Please help subwoofer making awful noise

[David Stone]

Hi I have 2 JBL 15's in a 7 cubic ft ported enclosure powered by a Rockford r5001x. The one sub is making a distorted noise almost like the box is resonating badly. Only at high volumes. Maybe around 35 and up on my pioneer deck. I pulled the sub and it does not make any noise free air but as soon as I drop it into the enclosure the noise starts again. My braces seem to be strong and the port has not come unglued. Could it be the sub and it only happens when there is pressure behind it from the enclosure? It started one day when I was pushing them pretty hard. The spider and cone seemed to be attached and there is no noise when i push down on the cone. Any suggestions would be appreciated.

Thanks

[SIDE SHOW]

Make sure it's not your wiring going into the sub flapping around in the box, and try pushing or holding some panels and make sure it is actually the sub making the noise not just a plastic trim piece flapping around. another thing to try would be to swap the two subs over, and see if the same sub is still making a noise or if the noise is still coming from the same side

[SnowDrifter]

What do you mean distorted noise? Is it a sharp banging like if you hit some pieces of 2x4 together?

[David Stone]

The noise is kind of resonating with the note Almost like the trunk of a car would when the bass hits. But I cannot pinpoint where it is coming from. It sounds like the whole baffel is making the noise. When I pull the one sub it sounds fine free air and the sub that is still in the box sounds fine but as soon as it seals into the box the noise starts again. It is not subtle at all. I like the idea of swapping the subs. I have even tried to unplug one sub at a time from the amp and it still made the noise. I may have to build a new box but I hate that idea if they will just do the same when I do that. The thing is I don't know which sub is causing the noise. It may be the second sub reactiong to the first when it seals up. I guess I have to pull them both next weekend.

It is a royal pain having to work in my truck because it is still like 106 outside here in Phoenix.

If I pull them both and they don't seem to have problems free air then I guess it is safe to assume the enclosure is the problem?

[SIDE SHOW]

try swap the left and right rca's over on your sub amp and see if the noise changes, might be a signal problem

also check and re-check your wiring inside your box and the amp going to the sub.

[David Stone]

Good idea I will give that a shot tonight. Thanks.

[David Stone]

Yeah it was the same noise when I swapped the RCA's. I am going to have to pull both subs this weekend. Maybe pull the box and inspect all of it.

[SIDE SHOW]

Same noise from the same side? or did the noise change sides?

[Broke_Audio_Addict]

Pics of the enclosure/ design may help us help you.

[David Stone]

https://www.flickr.com/photos/134243985@N03/18972311818/in/datetaken/

This gallery has the whole build on it. I used gorilla glue and drywall screws. They are JBL GT5-15's.

It is weird it was not making the noise on the way to work in the morning but it was making it on the way home today and yesterday. Do you guys think the heat inside my truck would affect anything? I tried one RCA at a time and swapped both and tried them at the same time. It is just weird that it does not happen all the time.

I am having a hard time pin pointing if the noise. It seems like it is coming from the top of the box in general and I cannot tell if it is one sub or the other. But when i pull the one sub out and set it on top of the box free air it seems to play fine. In fact they both seem to play fine excursion wise and both seem in phase.