Bottom line is with very rare exceptions Japanese speakers of that era just aren't built to put out much low bass and I am pretty sure you have bottomed out those Pioneer woofers and they are toast. If you want to listen to loud bassy rock and roll get some Radio Shack Mach Ones, Cerwin Vegas, or large JBL bookshelf speakers. The JBLs will sound better on the top end but are more coin., hook them up to your higher watt Marantz wire in a sub like Yamaha powered sub from a pawn shop and call it a day.