What is the Eariest Source? - Listening to Music During Sefirah

Originally published 5/6/11, 11:40 am.
We all KNOW it's ASSUR

Or is it?

Music During Sefira | Hirhurim – Torah Musings

Questions:
A. Could Yom Ho'atzmaut be exempted from this prohibition?

B. Could Yom Yerushalayim be exempted?

C. What about s'machot such as Bar Mitzvah or a Brit Milah?

Shalom,
RRW