Bloated speakers/weight wise

Aha! Onhwy61 has offered a good explanation as to the workings of my speaker. They have a downward firing bass tunnel running the full height of the cabinet and the size of the aperture facing the floor is quite large. The freedom of the backwave to escape and the direction it goes would perhaps explain why the cabinet neither rocks nor vibrates.
My first post was written before his explanation appeared.

Zaikesman-
Wouldn't it make sense that shorter cone excursion is less apt to cause the rocking tendency you mention?

Hwy-

I think you are correct about the cabinet but I am not sure.
I think 70 lbs. is light in comparison to the behemoths being mentioned here. And the things are over 4 feet tall besides.

The aperture at the bottom is about 4 inches by 9 inches. I don't know how it is configured inside but I would imagine an opening that large would present little resistance and therefore minimal pressure. Is that correct?

My speakers are 50 inches tall and weigh in around 70 lbs. There is a 10.5 inch fullrange driver at the very top of the column firing forward. They sit on a plinth that is 12 inches square with a spike in each corner. They do not resonate. The box doesn't talk or rock. They play very loud. They are 101 db efficient. They seem to contradict much of what has been written here. I think the stability issue may be due to the fact that my driver cannot be seen to move, even at loud volumes because the excursion is very short. It seems logical to me that less pistonic excursion would be less apt to cause the box to move. As for resonance control, I don't know how they do it but there does not seem to be any cabinet activity at all.
All this leads me to conclude that mass is a substitute (and not necessarily an effective one)for innovative engineering.

Line-
I'll have to try your experiment later. I just took a break from painting the living room. The system is dismantled. What I've done so far was just feel it while it was playing. Didn't feel any resonance as I have in other products at times in the past. I concluded that if it wasn't obvious, it wasn't happening. Certainly if you must go to stethoscope extremes to detect resonance, it must be small enough to be overlooked, at least in post-amplification circumstances.