Put a very large capacitor in series with the speaker, where one of the
speaker wires connects. The goal is to move the entire frequency response up
or down without using any shunts or parallel components. You might take the
speaker apart and glue all the joints, and inspect for anything that might
vibrate or move inside.

From:
Date: Sun, 16 Jul 2006 23:20:22 GMT
Lines: 38

I have the opposite problem, my computer speakers buzz when I play some
modern movies with music in them (Walk The Line (Johnny Cash)). The bass is
boosted because I guess "everybody has a home theater system with a
crossover and floor-shaker sub-woofer". Well I don't and can't afford one
because my debtors can't give me anything but static. If any of your
experiments cut the bass please tell me in the group.

--
dgm