why does my sub sound like a jackhammer?

[Problematic]

Got this old diamond d3 I've had laying around forever that I'm not sure what went wrong with it. For example, playing a 20hz sine wave makes it sounds like a jackhammer. Something is rattling/knocking inside. I guess it sounds like the coil bottoming out kinda, but it varies with speed.

Both coils are good at 3.4 ohm.

Any ideas?

Btw makes the knocking noise if you tap the cone also. I don't think its the dust cap either, but could be wrong.

[Phaeton]

those coils are reading a interesting number.

[Problematic]

Coils are 3.4 separate and 1.8 wired in parallel.

I thought that was about right for dual 4 ohm?

[Noel989]

That might be the sound of the sub bottoming out or that's how that frequency sounds

We need more details

Type of box

Amp

I'm assuming just 1sub right?

[Problematic]

The noise occurs as frequently as the sub moves up and down. Subs barely moving and makes the rattle. The louder you crank it, the louder the rattle gets. Rattles at very low volume also. I just tested it free air on a couple songs and on sine waves. Its definately the sub making the noise.

I'm guessing that i overheated the sub and something inside has come unglued. I'm just not quite sure what. Could be the voice coil former from the sound of it. It's a metallic clicking or rattle sound.

I'm pretty sure it's not voice coil rubbing in the gap either. It's not scratchy sounding

I've heard someone else's sub sound like this before once, but they didn't know what it was either.

Could it be tinsel leads?

It doesn't really help that i can't see any of the inner workings of the sub. Not much for heat ventilation other than 4 little holes on the backside of the cone around the coil and a vented back plate. You get what you pay for i guess.

Just the one sub

On my rockford t1000bdcp.

[RainStryke]

I've had that after a sub recone... My glue didn't take on the spider and it was allowing the voice coil to go too far up and it was rubbing against the post. You probably need to recone that subwoofer.

[Dan2427]

I have had a RCA that got pinched and ended up wearing through and did that.

[Problematic]

It definately needs reconed.

As far as reconing goes, what are my options?

I'm not sure if this sub is even worth it. Depends on cost and what all i can do to it. Sub is a Diamond audio 15"d3 4 ohm dvc

A recone would be fun to do though considering I've never done it before and would like to learn how.

[Problematic]

I have had a RCA that got pinched and ended up wearing through and did that.

My other sub (diamond hex pro) doesn't make the same noise though. Hooked up on exact same amp and wiring.

You can even tap on the cone with everything unhooked from the sub and it does it

[RainStryke]

You can try contacting the manufacture and see if they have recone kits. That's what I ended up doing with my digital designs subwoofer... The lower end subs don't cost much to recone... My kit was 35 dollars, plus $20 for the glue. Not sure if you will get anything like that through diamond though.