The Bible does not directly address the issues of melody, harmony, and rhythm. However, the Bible does deal with the purposes of music: both good and bad. And those who understand music know that it has message and purpose in its melody, harmony, and rhythm. That is, certain kinds of rhythm. etc., say certain kinds of things and this is why musicians use them. I have read secular material that acknowledges this language as an absolute, established fact. So, we need to be careful that our music says the same thing as the words. This is a key in my opposition to most modern "Christian" music. Not only is the message of the words watered down, even when the words are alright, the music is saying something entirely different.
However, people often do not understand the great width of variety within good music. The problem is that modern music is going almost exclusively to the smaller range of bad (I could even say evil) music. Most older folk music, most older classical music, even much of the popular music of two generations ago is not evil in and of itself and can be listened to with pleasure without the sinful connotations. That, of course, does not mean that I would allow it in my church. God's music, in my opinion, should have a certain gravity to it. However, lighter music can certainly be listened to without harm outside the church.
I have found that most Baptists today are not nit picky, but I know I am. I have seen the alternative and it scares me to pieces. I want to bring people back to the grand old hymns. I am looking at several projects that hopefully will help people in this direction. However, for my personal listening I usually listen to classical music. I like it and it is not harmful. I can play it in the background while doing something else. The main reason I do not listen to religious songs most of the time is that the words get in my head and hinder me from thinking about what I am doing--which is usually mentally challenging. Even hymn music without the words brings to mind the words and keeps me from getting the work done I need to do. Often, as now, when I am seriously thinking about something, I turn the music off entirely. But that is just my way.