[HunterM]

I heard Hamza Yusuf say in one of his talks that he thought some of the music today has its roots in the Muslim chanting of La ila ha ilalah for example. He was not saying that it is halal. Music can have a profound effect on the human heart it can make us joyus and it can make us weep and anywhere in between. I have also heard that some scholars had music theories ( beats or rhythms written by them to specifically bring about certain changes in the state of the audience or singers), used to improve people.

Sensitive people can detect in the music the inner state of the musician which is conveyed in the music. If the musician is a unbeliever and has the inner condition of kufr this is conveyed to the people who listen to their music creating bad emotions in the people who listen to it. And if they are good it bring peace and healing to the soul. So one should be careful who you listen to if you do not want to be adversely affected.