Not really a building question, but just curious.. I know in wood boxes with no vent, you need a spitter or your speakers will beat off each other an.. well it ain't good... So why don't fiberglass boxes need splitters? I've seen boxes with 3 or 4 open spaces for 10's or 12's with no splitter.. How does this work exactly?
That is correct... you do not need to separate the woofers. The woofers are seeing an identical signal so can share the chamber.
the only reason subs would affect each other in an open chamber is if the polarities are reversed on one vs the other(s). Think about this.. say there are 2 identical subs and one is displacing volume out while the other is displacing the same volume in. net volume displacement is 0. However if they are both displacing in the same direction... you have displaced 2x the volume of one sub. Hence 2x audio output.
