Cherrybim: I have a Shulchan Aruch (OC 560:3, I think) that says that music is Assur all year round.
DY: If I recall correctly (though I do recall having trouble understanding the T’shuvah, which I probably haven’t seen in a decade now), Igros Moshe YD 2:56 seems to Pasken like the Rama that music is only Assur if one listens to it when he wakes up and goes to sleep.
Git: That is an awful an incorrect attitude. If it’s Muttar, it’s Muttar. Do you shower at all suring Sefira? How could you ever think of showering when you should be in such mourning? Obviously, there are limits. And there is nothing wrong whatsoever in asking and trying to determine those limits. Nihugei Aveilus of Sefira are not even a Din Mid’rabannan. They are inherently very Meikil. You’re not “missing the point” if you try and figure out what the limits are.
That all being said, DY is absolutely correct when he points out that, in general, the Minhag was accepted very, very widely (certainly 20 years ago this was the practice) of not listening to any music during Sefira.