th century dastgah).
In general, the concept of echos denotes a certain octave species, its intervallic structure as well as a set of more or less explicitly formulated melodic rules and formulae that represent a certain category of melodies within the musical genre. As such, echos is the basis for composing or improvising new melodies that belong to it, as well as for properly performing existing pieces that have been written in it. These rules include the distinction of a hierarchy of degrees (tones, notes), where certain degrees figure as cadence notes (?) around which the melody will revolve prominently, or on which the melody will end most of the time. However, only very late stages of the theory (19th-20th century) actually provide systematic descriptions of echoi, while earlier stages use mostly diagrams, indirect descriptions and examples. Explicit detailed descriptions must still be provided based on extensive analysis, as is the case with modal phenomena in numerous other cultures.
Early treatises only state the initial or "base" degree (? ?) which is the tone sung as a burden (?) by certain singers of the choir called "isokrates" in order to support any melody composed in a certain echos. By this support singers (psaltes) could easily recognise the relative position of each note as it was organised by tetrachords based on the basis note of each echos. This base degree of the mode was communicated by an intonation formula of a foresinger, known as enechema.
There are different forms to notate enechema which are crucial to understand the different chant books and their notation. All these forms were written in red ink. The explicit long form was called by Jørgen Raasted intonation, but only the books of the cathedral rite used such explicit intonations, also between the sections, where these intonations were called medial intonation. This explicit form made sense, since the intonation also communicated the changes between the left and the right choir and their leaders performed these intonations to coordinate these changes. There was a short form as well which was called modal signature. It indicated the echos by the numeral like ' for "plagios protos," while the neumes sung with the last syllable of the enechema were written above right to the numeral. This short form was used in two different ways, as main signature it indicated the echos of a whole composition, but especially in sticheraria notators also wrote medial signatures between the neumes above a kolon of the text, in order to indicate that the melos changed here into another echos. The traditional Greek term for these medial signatures was "martyria" (), since the medial signature also "testified" the phthongos of the cadence made at the kolon.
Within the dialogue treatise (erotapokriseis) a catalogue of short formulas memorizes each echos of the Hagiopolitan octoechos and its two phthorai ( and ?). These formulas are also called "echemata" (?)--or more often "enechemata" () or "apechemata" (). The use echemata was also imitated by Carolingian cantors who used similar intonation formulas and collected them in a separate book called tonary.
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The enechemata of the medieval eight diatonic echoi already present a fundamental difference to the Carolingian octoechos:
More information on the structure of echoi is only indicated in a very rudimentary way through diagrams involving neumes--the Byzantine round notation. The details of the actual intervallic and melodic structure of echoi are virtually impossible to deduce from theoretical treatises prior to the 18th century. In fact, only relatively late systematic comparisons of the echoi with the makamlar of Ottoman court music, such as those by the Kyrillos Marmarinos, Archbishop of Tinos, in his manuscript dated 1747, and the reform of the Byzantine notation by Chrysanthos of Madytos at the first half of the 19th century make it possible to understand the structure of echoi and to attempt reconstructions of melodies from earlier manuscripts.
He already introduced his readers into the diatonic genus and its phthongoi in the 5th chapter of the first book, called "About the parallage of the diatonic genus" (? ? ? ). In the 8th chapter he demonstrates, how the intervals can be found on the keyboard of the tambur.
Hence, the phthongoi of the diatonic genus had been defined according to the proportions, as they were later called the "soft chroa of the diatonic genus" ( ? ?). For Chrysanthos this was the only diatonic genus, as far as it had been used since the early church musicians, who memorised the phthongoi by the intonation formulas (enechemata) of the Papadic Octoechos. In fact, he did not use the historical intonations, he rather translated them in the Koukouzelian wheel in the 9th chapter (? ) according to a current practice of parallage, which was common to 18th-century versions of Papadike:
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The pentachord which was also called wheel (), contains four intervals which we regard as certain tones [? , , and 2 ]. The four intervals spanned five phthongoi:
["" means here the fifth-equivalent for the protos']
These five stations of the pentachord could be memorised by the echemata of the kyrioi echoi in ascending direction or by those of the plagioi echoi in descending direction (see Chrysanthos' explanation of the trochos parallage). Each of these echemata had the potential to develop an own melos within its melody types:
Each echema is followed by the incipit of a sticheron ideomelon which illustrates a certain melos of the echos. The following book Kekragarion illustrates, how the hesperinos psalm has to be sung according to the sticheraric melos of each echos. The Kekragarion was later included in the printed editions of the Anastasimatarion or Voskresnik.
In the chapter "On the apechemata" (? ?) of his "Great Theoretikon", Chrysanthos translated the Byzantine octoechos and its intonation formulas (apechemata, or enechemata), as they could be found in the Papadikai, by offering an exegesis of the papadic apechemata in comparison to the simpler forms used by Orthodox chanters today. They served as kind of model for the composition within a certain melos, similar to the seyirler of an Ottoman makam.
For the diatonic echos protos, the medieval enechema had the finalis on the top of the protos pentachord, while the enechema passes through it:
Chrysanthos made this exegesis to explain the melos of the whole echos:
In the first descending half he made the usual cadence on D (, phthongos ') which corresponds to the finalis of the modern melos, while it was once the finalis and the basis of the plagios protos. The second half, when the melos raises again, but within the papadic melos (used with a cherubikon or koinonikon) it prepared a change to another base tone on the upper tetrachord like a (, phthongos ?').
Hence, according to the current practice of Orthodox chant the protos mele were rather based on the lower tetrachord, but the formula could be used a fifth higher likewise. The step between the phthongoi of tetartos (?') and protos (?') could be C--D (--) or G--a (--).
Concerning the enechema of the plagios protos, it had not changed during the centuries.
Unlike the tradition which always used register changes, the modern interpretation did not fix the base degree of echos plagios protos to the bottom of the pentachord, it could appear regularly at the top like in the troparic and heirmologic melos: a ()--c (')--b (')--a () or D ()--F ()--E ()--D ().
Chrysanthos' exegesis just passed the protos pentachord D ()--a () in an ascending movement, before using the cadence pattern to the base degree of the mode.
Chrysanthos' bridges between the diatonic echos devteros of the Byzantine past and the chromatic melos of the present Orthodox traditions. The latter is characterised by the constant use of the mesos form, which is not on the phthongoi of devteros--b natural (', phthongos ?') and E (, phthongos '), but between them on G (, phthongos ').
The usual diatonic kyrios form was this enechema, but only the descending part would lead to the base tone of the mesos devteros.
As a consequence, Chrysanthos' exegesis starts and ends on this mesos, but it follows the Hagiopolitan convention to pass through the former devteros pentachord, but he even passes through the tetartos pentachord C (, phthongos ')--G (, phthongos ?'), as it used by the current melos of echos devteros.
Nevertheless, according to the very particular interpretation of Chrysanthos the melos and scale of echos devteros is ruled by a diphonic organisation based on just two diatonic intervals: the major and minor tone. As a result, the octave C--c between and ' becomes slightly diminished. Chrysanthos' concept of diphonia was so radical that it found no commonplace in current chant manuals, instead a lot alternative interpretations proposed various divisions of the chromatic tetrachords between -- (C--F) and --' (G--c).
At the end of his chapter "on the apechemata" Chrysanthos offers a separate exegesis of phthora nenano as a modern deduction of the plagios devteros enechema, whose medieval form was this. But it had moved now with the phthora nenano to the phthongos of plagios protos.
Chrysanthos did not offer any exegesis for the apechema of the diatonic echos tritos. He only mentions the intonation of phthora nana instead, which is still used as the echos tritos intonation formula in current Orthodox traditions.
The same enharmonic interpretation was done with the plagios called "echos varys" (grave mode), obviously in certain cases, when the plagios tetartos was expected of fourth under the base tone. Hence, the enharmonic tritos echoi are not separated by a pentachord, but usually both set on F (, phthongos ?' as well as ), in troparic, sticheraric and heirmologic mele:
Within the papadic chant genre (cherubika, koinonika), but also during the composed recitation of Polyeleos psalms and kalophonic heirmoi ( ), the diatonic melos of echos varys was chosen. Its base tone was one phthongos below the plagios tetartos. According to Chrysanthos it diminished the tritos pentachord to a kind of tritone, at least when it was set on fret arak of the Ottoman tambur, but there are also more traditional ways of intonation depending on the local school of a chanter.
The original tetartos pentachord between plagios and kyrios--C () and G () or likewise G () and d (')--does still exist in the papadic melos of echos tetartos, which is known as the "papadic Agia" (? ).
Chrysanthos made for the papadic melos this exegesis.
A commonly used form of ? might be the one which Chyrsanthos mentions as the one used by Petros Peloponnesios.
The diatonic plagios of tetartos according to the enechema known from the treatises called Papadikai
which was interpreted by Chrysanthos, as follows.
Since the plagios devteros has moved to the phthongos of plagios protos ('), the original phthongos of the diatonic plagios devteros was vacant. In fact, as a diatonic phthora it was represented by a medial signature of the so-called "echos legetos" (? ?) which had preserved the diatonic intonation of plagios devteros.
The signature was used within the heirmologion kalophonikon, since heirmoi of devteros echoi were still treated as a diatonic melos unlike the school of Petros Peloponnesios and his follower Petros Byzantios. According to their school the echos legetos was part of the tetartos echoi, as a mesos tetartos it was used for the heirmologic melos, where the base and final degree was a low intoned E (), and for the sticheraric melos, which had the base degree of the mode and closing cadences on D (), but the concluding finalis E ().
Chrysanthos interpreted also echos legetos as a diatonic mesos tetartos.
He also mentioned a common enechema as it was used by Iakovos the Protopsaltes.
In this last paragraph of the chapter about the apechemata Chrysanthos referred to ten echoi within the tradition of Hagiopolites.
? ? · ?. ? ?, ? ? , ? .
The echoi of the psalmody are eight. The apechemata preserved though are ten, because the echos tetartos, and the plagios of the devteros, have two apechemata each.
But unlike the Hagiopolites, where the phthora nana was mentioned as a "mesos tetartos" and the nenano phthora as "mesos devteros", echos legetos seemed to have slipped into the mesos tetartos role, but it was a diatonic mesos, not an enharmonic like phthora nana. In fact, Chrysanthos could not longer mention nana and nenano as additional echoi, since their melos had already replaced the diatonic mele of the devteros and tritos echoi.
In other Ottoman music traditions like the list of composed Mevlevi dance suites as models of well-known and new makamlar created by eponymous masters resulted in a proliferation of modes (makamlar, maqamat), echoi are not attributed to specific composers, but are rather regarded as belonging to the collective and anonymous heritage of liturgical chant. Eponymous compositions do exist throughout most of the history of Byzantine chant, but their echos is always classified from within the system of existing echoi. Due to an interest for makamlar compositions Phanariotes like Georgios the Protopsaltes, one of the great teachers of Orthodox chant, also became a student of the dervish composer Dede Efendi, after he had learnt Turkish. Byzantine notation developed as a universal notation system during the 19th century which includes even attempts to integrate makamlar within the mele of the Octoechos, while ornamental details became part of an oral tradition.
The system of echoi is rich and diverse. Closer study and comparison with modal systems of neighboring cultures reveals a complex network of cultural and ethnic influences throughout the centuries--a vivid exchange between musicians across the borders of ethnic and religious identity (Phanariotes). The basic theory of echoi is formalized in a system of eight modes called the Octoechos. See the article Neobyzantine Octoechos for a discussion of its origins and a critique of this concept vis-a-vis actual practice.