so bass traps in corners do nothing, it seems we have been fooled. or are being fooled.

A bass trap....would that be a girdle?

Bass frequencies, once generated, are extremely hard to manage - for turntable feedback, too. Like the video says - it takes a LOT of acoustic material to make a difference. So the tiny little gray or blue "triangle" corner traps (popular a while ago) always made me chuckle. The more substantial corner traps like GIK - yeah they can move the needle "a bit", if you pile them up in 4 corners.

The most significant acoustic change we can make in our systems is optimizations to speaker positioning, listening position, and matching the speaker appropriately to a room. Subwoofer setup too, if you have those. Treating 1st reflection points (for midrange and HF, not bass) is useful, obviously - this can make a significant difference for relatively little material.

I’ve always focused more on the gear, because that’s made the more satisfying and interesting differences to me. When I bring a component over to a buddy’s system (or vice versa), the sonic signature of the component is instantly recognizable and consistent, even in a completely different room & system.

If your system is in a sterile audiophile "shoebox" - just a plain room with nothing but the gear - just as it looks boring, it’s probably also not going to sound great like that. Get some livable stuff in there.

And those tiny little "acoustic resonators" (often sold at very high price) are unlikely to do anything but placebo.

All I know is that four bass traps significantly reduced the reverberation in the room.  

@mulveling Yes indeed, first reflection points (if nothing more) are key. And reflecting on it, Thank you for your many informative posts. 

I want to shave his head.

Don't be so rude to silver haired foxes... I am sorry if mother nature robbed you too soon and left you with nothing but a low WAF bare dome.

(Pretty birds never nest in bare tree...I mean dome.)