However good they are I think your box subs would just swamp the IB with distortion.
It's never just about playing low frequencies. You can do that many different ways.
SVS subs can do it superbly and impressively in huge quantities for films.
What IBs are about is very low distortion
and extension.
What you hear for the first time in your life from a loudspeaker is the fundamental without the usual harmonic hangers-on who will never leave the party.
It is instantly recognisable on drums, organs, electric and double bass.
You know immediately that something is very different and obviously right.
It's not just about the new sense of foundation, authority and depth that you've never heard before.
It's about realistic leading edges and decay without the usual mud and mush you never knew you had. At all levels too! Not just when things get loud.
You can hear a gentle drum on a quiet folk track and it sounds like its roots go as deep as a coal mine and it is surrounded in pitch darkness.
Get yourself a home demo from an owner of an IB with at least 4 x 15" drivers and hear the clear difference for yourself.
Then use at least 8 x 15" drivers when you build your own IB and cross over to your speakers at 80Hz. You don't want to deliberately introduce harmonics which aren't produced by the IB, do you?
Thomas will advise if you ask him nicely. Just don't say I sent you and you'll probably be okay.
