I'm about a month into being a pinball owner and a week ago my subwoofer quit working on my SST game so I took the plunge to change out all my speakers with a set from pinball pro. I installed all the wires and the new speakers and subwoofer and..... the sound is about the same, also with no bass. All the connectors are snug, everything is grounded and the volume knob on the pinball pro is cranked to the max. In fact with all of the pinsound + dials in the middle, the sound is very low. When I crank them up to the + side, the sound gets louder, but nothing to write home about. It seems like something could be wrong with my CPU/Sound board... Any ideas on things to check?

I figured it out. There is a gap between the pin connectors on the pinsound + for Data East/Sega games. The speaker cable is wiring connector has five spots with the middle spot not being connected to any wires. By lining up the unwired spot on the connector with the gap on the pinsound + board, I now get bass.