Speed of Sound Audio Experts enhance your ride with a Harley Road Glide Audio Upgrade from Speed of Sound Somersworth. Our motorcycle audio experts in New Hampshire specialize in custom Harley-Davidson sound systems with Mobridge Harley integration, ARC Audio DSP, and Sound Digital amps. From Harley 6.5 speakers to 6x9 saddlebag speakers, we deliver powerful, no-splice installs built for performance.