Hey, well I just bought a pair of slightly used Infinity 12'' 1250w subs. Now the only problem was that the owner said that the dust cap was kinda loose, and you heard a bit of a raddle.
Now, when looking at it, it does not visually look loose, but say you push the cone up and down, you can hear it. If I apply a bit of pressure on the back side, then do the same thing, the sound is gone. It sounds like the dust cap, is loose, like the middle of if.
What would be the best way to repair it ?
Thanks

 

sounds more like a coil than the dust cap... if you're putting pressure on it and pushing down, and the niose is still there, then how is it rattling?

Mark

 

You can take it out of the box and determine where the sound comes out of. If it's from the front, then might be dustcap, if it's from the inside..
I had a dustcap rattling on one of my subs and I got confused first. But it's easy to spot the dustcap that's even partly off. I used some vibration-friendly glue from Home Depot, forgot the name, kinda like silicon.

 

If it sounds like a scratching noise from inside the sub, then the coil is scraping on the magnet and the speaker is toast. That's how you test a speaker before you buy it, push the come to max excursion in both directions. If it's silent, it might be a good speaker, if it makes noise, gently hand it back to the seller and walk away.

 

"If I apply a bit of pressure on the back side, then do the same thing, the sound is gone"

I would assume it's not in a box, or it was taken out.

Mark

 

I think it may be the coil rubbing the magenet.
What causes this. ? And is there any fix ?

 

I wouldn't buy used speakers. The only time i've sold speakers, i hooked them up so the buyer could hear and see that they work.