I’ve spent a few months putting together a system in a 121/2x23x10’ room. I added a pair of REL S/812 to a speaker that covered all but the lowest octave. My subs cross over around 25-30hz and volume is set to 1/4 of full volume and my phono cartridge was not liking the bass. I moved everything to seven different locations, but no luck. I’ve got a hardwood floor with a thick pad carpet, but the room is suspended over a two car garage..so lots of issues with bass. So far my solution is bass traps..nine large bass traps, Tiger Maple rack with 3" thick shelves..plus 3" turntable isolation stand with a 108 pound integrated Amp on the bottom shelf. Also, I added a full size low back sofa.
My main speakers are Sabrina X and yes, the subs make a difference.