The Big Ben is a great guitar speaker- fat without that icepick-in-the-ear highend when you overdrive the amp.
BTW,the speaker that the Dual Showman amp used was the JBL D-130F series speaker.
These are great for CLEAN, "hi-fi" reproduction on electric pianos, pedal steels, etc. They are HORRIBLE for rock'n'roll guitar that you usually want to overdrive. They are simply too bright and that makes for a very "fizzy" nasty distortion. Ted Weber speakers has a replica of that speaker, and they tell you, pont blank, not to use it with ANYTHING you'll be distorting.