Echos

echoi ἦχοι [ˈiçi]; Old Church Slavonic: гласъ [glasŭ] "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").

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.

Early treatises only state the initial or "base" degree (η βασή) which is the tone sung as a burden (ἴσον) by certain singers of the choir called isokrates in order to support any melody composed in a certain echos.

This short form was used in two different ways, as main signature (in the table called αἱ μαρτυρίαι τῶν ἤχων, "the witnesses of the echoi") it indicated the echos of a whole composition, but especially in sticheraria notators also wrote medial signatures (in the table called αἱ μαρτυρίαι τῶν φθόγγων, "the witnesses of phthongoi", pitches memorised by echemata) between the neumes above a kolon of the text, in order to indicate that the melos changed here into another echos.

Within the dialogue treatise (erotapokriseis) a catalogue of short formulas memorizes each echos of the Hagiopolitan octoechos and its two phthorai (νενανῶ and νανὰ).

Περὶ πλαγίων Ἀπο τοῦ πλαγίου πρώτου ἤχου πάλιν καταβαίνεις τέσσαρας φωνάς, καὶ εὑρίσκεται πάλιν πλάγιος πρώτου· ὅυτως δὲ / ἄνανε ἄνες ἀνὲ ἄνες· Ὁμοίως καὶ ὁ β' ἤχος καταβαίνων φωνάς δ', εὑρίσκεις τὸν πλάγιον αὐτοῦ, ἤγουν τὸν πλάγιον τοῦ δευτέρου.

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.

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 (Περὶ τοῦ Τροχοῦ) according to a current practice of parallage, which was common to 18th-century versions of Papadike: Τὸ δὲ Πεντάχορδον, τὸ ὁποῖον λέγεται καὶ Τροχὸς, περιέχει διαστήματα τέσσαρα, τὰ ὁποῖα καθ᾽ ἡμᾶς μὲν εἶναι τόνοι.

[7] Chrysanthos' exegesis just passed the protos pentachord D (πα)—a (κε) in an ascending movement, before using the cadence pattern to the base degree of the mode.

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.

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 νη—γα (C—F) and δι—νη' (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.

Hence, the enharmonic tritos echoi are not separated by a pentachord, but usually both set on F (γα, phthongos γ' as well as υαρ), 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 (Ἄξιον ἐστίν), the diatonic melos of echos varys was chosen.

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.

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),[15] echoi are not attributed to specific composers, but are rather regarded as belonging to the collective and anonymous heritage of liturgical chant.

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.