subs stop playing

[atlninja82 10+ year member]

hey guys i have 2 rockford fosgate p3 slims. one day i was bumpin and they just like quit playing. but then after made like a scratchy noise. so i shut off the headunit and let them rest for about 10 minutes and then they played normally again and were fine for the rest of the ride home. and then today they did the same thing. are they blown? if not what is this?

thanks,

-eric

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[bladebarrier 10+ year member]

hey guys i have 2 rockford fosgate p3 slims. one day i was bumpin and they just like quit playing. but then after made like a scratchy noise. so i shut off the headunit and let them rest for about 10 minutes and then they played normally again and were fine for the rest of the ride home. and then today they did the same thing. are they blown? if not what is this?
thanks,

-eric

Can you describe the "scratchy noise" a little more. Does it only happen after running the subs pretty hot for an extended time?

It sounds like you might have the start of a voice coil failure due to heat related damage. This could be from overpowering the speakers ability to dissipate heat in the voice coil due to an amplifier clipping heavily. You essentially end up pushing what would normally be "peak" power levels into it for bursts that are longer than intended, as the sin waves become flattened at the top and bottom (ok, not sin waves as you weren't listening to test tones, but this can happen during music as well).

Could the amp have been clipping for a while before it first had an issue? It can be more difficult to notice this type of distortion in bass frequencies due to the ear's inability to perceive the frequency range accurately.

If you CAREFULLY push directly in on the woofer, by placing your hand carefully on the cone in a way as to not bend or damage any spot, do you hear a scraping sound? If you don't feel comfortable doing this test, take it to a pro and have them look at it instead.

 

[atlninja82 10+ year member]

i really cant describe it. its weird. but it just does it really quick and stops. but yea that sounds like what it might be. the only thing i can think of why it just started doing it is because before i had no electrical upgrades and my voltage dropped really low and im guessing made the amp put out less power. and now i have 2 upgraded batteries and the big 3 and now i get hardly any voltage drop so im guessing the subs just started seeing more power. thats my guess. and the first time it had happened it was after playing it for about 30 minutes. so im guessing that could be it. and thats the first thing i did when this happened is push on the sub and it felt normal.so are these subs about done?

 

[bladebarrier 10+ year member]

i really cant describe it. its weird. but it just does it really quick and stops. but yea that sounds like what it might be. the only thing i can think of why it just started doing it is because before i had no electrical upgrades and my voltage dropped really low and im guessing made the amp put out less power. and now i have 2 upgraded batteries and the big 3 and now i get hardly any voltage drop so im guessing the subs just started seeing more power. thats my guess. and the first time it had happened it was after playing it for about 30 minutes. so im guessing that could be it. and thats the first thing i did when this happened is push on the sub and it felt normal.so are these subs about done?

The fact that it doesn't produce a rubbing noise might mean that it's not the driver. I still am guessing that it is though.

Here are some more of my thoughts on what could be happening:

It's hard to tell without being there, of course, but they might run fine for a while. Just because heat damage is generally permanent, it doesn't mean the drivers will get worse, as long as your careful. The damage might not even be an issue for most conditions, but if you keep pushing them hard, they're probably going to fry.

I'm also not 100% sure it's a driver failure, even though it does sound like it to me. Was the noise so loud that you heard it over your highs, or was it just the stopping of all sound, and then the noise after that you heard? If they stopped producing any sound at all, they could have literally started shorting out. This can be a very bad thing as it could put your amplifier at risk.

Are both speakers running off of the same amplifier channel? If both speakers stopped at the same time, and are running off of separate channels, it could actually be the amp. Even if they're running off of the same channel, it's a possibility that the amp is failing. The reason I'm guessing that's not the issue is because most modern car amps have decent protection circuits, and would shut down on purpose rather than go into a partial shutdown mode and wreck havoc.

If they're under warranty, the manufacturer might be willing to take a look at them for free, or not. I would email their support team and ask them what they think maybe happening, and if they'd be willing to run a diagnostic on them for you. They may be able to see right away by just checking resistance levels across the terminals with an ohmmeter.

Keep in touch and let us know what you find out. It may help out others that run into a similar situation.

 

[atlninja82 10+ year member]

thanks a lot for the replies. i hope i can get this figured out soon. i think im gonna run to walmart and get a dmm and check my impedance across the voice coils. they a d2's so if they show 2 ohms on both sides that should mean the voice coils are fine right? and yea they both shut off and made that noise and my amp was still on. and yes the subs are running off the same channel. should i take them out and check for any any physical damage i could see maybe?

 

[bladebarrier 10+ year member]

thanks a lot for the replies. i hope i can get this figured out soon. i think im gonna run to walmart and get a dmm and check my impedance across the voice coils. they a d2's so if they show 2 ohms on both sides that should mean the voice coils are fine right? and yea they both shut off and made that noise and my amp was still on. and yes the subs are running off the same channel. should i take them out and check for any any physical damage i could see maybe?

You probably wouldn't see the damage. The area where the voice coil would generally have been damaged is inside the magnet area. You would destroy the sub by trying to get to it.

I'm not 100% on how they test the resistance levels for signs of damage. I'd call up Kicker directly, and see if they can walk you through how to check it yourself.

 

[x2o 10+ year member]

thanks a lot for the replies. i hope i can get this figured out soon. i think im gonna run to walmart and get a dmm and check my impedance across the voice coils. they a d2's so if they show 2 ohms on both sides that should mean the voice coils are fine right? and yea they both shut off and made that noise and my amp was still on. and yes the subs are running off the same channel. should i take them out and check for any any physical damage i could see maybe?

Yep, check the voice coils. If it is blown you will either get a reading of nothing meaning the coil unwound, or really low/high, meaning the coil burnt. If it is between 1 and 3 then odds are the VC's are still fine and it may be something else.

 

[boomzilla 10+ year member]

thanks a lot for the replies. i hope i can get this figured out soon. i think im gonna run to walmart and get a dmm and check my impedance across the voice coils. they a d2's so if they show 2 ohms on both sides that should mean the voice coils are fine right? and yea they both shut off and made that noise and my amp was still on. and yes the subs are running off the same channel. should i take them out and check for any any physical damage i could see maybe?

Yeah just test the coils with a dmm, if they dont read 1.6-2.2 ohms, it's fuxxored.

But if it reads within that range, they're fine. I think you may have just been beating on them for a little too long, maybe they started bottoming out, is your box ported or sealed?

 

[x2o 10+ year member]

Also, check any and all wiring. This sounds like a faulty wire or a crappy ground. Not sure if bladebarrier already recommend this, his posts are too long for me to read in their entirety //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif.

Also, is it doing it constantly now? If it is, check out the amp when it happens, does it kick into protect, does it turn off, etc.

IMO, check your wiring ASAP. a loose speaker wire could be moving when certain bass hits and causing the amp to see a really low ohm load from the subs which would make it protect. Also, a bad ground can wreak havoc in many different ways, so check wiring in my opinion.

Also check the voice coils as you said you were going to.

 

[GAM3OVR 5,000+ posts]

Can you describe the "scratchy noise" a little more. Does it only happen after running the subs pretty hot for an extended time?
It sounds like you might have the start of a voice coil failure due to heat related damage. This could be from overpowering the speakers ability to dissipate heat in the voice coil due to an amplifier clipping heavily. You essentially end up pushing what would normally be "peak" power levels into it for bursts that are longer than intended, as the sin waves become flattened at the top and bottom (ok, not sin waves as you weren't listening to test tones, but this can happen during music as well).

Could the amp have been clipping for a while before it first had an issue? It can be more difficult to notice this type of distortion in bass frequencies due to the ear's inability to perceive the frequency range accurately.

If you CAREFULLY push directly in on the woofer, by placing your hand carefully on the cone in a way as to not bend or damage any spot, do you hear a scraping sound? If you don't feel comfortable doing this test, take it to a pro and have them look at it instead.

first of all it's sine waves not sin waves.

Second music is dynamic. Sine waves aren't.

A clipped signal is not a sine wave. A clipped signal is a form of waveform distortion that occurs when an amplifier is overdriven. It's when you try to push more volts out of the amp then it can do. A sine wave, when played and done right, pushes the amp just a hair below clipping, if you have clipping, get a bigger amp or turn yo ish down!

 

[bladebarrier 10+ year member]

first of all it's sine waves not sin waves.
Second music is dynamic. Sine waves aren't.

A clipped signal is not a sine wave. A clipped signal is a form of waveform distortion that occurs when an amplifier is overdriven. It's when you try to push more volts out of the amp then it can do. A sine wave, when played and done right, pushes the amp just a hair below clipping, if you have clipping, get a bigger amp or turn yo ish down!

True, the correct term is "sine". I apologize if anyone was thrown off by that. I often think of it in terms of the mathematical abbreviations of sin, and cos, and didn't expect the need to clarify the difference.

And yes, no one listens to pure sine waves unless they're metering to adjust eq's, etc.

 

[bladebarrier 10+ year member]

Also, check any and all wiring. This sounds like a faulty wire or a crappy ground. Not sure if bladebarrier already recommend this, his posts are too long for me to read in their entirety //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif.

I also don't like to read. //content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif

Just kidding.

I'll try to keep more to one thought at a time. No one else had responded to him, so I threw out as many ideas as I could, with the hopes that one of them would sort it out.

 

[atlninja82 10+ year member]

ok well thanks to everyone for helping me out with this. i think i have a good idea of what to check and i should soon find the problem. ill let you guys know what i find tomorrow!

thanks again,

-eric

 

[bladebarrier 10+ year member]

ok well thanks to everyone for helping me out with this. i think i have a good idea of what to check and i should soon find the problem. ill let you guys know what i find tomorrow!
thanks again,

-eric

Good luck, Eric.

Let us know what you find out. I'm starting to shift to the idea, like those above, that it could be an electrical issue, so check every wire you can with your new meter, and if you can, swap the amp out with a friend's, to see if it fixes the issue.

 

[atlninja82 10+ year member]

ok well i went out today and started bumpin again. and it shut off. i get to mcdonalds and my friends wanna hear my system. so im bumpin for like 6 songs straight. nothing has turned off. but then i start driving and sure enough it turns off again after like a minute. it was dark and my amp has blue leds on it so i can see under my seat when its on and off. and when the music turned of the lights of the amp were flickering. so thats good news to me. its the amp and not the subs. so does anyone have any suggestions on what this could be. it has to be wiring of some sort. this is the only thing i can think of. my second battery (kinetic hc 2400) has 3 1/0 wires coming off of the - terminal. but the threads are stripped in the battery so i cant get them off.so i ran one of the wires to a distro block and had 2 4 awg wires runng out of it. one went to the amp and one went to the chasis. this is the only thing i can think of.

thanks,

-eric