A couple good points have been raised. One is that if a hymn book has already been approved by the Elders then the picking of the songs is already fairly delegated. But the matching point is that the songs normally are meant to complement the sermon, so why would a woman be involved in picking them on a normal, practical level?
In my church, the pastor has delegated that responsibility to me, because he admits he is almost clueless when it comes to choosing music, though from time to time he tells me he wants us to sing a particular hymn.
When it comes to music complimenting the sermon, the pastor tells me what passage of Scripture he is preaching each week, and I spend a lot of time in prayer and Bible study on my own before I choose the music. Then I send him a list of the songs and the words for his approval. This works well, and it is unusual when the music and sermon do not compliment one another.