I really like the voice of the shopkeeper. Is there any way in Crypt of the Necrodancer to always have the shopkeeper's voice regardless of the distance from him?
You can download the shopkeeper version of songs, and use them as custom songs in the game (example). Unfortunately if you're going for high scores, this will put you in a separate category.
There is no way to have the shopkeeper's voice permanently without custom music. If you're far away from him, he will get quieter- that is something that is hardcoded into the game.