Michael Psellos loves his particles and articles -- a love which I am having difficulty translating a certain section:

μᾶλλον δέ, ἵνα τὸ ἀκριβέστερον εἴπω, ἐκεῖνο μὲν ἀμετάβλητον μένει καὶ ἀναλλοίωτον, ἡμεῖς δὲ περὶ ἐκεῖνο μεταποιούμεθα καὶ μεταβαλλόμεθα. ὥσπερ γὰρ μιᾶς ἀπηχηθείσης ἐν ὑπαίθρῳ φωνῆς ὁ μέν τις ἡμῶν ἤκουσεν, ὁ δὲ οὐκ ἤκουσε, καὶ τῶν ἀκουσάντων ὁ μέν τις τρανέστερον, ὁ δὲ ἀδρανέστερον ἀντελάβετο κατὰ τὴν ἀναλογίαν τῆς διαστάσεως καὶ τῆς εἰλικρινοῦς ἀκοῆς, τῶν δὲ μή ἀκουσάντων ὁ μὲν διὰ τὸ πολύ διεστάναι οὐκ ἀντελάβετο...

The following is what I am trying to figure out:

1. the occurrences of ὁ δὲ and ὁ μέν what does it mean in this context? LSJ suggests that ὁ δὲ means "the former" and ὁ μέν means "the latter" but I don't think this is the full meaning here. Perhaps ὁ is referring to something ambiguous that is not quite understood yet and should be translated "the thing". I have found one translator using "individual" as the translation of ὁ μέν. It makes sense, but it fails to bring clarity to the English reader. Another approach could be that this is used as relative pronoun "which". A further solution could be that ὁ relates to a previous subject or person, but there is no previous masculine subject or person in the text. So that is eliminated.

2. why there is different diacritics between δέ and δὲ, μέν and μὲν in this text. What does that mean? I haven't found any documentation on this, except that in different texts where this is also found, translators have ignored this difference in diacritics.

3. The reversing of μὲν and δὲ in the line: τῶν δὲ μή ἀκουσάντων ὁ μὲν διὰ -- does this make μὲν simply emphatic of δὲ and should be translated as "indeed"?

I am not sure how to exactly approach these. Any thoughts would be appreciated.

ὁ μέν τις ἡμῶν ... ὁ δὲ = someone of us ... some other

diacritics between δέ and δὲ are the grave and acute accents (check more on this at the language pages, www.ellopos.net/elpenor/lessons/greek-accentuation.asp?pg=2" target="_blank">https://www.ellopos.net/elpenor/lessons/greek-accentuation.asp?pg=2 ).

τῶν δὲ μή ἀκουσάντων ὁ μὲν διὰ τὸ πολύ διεστάναι οὐκ ἀντελάβετο... = as regards those who didn't listen, one did not perceive anything because of being too far away...