when i brought my sub back one of the installers told me to put the infrasonic filter on like 20 hz in a sealed box.. i know for ported boxes its very important but what does it do for a sealed box?
"i know for ported boxes its very important but what does it do for a sealed box?" Nothing. With a sealed box, you still have control over the sub even at subsonic levels, a sealed box can play flat to around 9hz in a car. You don't need to use an infrasonic filter with sealed.