I don't think so.
FWIW, I found the rear speakers are actually a bit closer to the riders ears when kicked back than the fronts (with no passenger), and got a bit better sound fading the back up slightly. I am all stock on the radio/speakers (except satellite).
Stock speakers and if you don't have an amp....I must be deaf! Lol. I can hear it from parked to 30-40 mph but at speed no way! I don't think I've ever had any radio that couldn't balance from left to right!
Jess you must have OEM pipes?
Thanks for all your help!!

Yeah pure OE pipes (except Airflow tips) on one, and cut pigs and tips on the other (supervalk, with front speakers only). The music could be better quality, but it's OK. I should run earbuds, but I hate dangling wires. What's getting on my nerves now is my sat radio plugs seem to be getting loose; an old Roady XT, but installed new last year.
I ride with some guys with new bikes and audio, and to pull up next to them, theirs drowns mine out completely.
I understand in a car where you may want the rights a bit louder, but on a bike the only reason I could see for balance is if you have one ear hearing loss (or one ear plug LOL).