Did you watch/listen to the comparison video above I was referencing in my comment?
Yes, in the "before" there was a flutter echo which 100000 million percent HAD TO GO in order to do anything you would really want to keep. This isn't normally the target of low band absorbers, but they most certainly can adress it. In the picture I showed of my room, we actually had substantial flutter echo in that room which could even cause feedback when the room was used as rehearsal space. Those panels killed it.
In my case though, at around 20% coverage the room is still quite live, but
and here is the big part people seem to keep overlooking
it is live generally for the same length across the entire audio spectrum. Its a rather large room so its kind of cheating, but there it is
It is not, unlike the examples given or especially vocal booths, live across the whole bottom and mid but a bit (or a lot) dead in the highs
Maybe it is hard to tell over Youtube and just video alone.... but I appreciate (like Bruce said) a little
more "bounce" in a room one is tracking in, versus treating that room to the point that there is little
to any duration in the sound of whatever instrument is being used.
I do like some bounce as well, but I don't think you have ever heard, and for sure its in NONE of these sorts of videos, a room that has "little to any duration in the sound of whatever instrument is being used"
This video, and all the others, sometimes show an end to duration in the higher frequencies, but the low mud is still bouncing around there for weeks