i had the graham ls59 for about 8 month in my room and they do decent bass.
when i speak about hifi i mean comparing good driver vs good drivers. when it comes to bass its the one thing that is really not complex, a good 12” or 15” absolutely destroy a 8 inch for bass.
however, a 15 /12 inch needs a totally different speaker desing: ie implemented into a 3 way, or crossed to a horn for a 2 way and that brings a very different sound or set of compromise then a bbc 2 way. just integrating a 12/15 to a midrange around 300hz is often audible, or a horn have its own set of compromise in terms of coloration. i find that at about 8 inch, it can start to give satisfactory bass. never heard a 6,5 inch do bass without obvious serious limitations/coloration/distortion
Bass reproduction and associated tastes are a funny thing. For some, it's an absolute necessity for it be a visceral, invigorating experience. But then, I can listen near-field to 5 inch cones and not feel left wanting for anything. It's illusory, but it just works. Same with IEM's. Perhaps something to do with being more of the headphone generation...
I'll be damned, but I'll take a quality experience every time. If you're fortunate to get both (ie with necessary quantity too, with multiple subs and flat in room response), it seems you're likely American!
Enough seems to work ok for me...I imagine the 5/9's would appease me nicely.