Biggest audio hoaxes


Often when people discuss audio, they talk about "snake oil" or "hoaxes."

It's pretty typical to use the term hoax as a tactic against another who disagrees with one, or holds an unusual opinion or vouches for something which has not been verified. That's not what I mean by a "hoax." 

By "hoax" I mean an audio product or claim which has been pretty definitively disproved. Maybe not to everyone's satisfaction, but to common consensus.

So -- with that definition of hoax in mind, what are some of the biggest audiophile hoaxes you've heard of?
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Millercarbon brought up springs again after I asked the forum this question.https://forum.audiogon.com/discussions/what-your-choice-speakers-with-spikes-or-speakers-with-a-vibr...

I was a newbie and was struggling with being nice to Miller or clawing back. I’m still able to post on the website so I guess that means were still friends...? I’m sure if I flew up into the great Northwest to hear his system he would invite me.😀😀

Of course you are invited. Half an hour from SEA in Redmond on Rose Hill where the standard fare is Deschuttes Black Butte Porter with ribs. Rib eye with cabernet sauvignon on request. Come check it out.
@sokogear  has it right.  I tried a Symposium Acoustics Segue ISO platform and rollerblocks for my turntable and was astonished at the improvement.  I have since added rollerblocks for all of my electronic components and also got their Foundation Rack Ultra.  For my new amp on order (should arrive in a few weeks) I also ordered their Ultra Pro Ampstand, Stealth.  Vibration drainage, which is taking the vibration problem out from the component, is THE way to go.  No hoax at all, it works very well. 
@vladtheimpala,
A CD is the name of a slim round plastic silver disc that holds recorded music & allows audiophiles to enjoy "perfect sound forever", when of course they are not listening to the much better sounding slim round (usually black) 12" vinyl discs they were supposed to replace in the 90's.