I've tripped on DMT several times, and have done it lots of times with and without music. Listening to it without music is almost like a new experience. You can focus on the "static" noises that encompasses you more, and I feel that it also gives your brain more of a chance to wander and see where the trip actually takes you. This one time i did it in complete silence in my backyard and the first noise i heard was an owl screech about half way through the trip. It definitely made me jump a little lol, and it tripped me out pretty hard.
Listening to music while tripping on DMT is more of a soothing experience. It's kind of just something to relax you a little bit, and give you less of an uncomfortable feeling of isolation.
There's a time and a place for both though. If i listen to music, i usually put on some trance or dubstep. the music isn't too important since you can never really concentrate on it anyway, and it's almost like you don't even notice it if you took a huge hit of DMT. Most of my trips involve music though, just because i have a tendency to get paranoid easily.
edit: i got 2 doses of DMT left, and my next 2 trips are definitely going to be without music, and in nature. I feel like outdoor trips are much more meaningful, and the visuals that can be produced from a scenic view are quite incredible.