It is examined whether a chelys-lyre could be used, at least as an exception, instead of a cithara in formal public occasions (that is, events organized by the polis and having some degree of religious significance: solo, choral and dramatic contests at the state festivals, music-making at the public religious ceremonies and honouring winners of the Panhellenic games).
All the images of solo lyre-players indicating an agonistic context (Nike, judge, bema) can be interpreted as school (sc. private) competitions.
There seems to be some literary as well as iconographic evidence that a lyre could be used during choral performances. Being lighter and easier to manage than a cithara, the lyre allowed a musician to stride or to dance, which was required for accompanying a chorus. Besides it would possibly be chosen when youths or women were intended to play publicly.
There is no safe proof for the use of a chelys-lyre in dramatic contests. Two characters with lyres represented on the famous Pronomos vase must have used them while composing and staging the tetralogy (or else at a feast celebrating the victory), but not in actual performance.
The insufficient sonority of a lyre could be increased when necessary by using several instruments at once. This is proved by vase-painting, though the occasion for such performances is not clear. [Nina Almazova]