View Full Version : How do you tell if you have a blown subwoofer
saprano 09-29-08, 11:15 PM I was watching war of the worlds today and the scene where the pod steps out the ground my sub started to rattle. its a very bass strong movie with hz getting down into the teens, so i put somthing heavy on top to make it stop. i played the same scene again and it did stop, but now the weight that i put on there started to rattle.so i took it off and played the same scene again but this time there was no rattle and i noticed the bass seemed weaker. me being worried i played some other movies, and i still noticed a weaker bass. its strong just as strong as before. did i break something? me playing that scene over, and over was that a bad thing? Then i tried playing a bass heavy music track with my mains un plugged, i could hear the bass but very very little was coming through. it was like the bass was stuck inside, i dont think its all in my head cause i definitely notice something different......could it be the protection circuitry? damaged coil?its a definitive technology pro sub 1000 10" 300 watts.
Hurtful Goat 09-29-08, 11:44 PM Protection circuitry generally just shuts the amp off. So that isn't it.
The common symptoms of a blown subwoofer driver:
-Unusually weak output (aka sensitivity goes to crap)
-Rattling sound (almost as if the driver is bottoming out at next to nothing)
-No output at all
-Cone or surround are torn or ripped away from the basket or each other (If you can pull the driver, inspect the spider for the same kinds of damage)
I may have missed a few. A damaged (burnt or maybe scuffed) voice coil is a form of "blowing" the driver, I believe (anyone want to chime in on that one?)
JBLsound4645 09-30-08, 05:53 AM The cone will be very stiff as you press your fingers down on the cone it will have scratchy sound as you press it inwards.
saprano 09-30-08, 07:22 AM What? come on guys this AVS right? i need more answers.......please!:)
Raymond Leggs 09-30-08, 11:12 AM The voice coil will be melted into the VC former.
saprano 09-30-08, 11:25 AM i still dont understand, you want me push the woofer inward? i did that already but i didn't hear anything.
When you pushed in the driver, did it move freely?
Do you have a sound meter? Did you take measurements?
rlj5242 09-30-08, 04:31 PM i still dont understand, you want me push the woofer inward? i did that already but i didn't hear anything. Then you didn't deform the voice coil former when it hit the back plate of the magnet. There's a good chance there is nothing wrong and the lower bass output is all in your head. As mentioned, you need to measure it so that it can be confirmed.
-Robert
saprano 09-30-08, 11:53 PM When you pushed in the driver, did it move freely?
Do you have a sound meter? Did you take measurements?
Yes i pushed the driver and i heard nothing. it did move in and out freely.
saprano 10-01-08, 12:18 AM Then you didn't deform the voice coil former when it hit the back plate of the magnet. There's a good chance there is nothing wrong and the lower bass output is all in your head. As mentioned, you need to measure it so that it can be confirmed.
-Robert
I noticed a difference though, what could it be? did i get use to the sound?:confused:what to look for when i get the spl meter?
saprano 10-01-08, 11:36 AM Bump.
rlj5242 10-01-08, 02:16 PM I noticed a difference though, what could it be? It could be that you tore part of the suspension and there is degraded output of your sub or it could all be in your head. They same way that more expensive cables make systems sound better. You heard a noise and now something must be broken somewhere.
did i get use to the sound? Or you could have damaged your hearing.
what to look for when i get the spl meter? If you don't have a baseline set already from when you originally calibrated then you just need to perform a standard calibration using an SPL meter and a calibration DVD like Avia or VE. If you want to take it a step further, then you can graph your sub's in-room response with the meter and a set of test tones. You put the readings into your favorite spreadsheet along with the correction factors for your meter. Graph the results.
-Robert
JBLsound4645 10-01-08, 06:57 PM The voice coil will be melted into the VC former.
Yeah like arch welding.
What? come on guys this AVS right? i need more answers.......please!:)
You’ve got enough good answers on this thread to block up the Merseyside tunnel.
http://www.industrialpowerhouse.co.uk/img/news_images/Queensway%20Tunnel.jpg
I’d seriously change your signature because I know your taking the piss with all of us and I don’t funny anyone.
saprano 10-01-08, 08:34 PM Change it for what? i cant ask questions?anyway im bringing it to best buy to have them check it out. thanks for all the help guys!:rolleyes:
rlj5242 10-02-08, 05:51 AM anyway im bringing it to best buy to have them check it out. Good luck with that. You already know more than your average BB home theater salesperson.
-Robert
evilbeaver 10-02-08, 07:53 AM Play some test tones and make sure your mains are crossed-over above whatever tones you use.
saprano 10-02-08, 06:26 PM Good luck with that. You already know more than your average BB home theater salesperson.
-Robert
I ment for warranty, magnolia is suppose to service or replace anything under difinitives warranty. i might just get a sub from them.
saprano 10-06-08, 10:43 PM So i took took the sub to bestbuy and i think the magnolia guy has no idea what he's talking about. i told him my problem and all he did was plug it in, heard it rumble and told me theres nothing wrong:confused: i tried telling him its probably the amp or something is damaged inside, he said it ether works or it doesn't. he said if they send it out to the service center all there going to do is plug it in like he did, and hear that it rumbles and send it back.....what?:confused:so anyway i took it to another bestbuy, and brought it to the geek squad. this guy understood my problem better, so its been sent out for 2 weeks......do you think there going to really fix it? or do what that guy says and just plug it in? do they even know about this stuff as to actually open it up and check inside instead of just hearing that it rumbles?.
rlj5242 10-07-08, 09:59 AM That post just proved my point. As you can see, you will get different responses based on who you run into. So there is a chance your sub will land in the hands of a slacker who will plug it in and listen. Someone else may take it apart and test the impedance of the driver with a DMM (something you could have done) and run other extensive tests. It's a crap shoot. That's why we try to educate you on these things so that you can fix your own problems rather than relying on others. If you want something done right, you have to do it yourself. Or pay someone who will.
-Robert
saprano 10-07-08, 01:14 PM Yea you were right:o not that i doubted what you said about BB workers, trust me i know they dont know anything. but i wanted to see if hopefully they knew what the hell i was talking about, turns out i did know more about the sub than they did, you were right again:o speaking of paying to fix it, if my sub does come back un fixed( witch i think it will) do you know any audio dealer, or any place where i can take it to get the job done? i live in bronx new york. ( i should of done that in the first place)
saprano 10-24-08, 01:20 AM I just got my sub back from repair and they said theres nothing wrong with it:confused::confused: i have a 5 year warranty so it got sent out by geek sqaud.
Playdirty714 10-25-08, 12:52 AM My old Kenwood vr-707 receiver had a bug up its alley once in a while and I would have to reset it by unplugging the power cord and holding the power button on the receiver and plugging the power cord back into the power outlet. What happens is somehow the receiver sends out weak signals and I would have to reset the receiver. Try resetting the receiver.
saprano 10-25-08, 10:35 AM I'll try that thanks, is resetting it the same way on all receivers? i have a onkyo 705.
|