Great entry
I really like the speaker idea. It's a very creative way to bring the theme across, by not overdoing it. Since speakers could stand for any kind of popular music the stylized city does its bit and puts the emphasis on Hip Hop.
I especially like how you incorporated the light rays from the typical NG design.
The only tiny piece I could nitpick about is, that the outline of the tankman, that is working on the speaker cables, is a little stronger than on the other tankman. This is setting him apart from the rest of the picture a bit.
Overall an impressive entry. Good luck with the contest!
5/5 & 10/10