subs knocking

[Arnold55]

so my subs randomly start to knock of beat with the music playing, it almost sounds like a double bass pedal. i have no idea why its doing this. any ideas?

[HHR Ed]

Make a knocking noise, or another bass note?

[Arnold55]

you can tell its not part of the song, the subs will just start making knocking noise but the song will keep going and its like on every song. its hard to explain

[tequila]

stupid suggestion but are the subs (still) screwed down properly?

[Loudcivic]

almost sounds like an rca issue. check all your wiring and make sure everything is tight and no wires are pinched. try un hooking the rcas from the amp and see if it stops. maybe try a different set of rcas. what kind of head unit do you have

[HHR Ed]

A Knocking noise can be the enclosure walls being loose, or as stated above the woofers not screwed down tight, or it can com from the sub itself and may be the dust cap popping off, or spider coming loose, or tinsel leads slapping the back of the cone. Or at high excursion it could be the voice coil rocking and hitting the pole, or bottoming out and hitting the back plate.

So just saying your sub knocks isnt descriptive enough to tell. Gotta get a closer listen and check some of those things off the list.

[Arnold55]

everything is down tight, i think it might be an RCA issue now that you say that, the head unit is a Alpine iDA-X303 and i have had issues with it before to

[speedball1978]

well if you had issues with it before, do you think maybe its the headunit? maybe time for a new one??

[Arnold55]

well its never done that, before it would make all the speakers humm and the music would cut out

[speedball1978]

ok then you might have a defective headunit.. imo get a new one