Echos (Greek: ἦχος [ˈixos] "sound", pl. 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"). It is akin to a Western medieval tonus, an Andalusian tab', an Arab naġam (since 1400 "maqam"), or a Persian parde (since 18th-century dastgah).
You might not be a big fan of Echos, maybe you're here for just one song by Echos that you like, but take a look at the rest, they might surprise you.
Analyzing the lyrics of Echos's songs can be a lot of fun and if you enjoy composing, it can help you find formulas to create your own compositions.
Sometimes Echos's songs help us express what we think or feel. Is that the case for you?