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Blown Speaker Recovers

Community Veteran
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Registered: 23-09-2010

Blown Speaker Recovers

I said goodbye to my "100 year" old stereo as I got a nice compact Sony HiFi off freecycle. My old speakers are OK apart from the fact that one didn't work. I swapped them over and neither worked so I guessed that as well as the speaker not working the long lead under the floorboards to that speaker must be damaged as well.
I took the speaker out of its cabinet and tried it direct and it still didn't work. Tried testing with a multi meter, set to ohms as I read online, and there was no reading. The good one read about four. No reading is supposed to mean it's blown.
I was just about to bin it when I thought I might just as well go the whole hog and give it the 9 volt battery test as well. It actually clicked. It's not supposed to do that. Tried the multi meter again and it was now reading around four as same as the good one. Connected it back to the HiFi and wonder of wonders it's now working.
I was lucky with the under floor wire as as it was pulling through ok I knew it wasn't a complete break. Sure enough the mice had only chewed through halfway several feet in. A quick bit of soldering, pull the wire back through and it was done.
Don't really know much about speakers except what I had to read online. So I can only assume that because of the wire break this speaker wasn't used for a few years so maybe it was "stuck" in some way.
Maybe I'm a soft git but the ironing now seems less of a chore when done to the sounds of Roxy Music. Smiley
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Re: Blown Speaker Recovers

There is no "stuck" with speakers - the terminals go to a coil of wire and that is about it.
Either you had a dirty / corroded contact which caused the issue or a loose contact between the terminal and the coil.
It could also be that the speaker had blown with a  fractured voice coil but the 9v battery managed to weld the microfracture back again - the speaker may work for a while then die again or it might be fine for the rest of its life.
If you'd actually pulled the speaker from the cabinet that would rule out any crossover or protection devices in its path.
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Re: Blown Speaker Recovers

Hmm... Yes, the wires go to a coil.... the current passes through the coil,... and that creates movement in the "magnetic" part of the diaphragm.... I would suspect that the magnet part had, indeed, got stuck, probably with a small amount of rust, or possibly dust... and shoving 9volts up it`s. xxxx gave it the necessary to shift the magnet enough to displace the rust/dust  Wink
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Re: Blown Speaker Recovers

But that wouldn't explain why the resistance between the terminals measured open.
Community Veteran
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Re: Blown Speaker Recovers

I did check it several times, confirming any readings, so the chance of a simple bad connection is remote.
Either way it's working now something I did not expect.
And it's nice when you spend a bit of time on something that actually ends up saving you money.
Fingers crossed it keeps working.
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Re: Blown Speaker Recovers

I recently wired up my new A/V receiver.
I ran the unit's speaker setup and it reported a missing front right speaker.
I disconnected and reconnected the wire and re-checked without success.
I stuck a meter on the receiver end of the wire which showed ok.
Reconnected....failed.
Took it back off, found an iffy point on the wire, cut it back and tried again...failed.
Found some more cable and replaced the wire....success Smiley
There must have been another break in the wire further down.
What started out as a 30 minute job turned into 3 hours Roll eyes
When I pull a cable under the floor I also drag a length of strong string with it just in case another cable is needed later on.
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Re: Blown Speaker Recovers

Quote from: DomS
But that wouldn't explain why the resistance between the terminals measured open.


If your meter read. 0 (zero) then it was showing a short circuit... not open circuit....
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Re: Blown Speaker Recovers

Just regurgitated this thread to ask one more question.
Does it really matter getting the speaker wires the "right" way around. I've heard things like "they will be out of phase" and the like.
My pairs of wires are a single colour so I have no real way of knowing. I suppose I have a 50 50 chance of being right but on the numerous occasions over the years it couldn't have always been right.
But the speakers always seem to sound OK. So does it matter?
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Re: Blown Speaker Recovers

If the speakers are out of phase it messes up the stereo image and the bass....so yes it matters.
What I've done in the past is connect a 1.5 volt battery to one speaker and note which way the cone moves...marking one terminal.
Then do the same with the other speaker.
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Re: Blown Speaker Recovers

Any definite way of testing or is it only a matter of the ear and swapping a wire pair around to check?
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Re: Blown Speaker Recovers

I've edited my post...and that's assuming you can see a speaker cone.
Is there no tracer on the wire pair, sometimes like a moulding.
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Re: Blown Speaker Recovers

Quote from: billnotben
Just regurgitated this thread to ask one more question.
Does it really matter getting the speaker wires the "right" way around. I've heard things like "they will be out of phase" and the like.
My pairs of wires are a single colour so I have no real way of knowing.


If you can........ get another length of wire, long enough to reach from "amp" end to "spkr" end.... ( over carpet )... join one end of "new" wire to existing one of pair... then use Multi Meter on OHMS to check for "continuity"..... then when you have found the right wire... mark it with some black insulting tape at each end... do the same with the other "pair"... and you should then be able to + and -  them to your amp and spkrs.....
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Re: Blown Speaker Recovers

Thanks for the tips.
Old speaker wires plain as are the under floor wires.
The cone movement seems to be the way to go. I have an old bare speaker that I can use to test that and plenty of black tape.
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Re: Blown Speaker Recovers

That's done and my newer Sony speakers sound very nice.
My ancient Sanyo single cone 5w speakers have been retired.
Of course someone will say no wonder you couldn't tell with those old Sanyo's. Smiley
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Re: Blown Speaker Recovers

So.... did you just replace the speakers?  ( and hope for the best ! ! ! )    or did you do a "line test"  ( as suggested by me )... to sort out the  + and - leads?