Originally Posted by Bass_Pounder
Are you properly modeling with cab design software and retrofitting the cab to the speakers, or are you just swapping out speakers?
I would guess a bit of both. I'm sort of building a retro rig consisting of a Fender Studio Bass amp section built into a head and the old Peavey 2x15 cabinet. I got the cab for almost nothing, & I had the speakers, so I loaded them up. The best I could measure the shelf porting, it was wrong for the T/S parameters of the drivers. It sounded like it, too.
The shelf port was going to be almost impossible to modify, so I thought I would try sealing up each compartment. That more or less eliminates cabinet tuning and is much more forgiving; as long as the cabinet volume isn't too small or way too big, the speaker does its thing. Each compartment of the cabinet is 3.18 cu. ft. which is not optimum, but within the range for the T/S parameters of the drivers. The cabinet performance is greatly improved, but then I noticed the opposite drift in the drivers when allowing a long sustained note while searching for "air leaks".
I think I discovered the issue. Even though the two drivers are identical, one has been re-coned. When I swap their position in the cabinet, each driver continues to act the same, eliminating the cabinet as the cause. Perhaps the re-coned VC winding starts on the VC former at the opposite end from the original? Not sure on that, no way to tell.
There doesn't seem to be any phase canceling, so I'm going with it. The sealed cabinet does wonders to tighten up the low end when using the tube amp. It was sloppy when driving the cabinet with the tube amp when the cab was still ported, which is why I started this journey.....