how do u know when u have a standing wave problem? on some notes i hear a rattling comming from the box? is that a stand wave problem.??
A standing wave eats up output of your subwoofer, it is usually most noticable as a lack of bass response or the sub being hung up on itself. Clap your hands together and you'll get the idea. A rattling from the box can be many things...
(1) speaker wires rattling against the box
(2) sub is loose and is rattling against the box
(3) The box is rattling - box not built strong enough
(4) the box is rattling - not mounted properly
Your problem seems as you state only at specific frequencies, keep playing those frequencies over and over again while you work with the box, try things like mount the box on foam, does the rattle go away, if so it may be mount related. Check the speaker wires inside to make sure you don't have an extra 4 feet of wire in there. Anyways go from there and see what you find.
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Top Secret, I can tell you but then my wife will kill me.
Forbidden is correct. It could be any of the 4 things he discribed. Standing waves in sub boxes are few and far between, as the wave lengths involed are too long to develope in a small box. As long as you are not trying to cross your sub over too high you should not have standing waves.it sounds for sure something is resonating. you can use a sweep to get an idea of where these anomilies occur. and help track down why.
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Steve@A.E.S