I know we don’t listen to music during the Three Weeks and Sefirah, as well as mourners. What about a cappella? Some groups even use their voices to mimic instrumentation, and I can hardly tell I’m not listening to the real thing.
The Aish Rabbi Replies:
I’ll begin by writing that the classical sources on Jewish law never mention a custom not to listen to music per se during the Three Weeks. What is actually mentioned is dancing (Mishna Berurah 551:16), or more broadly, any activity which brings a thrilling or uplifting sense of joy (R. Yisrael Belsky). More recent authorities include music, even recorded music, under this general heading.
As a result of this, many contemporary rabbis are not that excited with the recent proliferation of “kosher mourning” a cappella CDs, consisting of magnificently orchestrated and sometimes digitally-enhanced human voices. Even if all the sounds are technically human-generated, if the listener practically cannot tell the difference between it and instrumental music, I would definitely stay away from it. (Authorities state further that if the a cappella consists of digitally-modified sounds, even if they began as human voices, then we consider it identical to band music.)
However, if the music consists of plain human voices – even if the harmonies sound very nice – there is much more room to be lenient. This is especially so for women who listen to such music so that they can remain calm and relaxed. (Sources: Tzitz Eliezer XV 33, Shevet HaLevi II 57:2; VI 69; VIII 127).
Note that this ruling applies equally to the Three Weeks, Sefirat Ha’Omer and when one is in mourning.