Schofield

Hey everyone, thanks for reading. It's my first post here. I'm audiophile but definitely not an audio equipment expert. I just bought a pair of Cornwall 1s decorators. They were sold as perfect, unmodified condition. They are in amazing condition I would say, given their age. I listened to them prior to sale and they seemed fine. When I listen at home, connected to a new budget level AV receiver (Sony STRDH590), they sound great. That is, except when playing very very low frequencies... the deepest bass sounds in a film, like the epic explosion or thunder, that's really meant to rock you in the chest or rumble your belly. In these moments, there is a tight, flub flub flub, even at moderate volumes (audio file attached). And it's in both speakers. The speakers are placed a foot away from the wall, about 8.5 feet apart. The grills were semi-permanently attached by the original owner using a birch frame that is nailed to the cabinet. They have clearly been well attached and well taken care of. But this means I cannot inspect/report on the driver condition without removing these frames. The back panel can be removed, but I'm not sure what that would reveal. Can anyone diagnose the issue? How serious would the repair be? Advice for further sussing out or reducing the issue? Any help would be much appreciated. I'm very happy with the speakers for music. This specific bass issue is a non-issue for music, since the problematic bass frequency is too low for the tracks I regularly listen to. At the same time, the speakers were not cheap ($2K for the pair). And I hope to slowly build a decent setup around them. Cheers, Fellas. Sam New Recording 5.m4a