Eastern Orthodoxy: what is the difference in character between each of the 8 modes? What are each of the 8 modes/tones in the Eastern Orthodox traditions (especially the Byzantine Chant and Russian Chant traditions) meant to convey in terms of spiritual posture, attitude, character, and even theme and dogma?

I know there's a lot to say about each musical tradition, so I want this question's focus to be distinctly, what are the distinguishing features of each mode or tone that set it apart from the others in terms of the spiritual attitude and lessons it is trying to convey (I'm not asking here about the musical theory and rules behind the modes themselves, although I would like to hear explanations of musical rules in terms of how they are used to convey spiritual attitudes and truths).
Byzantine Modes



What does each individual mode convey? What are the goals of expression?

First, I have to explain one small part of the music. Modes 1-4 in Byzantine music, are each a unique scale, while modes 5-8 are a derivation of such, being called Plagal modes. Most often the modes are called 1st-4th mode, and then Plagal First mode, Plagal Second mode, Grave Mode, and Plagal Fourth mode. I won't go into why 7th is called Grave mode since that would probably bring in too much music theory. At times and in my sources you might also see the modes called 1st-8th tones. I won't go into that either; suffice it to say some think mode is a better translation of ἦχος while others think tone is. I'm going to stick with modes and use the plagal names. 
(Savas 42)

Second, just as a good place to start, I'm going to group the modes into their families:


Diatonic: contains 1st mode, Plagal 1st, 4th, and Plagal 4th.
Chromatic: contains 2nd and Plagal 2nd mode.
Enharmonic: contains 3rd and Grave Mode.


These three families were 


  formed by diverse Greek peoples according to the character of each of them. [They were] used by the church in its music, as agreeing wholly with the spirit (pneuma) and character of Christianity. (Savas 41)


It may not have been entirely necessary to group them like that, but I think it groups the overall qualities of the modes as you'll see below, and explains origins a little as well.

Characters of the modes

OK, now while there's no dogmatic character quality for each mode, the general character of the modes can be determined to a point. According to Savas I. Savas (from 53):


Diatonic Modes


1st mode is distinguished by its axiomatic, magnificent, happy and earthly character
Plagal 1st mode is distinguished by its merciful, stimulating and dancing-like character
4th mode is distinguished by its festive, dance-like, and joyous character
Plagal 4th mode: the humble style, the appeasing, the sufferings distinguish this mode

Chromatic Modes


2nd mode is distinguished by its moving, languid, and graceful character
Plagal 2nd mode is distinguished by its funeral-like character and in general its sorrowful tone

Enharmonic Modes


3rd mode is distinguished by its arrogance, bravery, and mature air
Grave mode is distinguished by its manly character and by its strength of melody



If you noticed, Savas grouped the modes into their families. As you can see each of the modes that are related in family, have similar qualities to them.

However, from here things could get a lot more complicated. Each mode can be sung in different styles: sticheraric, heirmologic, etc, changing the tempo of a piece, not through literal rhythm per se, but through a whole change in cadence formula, the amount of notes per syllable, and so on. Often a mode might change from say diatonic to hard chromatic for a certain section.

For a lot of info on musical formulas see the Divine Music Project

We could also go a few other directions, such as aligning each mode with its western mode and thence getting a characteristic interpretation from someone like Guido D'Arezzo. Using this the modes would be:


Diatonic Modes


1st Serious, lends to any feeling, quite happy and very skillful to tame the passions of the soul
Plagal 1st Sad, serious and tearful, much adapted to provoke tears
4th Angelical, belongs to the youth, where pleasure and sadness meet
Plagal 4th The perfect one, to wisdom, has to be very glad

Chromatic Modes


2nd Makes happy, causes happiness and pleasure to those who are in sadness
Plagal 2nd Devout, tearful and pious

Enharmonic Modes


3rd Mystic, Vehement, effective to incite anger
Grave Harmonious, has tender effects



(Savas, Canticum)

However, you can see that these two different interpretations don't line up for every mode. I'm of the mind that this second interpretation is better for Gregorian Chant.



Russian Modes



Here things are quite a bit different. Though there have been several types of Russian Chant (Znamenny chant is a different story), what is used most today has been greatly influenced by the European west most especially during the 17th-18th centuries (Simmons). What has come out is much different in that it is Polyphonic as opposed to the Byzantine Monophonic style, i.e. 4 part harmony as opposed to a single melody line with supporting ison.

While the role of a chanter in the Byzantine style is:


  not to impose on the chant any personal meaning or emotion, but to realize in song the meaning and the feeling that are there in the text and the music. (Melling 26)


Russian chant, influenced by the west is very much about bringing out the physical emotions. It's Renaissance style. As Metropolitan Eugene of Kiev said:


  they have often disregarded the sanctity of the place and subject of their compositions, so that, generally speaking, it is not the music which is adapted to the sacred words, but instead the words are merely added to the music and often in a contrived manner. Apparently, they wanted more to impress their audience with concert-like euphony than to touch the hearts with pious melody, and often during such compositions the church resembles more an Italian opera than the house of worthy prayer to the Almighty. (Drillock)


Now while I find that a little harsh, I'm also finding it hard to speak about the goals of Russian Common Chant in the same way as Byzantine. This isn't just about me not being able to find any sources, though that's part of it. In the Russian modes (maybe in this case more correctly tones), several are in the same scale and there is none of the correlation between modes we see in Byzantine. This means we can't break them into the families or relate all of them to the Western Modes which have general characteristics e.g. per D'Arezzo. Some of them could be shown to have equivalent scales, but I can't do that right now, nor can I find a source that has.