Is an avel allowed to listen to acapella? Or to rhythm, like drums, without other instruments? Thank you.
It is incorrect for someone in aveilus to listen to a cappella music during aveilus. The reason an avel doesn’t listen to music is not specifically because of the sound of a musically instrument, but because music brings about simcha, which is one of the things an avel doesn’t do during the aveilus year.
The halachos of listening to music during aveilus are similar to listening during sefira and the three weeks. Most poskim do not allow us to listen to a cappella during sefira or the three weeks. See Tzitz Eliezer 15-33(2), Shevet Halevi 8-127(2), Chut Shani shabbos 4 pg. 379, R’ Yisroel Belski zt”l ( see the following link A cappella albums ) R’ S. Miller and R’ Y. Cahen shlita.