Could get into a semantics debate, but "woofy," to me anyway, means lots of ringing down in the bass region. A bass "wash," as opposed to tight definition. A quick peek inside such a cab should provide clues as to why it's happening. 1) Pull one driver. 2) Obtain quick peek. 3) Raise index finger in air. 4) Exclaim, "Ah!"
This assumes that the drivers are reasonably well-matched to the cab. If you don't have that, then you can forget the rest.