Hilchos Sefiras Ha’omer – 15

1. During the days of Sefiras Ha’omerit is forbidden to arrange and participate in dances of various sorts (Shulchan Aruch and Mishnah 493). The custom is to also not listen to musical instruments at all, not even recorded music (Igros Moshe III:87).

2. A music instructor who earns his livelihood by playing instruments is permitted to play them during the period of Sefiras Ha’omer. But if he is playing them for his own enjoyment, it is forbidden (ibid.).