Pinball Pro is a family owned and operated business located in Nebraska. Our claim to fame is our pinball and arcade speaker / sound upgrades! We stock new pinball machines, pinball machine upgrade and accessories, new arcade games, and arcade game parts and accessories. Full speaker upgrade kit for Williams WPC-89 Pinball Machines. This sub-woofer extends bass reproduction to 32 Hz. No permanent modification is required to the pinball machine. The special design of the subwoofer network routes the low frequencies to the subwoofer, and the full spectrum of sound to the backbox ...