# Possible blown sub



## gilbypoleadamson (Feb 8, 2007)

So Im not totally sure what a blown sub sounds like but I hope I didnt blow mine and its just something else Ive over looked. I built a sub with help from these forums about a year ago and its been great since. Thursday night I was having a party at my house and bumping some loud dubstep and everything was going good and the bass sounded great then today I fire up some Revocation, a metal band with lots of double bass, and I start getting this weird noise that sounds like something is hitting something else in my sub. I did some tests with other music, more dubstep and the deep bass still sound great then every once in a while I would get the same weird hitting sound. I did some bass sweeps and it didnt sound any different. My sub is a CSS Trio 12 with a Bash 300 amp in a ported box. Please tell me my sub isnt blown, and if it is is it possible to fix it? or get it repaired or is it a lost cause now....


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## GranteedEV (Aug 8, 2010)

The mechanical noise you describe sounds vaguely like bottoming out, which can happen, indeed with vented boxes. The two contributors to this would be

- too low a vent tune (bottoming above tuning point) 
- too shallow or low-centered a high pass filter (bottoming below tuning point)

When you hear the sound, how much motion are you getting from the woofer?


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## Guest (May 15, 2011)

It could have just been port noise too. Might have been the amp clipping. Who knows.

Is it fine at lower levels?


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## gilbypoleadamson (Feb 8, 2007)

Ill make a video of the noise because its hard to explain, the reason why i bring it up is because i neevr heard it before a couple days ago when i was playing it louder then normal


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## GranteedEV (Aug 8, 2010)

gilbypoleadamson said:


> Ill make a video of the noise because its hard to explain, the reason why i bring it up is because i neevr heard it before a couple days ago when i was playing it louder then normal


That doesn't sound like a good idea.

If my hypothesis is correct, then your issue is frequency and SPL dependant (IE the recording you've been using). While it is a good driver, it doesn't have the most xmax in the world If it is in fact bottoming, you don't want to damage it!

Let's try to tackle the problem in a way where any tests you do WON'T produce the mechanical noise.


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## Moonfly (Aug 1, 2008)

I agree it sounds like bottoming out. In simple terms, that is simply caused by the sub reaching its mechanical limits. In the short term, the simple fix is dont push it so hard. If you need more performance, then you need to examine the design of your sub. Did you model it in WinISD, or have an original build thread on here we can take a look at?


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## gilbypoleadamson (Feb 8, 2007)

Yea I got alot of help from people in the forum for the design, http://www.hometheatershack.com/forums/diy-subwoofers-general-discussion/18316-new-sub.html theres the design thread, the thing is that it never sounded like that before I turned it up but it still makes smooth deep bass but only makes the thudding/thumping sound at the higher freq. My one friend who also builds subs came over and listened to it and said it sounded like it was bottoming out probably because i need to re-caulk the inside and that there is an air leak. I guess its possible I just blew a hole in it or something and now its bottoming out because of that. Up until yesterday I had never heard it make that noise before.


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## gilbypoleadamson (Feb 8, 2007)

Not sure if this will tell you guys much but heres a quick video I made from my phone of the noise its making, the song is Seven Nation Army by The White Stripes and just my sub is on, I never got around to doing any sort of paint or carpeting but its always worked great, if its blown I might just have to go make a new one...


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## Moonfly (Aug 1, 2008)

Sounds like it might also be something simple like a cable coming into contact with the rear of the driver, which isnt actually that uncommon. I would remove the driver and inspect it, then move on from there.


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## gilbypoleadamson (Feb 8, 2007)

I did and couldnt find any problems with the amount of space, especially since its never made that noise before. I took both the amp out and felt in there for something moving and took the sub out and looked at it but I dont know enough to be able to tell what could be wrong just by looking but it looked like it always did, nothing obviously bent or broken


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## tundraSQ (Mar 17, 2007)

tinsel slap?? play the sub in free air....holding it in your hands and take a video...


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## nht1259 (Nov 24, 2010)

Maybe the cone has separated from the spider. Don't ask how I know what that sounds like...


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## bensl (Nov 18, 2008)

nht1259 said:


> Maybe the cone has separated from the spider. Don't ask how I know what that sounds like...


yep i was going to suggest that too. remove the driver and have a look.

been there - done that...:doh:


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## killa12222 (Jun 8, 2011)

Sounds like a loose panel inside/outside the enclosure?


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## dougc (Dec 19, 2009)

Could be that the sub needs to be screwed down tighter with new gasket foam. My sub did this when I recently replaced it. It sounded like a piece of something plastic was vibrating. New gasket tape and a tight fit fixed it.


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