Rav Belsky shlita paskins that Capella is not permitted during availus, 3 weeks or sefira. That applies if one is listening for musical enjoyment.
Rav Shlomo Zalman Auerbach ztl said that even vocal singing takes on a din of music once it is recorded. A layer has a din of an instrument. However poskim permit music when driving IF IT IS needed to keep the driver awake. (There are other better ways. Drashos of Rabbis Frand, Krohn, Wachasman…….) But if you need music to keep you awake while driving , maybe you should pull over and take a nap.