Woofers getting workout, but no bass

Man, sometimes vinyl is a real PITA.

Do you know what is the port tuning? My guess it is between 25 and 35 Hz - otherwise you would not have such a problem even with vinyl, which I agree does tend to have some spurious LF due to the mechanical rotation of the disc once every two seconds...

Pain? Perhaps at times. However, how does it sound to you? Warts and all, it still sounds better to me than any other format.

Madfloyd-
Did you ever get your rumble fixed?

I'd suggest the KAB rumble filter. I had the same problem, and not only it most likely affects the sound adversely, but it might also with time damage the speakers' voice coils since the woofers expand uncontrollably.

At first I thought I noticed a slight difference in sound upon installation of the filter (slight lessening in bloom or thickness perhaps), but now I think the sound is tighter and more detailed. All in all, when you weigh the pros and cons, I'd go with the filter before doing anything else as you have not much to lose but you could possibly benefit significantly. You have a world-class set up; I think you can spend another $160 to possibly get the best out of it.