I agree with Bob. One instant clue to a guitar vs. bass cabinet enclosure is whether the speaker cab is open or closed-back. Guitars often use open-backed speaker cabs, but few (if any??) basses do. I suspect the reason is to reduce the total speaker excursion so the speakers don't over-travel. (I'm probably either over-generalizing or missing the point, but if so I am sure others will clarify.)