More or less. In the data sheet measurements you're seeing the LF gain from a large (roughly equivalent to IEC, differences are detail only) test baffle of basically the same dimensions as Seas used up until about '03. So in practice, when normal baffles are in play, the response is automatically somewhat different. The box load here does reshape a decent portion of the BW < 400Hz; not all of course, but it's functional over a broader BW than most vented alignments (to just over 200Hz). The modest null around that frequency is real; you do get, like most multi-chamber loads, some cancellation at the top of its passband, although this will in practice be dominated by most room modes etc. I'm not claiming (or suggesting) this is perfect, but it has its interesting characteristics and makes for a decent, slightly 'different' load to the usual run.
