Car amp with pro woofer?

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Bought a pro woofer and the only thing I have to test it with is a car amp at the moment. This is a junky but known working car amp. I hooked it up and it sounds good at mid volumes but higher up with the smacks from drums I get crackling from the woofer.

Is the woofer blown or are they just not supposed to be used with car amps?

By the way the woofer is 300watts and the car amp is 200 watts and the amp is rated for the impedance of the woofer, and the sound crackles at like 1/3 power.

Any help is appreciated.
 
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sounds like a loose voice coil
ebay is gaining momentum ever since more municipal dumps are charging dump fees

Hello everyone.

This is a Behringer Eurolive 15W300A8, 15" 300watt continuous, 8ohm actual pa woofer. They are used in many of the powered woofers behringer sells. Its not the best pa woofer but it certinaly should work. I bought it off of eBay and it was sold as an unused spare, yet they said it worked and sounded perfectly and when I got it I see paint missing around the screw holes (all of which implies they did in fact use this woofer).

The car amp is connected in a home to a good quality comptuer power supply and has been running like that for 4 months or so. At 12Volts it will draw over 10amps (I have an ammeter on it) so it at least draws 150 or so watts but even at maybe 40 or so the woofer starts to crackle. Bear in mind though that its rated for 200watts at 4ohms (which is how I've been running it for 4 months) so its not actually giving the woofer that much power if its at 8 ohms and drawing only 50watts or so.

It does this both in and out of an enclosure. If I manually move the woofer myself I don't hear scratching, moving the tinsel leads also seems to have no effect on the crackling noise.
 
Agree and add: download a low frequency sweep .mp3 , something like 20Hz to 200 or 400Hz, which is often used to test car subwoofers and test your speaker.
Or get some frequency generator software and do the same.
I bet the woofer will work relatively well but at some frequency it will make horrible buzz, just when the loose part resonates.
When it does, move/flex/push cone different ways with your fingers trying to find it.
Doesn't mean you'll *repair* it, unless it's something very simple such as loose dustcap rattle or tinsel wires hitting the cone or some part of the frame, but you might get lucky.
 
Could have a charcoaled VC, when it overheats it starts to bubble up & expands the coating...taking up space, zeros out the VC clearance....so it scrapes along. ???? In my case it's one of those 6X9s with the pole piece with a hokey foam dust-seals...lots of pure dirt, dust gets in these, almost like I have to pick out pieces of dirt.

______________________________________________Rick.........
 
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Could have a charcoaled VC, when it overheats it starts to bubble up & expands the coating...taking up space, zeros out the VC clearance....so it scrapes along. ????

______________________________________________Rick.........

Well it checks out fine with an ohm meter and I'm not pushing more than 50 watts into it so I don't see how it can be overheating like that, besides the fact that it is indeed cold to the touch and after playing horribly I can turn it off and move it manually just fine.
 
Your computer power supply wasn't designed to supply an audio amp and may be going into overcurrent or overvoltage protect mode on audio peaks. It is only giving your amp 12 to 12.5 volts when it wants 14 volts too. If you have a scope, or even a voltmeter observe the power supply output to see if anything changes when the crackling starts. If all else fails, borrow the battery from your car and repeat the test. I have heard crackling caused by wimpy switchmode power supplies on audio amps...especially class D amps. A big fat cap across the power supply output might help, or it might cause the power supply not to start up, depends on the power supply.
 
Your computer power supply wasn't designed to supply an audio amp and may be going into overcurrent or overvoltage protect mode on audio peaks. It is only giving your amp 12 to 12.5 volts when it wants 14 volts too. If you have a scope, or even a voltmeter observe the power supply output to see if anything changes when the crackling starts. If all else fails, borrow the battery from your car and repeat the test. I have heard crackling caused by wimpy switchmode power supplies on audio amps...especially class D amps. A big fat cap across the power supply output might help, or it might cause the power supply not to start up, depends on the power supply.

I know my brands of pc power supplies well, and this is definitely a reliable power supply and it is rated at 1000watts, most of which is on the 12V rail.

I can almost guarantee you that the amp and psu are not the issue considering I've pulled much more wattage from both that psu and amp using a 12in car sub for 4 months, and I don't see why a quarter of the wattage from both would cause it to crackle all of the sudden.

However I may throw my scope on that 12v rail just to see what's going on because I do always notice that stuff dims (lights in the room and on the amp) the tiniest bit (not visible unless you look at them the right way) when using this amp and psu so I do know it draws a lot in pulses. This is the only thing that would hint that the amp and psu are making the crackling problem, coupled with the fact that it looks like everything dims just as much with the 12in speaker maxed out, as this possibly broken 15in at about 1/4 volume.

As far as caps go the best I can do is maybe 20,000 on the 12v rail which I'm not sure is big enough to make a difference.

Thank you very much for helping me out, I'll try some things and let you all know whats going on tomorrow.
 
Well I'm very pleased to announce that the woofer is actually fine, couldn't sound better!

I hooked it up to a Kenwood KM-993 reciever which puts out 150WPC into 8ohm and WOW this woofer is nice.

The kenwood only supplied half of the woofers rated power and with just that one woofer hooked up, it was louder and more full than any of my other equipment combined. I LOVE PA equipment, and will definitely add to my collection now!

I couldn't believe how full the mids of songs sounded, because with my other equipment the highs and lows were fine, but mids were lacing, but with this 15" hooked up alone, it handled everything fine.

I think it'll be even better when I get a crossover on it and set it to handle mids and lows and get some horns or something to do the highs!

Thanks for all of you help guys, you did finally persuade me to try something other than that car amp!
 
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