@TIF good question on the real use of two strings:http://www.forumancientcoins.com/catalog/roman-and-greek-coins.asp?radd=1&vpar=18&zpg=93001 "The kithara (cithara) was an ancient stringed musical instrument resembling the lyre. The lyre was a simpler folk-instrument with two strings and tortoise shell body. The kithara had seven strings and a flat back. The kithara is a symbol of Apollo and he is credited with inventing it. Its true origins were likely Asiatic.. The kithara was primarily used by professional musicians, called kitharodes. In modern Greek, the word kithara has come to mean "guitar."- from Forum from Forum but this one has more than two?
That instrument on that coin is a kithara, and from the passage you posted and from what I've seen, kitharas were more sophisticated and had more strings. I didn't realize some lyres have only two strings! I'm not sure that passage is accurate-- I suppose there were varying numbers of strings though. I have seen some modern folk instruments with two strings, such as the instrument you showed a few posts upstream. I guess it has its roots in ancient lyres?
It might be a bit much to assume that all Greek musicians even played with the same tunings or recognized any need to play chords, use 12 tones or octaves as we define them. Even if you have a treatise explaining tunings, it does not rule out other options. Perhaps you recall how 'wrong' it sounded to your 'normal' ears when you first heard 12 tone Western or any form of Eastern music. Do we even know that these instruments were played singly? Today's handbell choirs play chords all the time but they use more than one human ringer to get more than two notes at a time. Like everything else having to do with antiquity, we can learn more if we avoid assuming things obvious to us but not to the people from 'back then'. I can't carry a tune in a bucket.
from wikipedia on the "Cithara" says the original Lyre had two strings, the Ionians show this clearly in many diobols. Joe from Forum must have researched it up. "The kithara was a professional version of the two-stringed lyre. As opposed to the simpler lyre, which was a folk-instrument, the kithara was primarily used by professional musicians, called kitharodes. The kithara's origins are likely Anatolian.[2] The barbiton was a bass version of the kithara[3] popular in the eastern Aegeanand ancient Anatolia." https://en.wikipedia.org/wiki/Cithara
Interesting! I'll have to start counting strings on every ancient coin lyre coin I see . Based on ancient art and coins some lyres have more than two strings, but perhaps the "original" instruments only had two? Perhaps there were many variations, many different names of specific instrument types or subtypes of "lyres".
I'll see your lyre and raise you one and an owl. 19-18 mm. 3.29 grams. Trajan drachm. ΔHMEΞ YΠAT B [second consulship] Struck at an uncertain mint in Lycia. Sear Greek Imperial 1046. SNG von Aulock 4267.