I personally believe that music is ike a languge.You are not gonna get a person who speaks spanish to understand the Bible iun english,and a person who speaks spanish is not gonna be able to tell a english person about it.You are not gonna get the word or God to heavy metalers wit soft,acoustic song like Selah,or Casting Crowns,but if you get some band like As I lay dying(not saying their metal)they are gonna listen,and take it in,and the same with a country or acoustic kinda person,a guy who likes kenny chesney is'nt gonna like someone like Subeseven,or Underoath,and a person who like Underoath and such is not gonna listen to like Randy Travis,or like a christian country artist.I also think if you music is truly "clean" like no bad words,or things like I hate this or that,or cutting wrist or such,it good.I also believe things with beat can be Godly,I mean alot or things in the Bible time had beat.So if you have doubts about your music,then don't think twice,you should know if there is doubt,there is a reason for a doubt,and I'm sure if theres a reasong it's a bad one if it makes you wonder if the bands means it bad or not.Just like if you have a doubt about being saved,you should probly get reasurance.Look at the artist too,see if he is living a Godly life,make sure the person is not singing one thing,and doing another. P.S.Sorry for the grammer if there is any,I'm not that good at it.