Sound like it would be much cheaper to just replace a few warped records with new copies which will probably sound better anyway.
Easier said than done when you've been collecting records for 45 years as I have.
I observed first hand today another benefit of using a clamp/ring on my rig today. I put on an old pressing of Chick Corea "Song of Singing" that's I've had for decades. I was doing a sound check pre cleaning and played the start at higher volume than I normal listen. I noticed my paid of subs with excessive excursion at the lead-in groove and beginning of play. After I added my 5+ lbs. of clamp and outer ring and started play again, the woofer pumping disappeared completely. The tight coupling of the disc to the POM platter certainly seems to help with LF stability.
