Spare change on a speaker cabinet

I've got B&W 805 Signatures, and with the curved tops, the coins keep slip slidin' away whenever I try this trick. Guess I should be playing Paul Simon. "A good day ain't got no gain. A bad day's when I lie in bed and think of tweaks that might have been."

If by spare change you mean a 10-pound bag of nickels. Good way to stabilize any speaker or component. I happen to have a bag of lead shot on top of my transport right now. I use these cheapo vinyl auto ashtrays as bags for higher SAF- one has lead shot, the other has 20 silver eagle coins. Had these on my dynaudio monitors before I changed to a full size speaker. Now have on CD player and preamp.

Does it sound better? Maybe I'm not listening hard enough...

Worked for me

Canadian loonies would seem to be the answer. It works even better if they're cryo'd.

My guess is that if it has any effect at all it comes from a metal object vibrating in sympathy with certain musical notes, addin g a sense of high frequency sparkle. There is a company that makes little bells (they call them "resonators") out of precious metals attached to exotic wood blocks. You are supposed to put these in various places around your room to improve imaging. They may very well produce a pleasant effect (never heard a controlled demo, although the manufacturer was going to do one before he got distracted). Maybe a similar effect.
There is no way a couple coins could shift the resonant frequency of a hundred pound cabinet enough to change its damping / ringing properties.