Hi,
for me, the point is not getting more Boom, but extending frequency range.
And for that it doesn't matter if ou are using subs or full range speakers.
Many instruments show some amount of very low frequencies (e.g. wehen strings ar plucked, drums are beaten etc.), and several larger concert halls have modes at low frequencies (The Vienna Musikverein @ 21 Hz).
This means that the room interferes with those low fequencies.
If they are missing, because the setup cannot go that low, the music will sound flat, not spaceous.
An important thing here is that the listening room needs to have a good (dry) bass response.
If that is not the case, any sub oder fullrange speaker willsound boomy, which is awful.
Cheers
Babak