Is one allowed to listen to music during aveilut after the shloshim for therapeutic porpuses?
Is there any difference between the way ashkenazim and sephardim hold?
According to this article the prohibition against listening to music is regarding music that causes joy or leads to dancing. Thus, one may listen to classical, slow, chazzanut, or similar music.
Refer to the article for its sources and additional information.
Attending a wedding, in particular, has separate problems besides just the music aspect. Likewise, one should not attend public events such as concerts even if it is a classical concert. I'll try to link in a previous M.Y. question that addresses this area. Someone asked this recently.