It's something that we interact in virtually every area of each day. Walk into any store, restaurant, waiting room, and you will hear some sort of music playing in the background. Most everyone has some sort of portable device with which they can listen to their personal playlists. (I have to confess, I'm listening to my Easter mix as I write this.) Music permeates into every facet of our lives in one way or another, because it grabs us and captivates our minds. We interact with it intellectually, emotionally, etc. Music has been scientifically proven to have an affect on every major part of the brain. Yet scientists, primarily those with an evolutionary worldview, don't understand how this developed, since music doesn't pose any sort of evolutionary benefit to humans. They have studied every part of music and remained as baffled as ever on this topic.
So what is it about this distinctive language that captivates us so? I believe that we as Christians have an excellent answer to this question: God created us to create.
Man was made in the image of God. We may have distorted that image, but that does not negate the underlying fact that our nature has its roots in the image of God. We can look all over this earth, as well as the entire universe, and see the immense creativity of this God. And He has injected this creative nature into each of His people. This creativity can take many shapes; for instance, my brother is an incredible visual artist, whereas my creative gifting usually involves having a guitar in my hands.
This creative God somehow has created this language of bringing together multiple melodic instruments to work together in birthing this sound that entices our eardrums. The instruments can interchange (a string quartet, a 50-voice a cappella choir, even a couple electric guitars with one singer and a drum set), but the result tends to be the same. Really, the fact that you can change the scene so seamlessly is also a great testimony to the creativity God has given to humanity. Each person can express their personality and creativity through the music they make/perform/listen to.
There is no "evolutionary" basis for the invention of music, and there doesn't need to be. This is simply another way that we associate with our Creator. Of course, many secular artists don't know this (or at least don't acknowledge it), so that adds a certain amount of pressure on those who make music specifically for the glory of God. We know exactly why music exists, as well as why we desire to make more of it. That should be ample reasoning for us to put our best effort into making the most excellent music that we can. Whether we realize it or not, we are representing our Creator each time we pick up an instrument.
So, as you go about your day, thank God for the gift of music that you hear. God didn't have to create it, but He did for the sake of enjoyment, specifically in our enjoying Him as the great Creator through music.