Knocking sound from subs

[ExclusiveRA 0]

I have 2 12 inch pioneer champion pro's.  The amp I am running is an hifonics zeus 3000 watt running at 4 ohms.  When the subs are played there is a knocking sound coming from in the box.  I dont think the speaker is blown though because when I put pressure on the back of the box, the knocking sound goes away.  Any ideas?

[smashedz28 110]

Could the box be coming apart? Maybe a loose piece of wood slapping around? Maybe wires inside the box moving around? Check all that stuff first

[nadcicle 77]

Had something similar happen with a cheap prefab. The wood completely separated and split directly in half and was wood slapping against wood and I would start smelling burning. I thought I was frying the sub. Just so happens I was basically rubbing to sticks together and causing a fire with friction lol.

[jonbearsmt 919]

most commonly thats the sound of wood clapping. the box is not glued or  screwed well

[ExclusiveRA 0]

Its a prefab box that I brought over a year ago so I guess its falling apart.  Thanks for the help.

[jonbearsmt 919]

find where its clapping and drive some screws in it  for now