In short, yes and yes. I went from floor-standing speakers rated to go down to 30 Hz, to large stand-mount speakers that go to 40Hz (2x9-inch woofers in each sealed box). I then added two subs made by the same manufacturer.
The bass from my current system is far superior to what I had with the floor-mounted speakers because the sealed box provides more detailed bass down to the ballpark of 40Hz and the dual subs get to 20Hz with impact. This combination loads the room much better and the subs have a remote control so I can quickly add +1 or +2 or take away -1 or -2 to adjust the bass response for the volume I happen to be listening at and for the music I am listening to. IME, it is hard for a single speaker to cover the entire frequency range and do justice to the bass. Not saying it can’t be done but rather that is is not always done well.
I would like to add a third or fourth sub and would also like to run my main speakers through a high-pass filter (at 40-45Hz) so the amps and speakers do not need to work so hard on the low end. Fortunately, as recommended by the manufacturer, the speakers sound good rolled off naturally below 40Hz, my amps have the power to drive them without working too hard, and it was fairly easy to integrate the subs at that frequency. If not done in the digital realm, the trade-off of using a filter is comparing the benefits resulting from requiring less effort of the amplifiers and main speakers against the detriments with respect to what it does to the sound of the signal above the high-pass point.
