For me its headphones unless I like what is playing in the shop (we have speakers in FAI connected to the shop speakers with our own volume control. I like hard rock/metal (Disturbed, Korn, Volbeat, Slipknot, ect...)
I work alone in an extremely large cavernous room that houses a Global 20-40-20. I can listen to anything I want at any volume level I can stand at the moment. Frequently music as THis: