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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Graphene solutions.
I agree that new super materials are used for gimmicks, but there are practical applications for graphene in audio. I'm just about to order a pair of these drivers from Seas... I'm interested in seeing whether the 20-2000Hz claim for an 8" driver delivers in reality, could make for the basis of a great 2 way. In my experience Seas specs are quite down to earth so I'm hopeful.
Graphene in drives makes sense. High strength in the necessary direction compared to weight. It is a good conductor along the grain. It is poor through the grain. That limits it's electrical usage.
I've had speakers with Seas graphene drivers it wasn't used for electrical properties but a corrosion resistant strengthening coating on magnesium cones. 
One that immediately comes to mind is the "$485 Volume Knob" from Silver Rock. The "audio woo woo" factor is off the charts!

"The point here is the micro vibrations created by the volume pots and knobs find their way into the delicate signal path and cause degradation (Bad vibrations equal bad sound). With the signature knobs micro vibrations from the C37 concept of wood, bronze and the lacquer itself compensate for the volume pots and provide (Good Vibrations) our ear/brain combination like to hear…way better sound!!"

Read more: http://bobbyowsinski.blogspot.com/2012/05/485-volume-knob.html#ixzz6uzKWAx1q

That's quite an expensive knob. And boy, what a con job. I'd rather inject Lysol to cure my Covid or shine a UV light on my body.