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Author Topic: Speaker problem  (Read 2589 times)

PeterJerauld

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Speaker problem
« on: September 04, 2013, 12:59:37 pm »

Last weekend, I lost the output on the LF driver in one of my speakers (Peavey SP2X). I was assuming that if the horn was working, the problem would be with the internal passive crossover, since what would damage a fifteen inch speaker that wouldn't take out a HF driver. So I have two questions. One, is that at all a logical assumption, and two, other than pushing on the LF cone listening for rubbing and checking the appearance of the crossover, is there anything else I should try to troubleshoot this?
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Tim McCulloch

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Re: Speaker problem
« Reply #1 on: September 04, 2013, 01:18:26 pm »

Last weekend, I lost the output on the LF driver in one of my speakers (Peavey SP2X). I was assuming that if the horn was working, the problem would be with the internal passive crossover, since what would damage a fifteen inch speaker that wouldn't take out a HF driver. So I have two questions. One, is that at all a logical assumption, and two, other than pushing on the LF cone listening for rubbing and checking the appearance of the crossover, is there anything else I should try to troubleshoot this?

Meter the woofer voice coil.  It should have a DC resistance of around 5-6 ohms.

Transducers die for 2 reasons:  long term heat build up, and mechanical damage due to over-excursion.
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"Practicing an art, no matter how well or badly, is a way to make your soul grow, for heaven's sake. Sing in the shower. Dance to the radio. Tell stories. Write a poem to a friend, even a lousy poem. Do it as well as you possible can. You will get an enormous reward. You will have created something."  - Kurt Vonnegut

Robert Weston

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Re: Speaker problem
« Reply #2 on: September 04, 2013, 01:19:43 pm »

Last weekend, I lost the output on the LF driver in one of my speakers (Peavey SP2X). I was assuming that if the horn was working, the problem would be with the internal passive crossover, since what would damage a fifteen inch speaker that wouldn't take out a HF driver. So I have two questions. One, is that at all a logical assumption, and two, other than pushing on the LF cone listening for rubbing and checking the appearance of the crossover, is there anything else I should try to troubleshoot this?

You can easly destroy a woofer before damaging a horn.  It's common to overheat a woofer by running too much "program" power to it (usually compressed and over a period of time).

Open up the speaker cabinet and remove the wires that connect the xover to the speaker - test each speaker individually; if they work, the problem is narrowed to the xover. 

Play some music thru the woofer.  If it "buzzez", it's probably overheated.  Remove the woofer basket and inspect the copper windings.  If they are black, the woofer is dead.
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Darin Ulmer

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Re: Speaker problem
« Reply #3 on: September 04, 2013, 01:22:42 pm »

Last weekend, I lost the output on the LF driver in one of my speakers (Peavey SP2X). I was assuming that if the horn was working, the problem would be with the internal passive crossover, since what would damage a fifteen inch speaker that wouldn't take out a HF driver. So I have two questions. One, is that at all a logical assumption, and two, other than pushing on the LF cone listening for rubbing and checking the appearance of the crossover, is there anything else I should try to troubleshoot this?

A.  Yes, you can lose a woofer without losing the HF.  Most common culprit in my experience has been people attempting to make a single 15 sound like a stack of subs.

B.  Take out the woofer and check for continuity across the speaker with a volt meter while disconnected from the crossover.  If there is no continuity then the voice coil or leads are done and you need a recone kit. 
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Tim McCulloch

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Re: Speaker problem
« Reply #4 on: September 04, 2013, 01:34:01 pm »

You can easly destroy a woofer before damaging a horn.  It's common to overheat a woofer by running too much "program" power to it (usually compressed and over a period of time).

Open up the speaker cabinet and remove the wires that connect the xover to the speaker - test each speaker individually; if they work, the problem is narrowed to the xover. 

Play some music thru the woofer.  If it "buzzez", it's probably overheated.  Remove the woofer basket and inspect the copper windings.  If they are black, the woofer is dead.

If the woofer is buzzing, it's not really usable regardless of any VC coloration.

For Peter:  if you find discolored voice coils, you can bet (and win) that the speaker was fed too much for too long.  This can develop to the point that the coil comes unwound in the gap or even result in electrical fire that then sets the cone alight.

If the coil is open or shorted, you can probably bet on too much heat as well.

If the cone is separated from the voice coil form, is torn around the outer suspension, or the spider (the wavy round suspension that centers the coil form in the gap) is loose from the frame, you have mechanical damage from over excursion (too low freqs, too loudly; either or typically both).

Tthe good news is that the Black Widow replacement basket is relatively inexpensive ($90 online) and can be user-serviced.
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"Practicing an art, no matter how well or badly, is a way to make your soul grow, for heaven's sake. Sing in the shower. Dance to the radio. Tell stories. Write a poem to a friend, even a lousy poem. Do it as well as you possible can. You will get an enormous reward. You will have created something."  - Kurt Vonnegut

Douglas R. Allen

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Re: Speaker problem
« Reply #5 on: September 04, 2013, 03:50:37 pm »

Last weekend, I lost the output on the LF driver in one of my speakers (Peavey SP2X). I was assuming that if the horn was working, the problem would be with the internal passive crossover, since what would damage a fifteen inch speaker that wouldn't take out a HF driver. So I have two questions. One, is that at all a logical assumption, and two, other than pushing on the LF cone listening for rubbing and checking the appearance of the crossover, is there anything else I should try to troubleshoot this?

Peter;

I have a pair of Sp2X as well. Its sounds like but I have to ask are you using the 1/4 inch full range inputs? Has anyone at anytime plugged into the Speakon inputs?
The Speakon inputs are switching jacks. When you go into them they disconnect the input from the built in crossover. I keep mine clean but I have seen where this jack has "stuck open" and not fed either the horn or woofer because of it.

If you check your speakers as others have mentioned and they seem fine and yet don't work try running a speakon jack in/out (with cd/ipod type music playing at a low level) and see if maybe the issue is there.

Douglas R. Allen
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PeterJerauld

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Re: Speaker problem
« Reply #6 on: September 10, 2013, 12:47:54 pm »

My apologies for not thanking you all for your responses before now. When I pulled the speaker out and removed the magnet, the somewhat obliterated voice coil made it pretty obvious what the problem was. Gotta love replaceable baskets!
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ProSoundWeb Community

Re: Speaker problem
« Reply #6 on: September 10, 2013, 12:47:54 pm »


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