Rav Eliezer Melamed, the rav of Har Bracha and the rosh yeshiva of Yeshivat Har Bracha, has issued a psak that is making waves. It is only making waves, I think, because of our current societal culture that looks publicly for only chumros and rejects anything that might be taken as a leniency, at least in public psak.

The psak he is publishing says that during sefiras ha'omer normally there is a custom to prohibit the listening of music. Rav Melamed says that when a person is driving and needs something to help him stay awake at the wheel, he is allowed to listen to music to keep him alert.

Rav Melamed adds that this only applies in such situations, but outside of the car it is prohibited to listen to all music, be it live music or be it recorded music, while acapella music can be listened to.

The psak is not necessarily revolutionary, and is not even such a leniency. It makes sense as if one is tired while driving he should do whatever is necessary to keep himself awake and alert, and might be considered pikuach nefesh. There are far more lenient piskei halacha regarding listening to music during sefira, from digital recordings and the like, for a variety of reasons. The shulchan aruch does not even mention the prohibition of listening to music, though it does prohibit weddings and the commentaries talk about the simcha and dancing. The custom has become common to prohibit music even outside of weddings and parties, though the customs vary as to when and what types of music must be avoided.