Do Beholder Beasts Have ears?

[Beleriphon]

That is actually untrue because the bards ability is his music. it doesnt require casting and is not treated as spell casting. he must captivate an audience first, THEN cast mind affecting spells.

The book does NOT classify a bards music as a SPELL.

So the question is again... Are Beholders deaf?

Given that nothing indicates they are, and can talk, I'd be included to say no.