+1 @uncleang.
How the speaker and the bottom port interacts with the floor is a big factor. I use Auralex Subdude pads under mine on suspended plywood floors but not on solid concrete foundation (finished room with thin dense carpet and pad).
More on the sub bass activator:
https://ohmspeaker.com/news/sba-what-is-sub-bass-and-how-do-you-activate-it/
I bought the SBA circuit a few years back ( not expensive prices for normal people) and installed it to a pair of old Ohm Ls I refurbished myself as well.
How the speaker and the bottom port interacts with the floor is a big factor. I use Auralex Subdude pads under mine on suspended plywood floors but not on solid concrete foundation (finished room with thin dense carpet and pad).
More on the sub bass activator:
https://ohmspeaker.com/news/sba-what-is-sub-bass-and-how-do-you-activate-it/
I bought the SBA circuit a few years back ( not expensive prices for normal people) and installed it to a pair of old Ohm Ls I refurbished myself as well.