From My Speaker Modification Notebook
On Feb. 15, 1990, I called Polk Audio and asked to speak to someone concerning modifying my SDA-1B speakers.
The fellow I spoke to, Chris, recommended the following changes:
1. Apply foam tape to all the speaker baskets to reduce ringing.
2. Replace mylar and electrolytic capacitors with polypropylene capacitors.
3. Jump (short circuit) the tweeter protection capacitor or replace it with a polypropylene capacitor.
Chris recommended that I NOT do the following:
1. Don't replace the drivers because they were carefully and specifically chosen to sonically blend in with each other.
2. Don't replace the internal wiring because (a) the distances are so short that you won't notice a difference and (b)thicker wire could cause the printed circuit traces on the crossover circuit board to lift off.