If I was in the band

I try to meditate 20 minutes per day, and my favorite practice is to slip on a pair of noise cancelling headphones and listen to instrumental music on Pandora.com.  This isn't a traditional meditation practice, but give me one reason it isn't just as valid as sitting in a Lotus position focusing on my breath?

The main thing I like to do when meditating with music is to imagine that music is coming out of me, that I'm creating the sound to express emotions inside of me.  I want to experience the same feelings I would have if I was in the band.  If I was playing the guitar or the piano, and the music is deeply emotional, how would I feel?  I try to imagine that this is real, that sounds of the violin, the guitar, or the sax are coming from my deepest emotions.  I breathe in and breathe out and imagine myself taking in and releasing the sound that I'm hearing.

Of course it's a fantasy.  But I still get something from sucking in the feelings with each inhale and pushing them out with each exhale as if I was on stage.