Several years ago I attended an Alembic Gathering at the Bag End factory in Chicago. They had some bass speakers there that were, IIRC, about 23". As a guitar player, they scared me off!
And thanks, Harry and Jimmy. Any thread is inherently improved with a Spinal Tap reference. Turn it to 11!
Bill, tgo (who if he hadn't gone to law school might have been a haberdasher)
That was a 4 x 21” cabinet that Bag End designed. If memory serves me they found 21” to be the perfect size for maintaining a tight response.
I do remember bumping a low D and feeling it from my nose to my toes! Talk about going to my happy place. 😄