My last job before I retired was as Technical and Quality manager at a contract electronics assembly company. One day we had a potential new customer come in to talk about a new add on his company had designed to reduce the noise floor in top end (most expensive) audio systems. I won't give further details for fear of being sued but it was just total b
s and was not supported by any known law of science. One of the hardest things I ever had to do was to keep a straight face as he explained it.
Remarkably it had been reviewed by a reputable Hi-Fi magazine and given rave reviews.
As one of my old work colleagues used to say "Bull
baffles Brains"
Peter