Tuning Collars on speaker cables - concept and any good?

That's what I used to think. Then I had an actual symphony conductor over for dinner one night. After drinks he suggested some Stravinsky. Right away he jumps up stop stop STOP! Walks over to the tuning collars, slides them about a half an inch, sits back down, raises his arms in that way- you know one a littler higher than the other- and I cue the arm back down. 

Sure enough, we were sharp, now it was in tune. So they totally work.

Yes some people love to play with new audio toys, especially fancy or esoteric  expensive ones and strain to hear or convince themselves of some meaningful difference so lots of merit there

Somebody has a bad attitude. I won’t mention any names. Have you ever heard of The Little Train that Could? I think I can, I think I can, I think I can... 🚂 Toot! Toot!

Pretty much anything you put around a cable will affect the sound Mike. For good or bad, you can only decide for yourself by listening. That's the way it works.

Back in the day, when Simon Rattle and I used to hang of an afternoon, we listened to his early recording and critiqued them on a Bose Wave that he loved.