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Old 29th October 2003, 10:38 AM   #1
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Default Do loudspeakers wear out?

Can the surround and spider eventually go soft or something? In particular, do modern butyl rubber ones have some kind of wearout mechanism? Does the magnet eventually get partially demagnetised from the voice coil applying an AC field to it?

Basically, is it ok to let the rest of the household have my nice new speakers blaring all day long, or are they being "used up" somehow?
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Old 29th October 2003, 10:50 AM   #2
Cobra2 is offline Cobra2  Norway
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Default Interesting Q...

In my opinion, they don't wear out, but then again, there are other factors that can reduce their life.

The obvious fysical abuse, from touch, air pollution, sun, cats...
The use-abuse, playing too loud, (bottoming out), overheating, ...

I have had a pair of Tannoys 638, and more than 10years after, they still sound as good as, or maybe better than new.
The same goes for a pair of AudioVector speakers...

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Old 29th October 2003, 10:59 AM   #3
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What wears out, if you will, in my experience, is often things like the glue to attach the cone to the frame, and the glue to put together the voice coil assembly. That is however more time related than use related. Humidity and/or direct sunlight would accelarate that. But still, we're probably talking 20+ years or so.

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Old 29th October 2003, 11:51 AM   #4
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I have seen plenty of pro sound speakers (JBL, EV etc) that have become very saggy in their suspension (mainly spider) from long term use - although most of this useage would be near, at, or exceeding maximum ratings. Normally characterised by a cone that seems to flop in and out without defined resting place when cone moved by hand.

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Old 29th October 2003, 12:03 PM   #5
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So we are lucky that we have someone from a place of intense speaker abuse, to get first hand info about the subject !

But that's right: pro sound equipment is often subject to heavy abuse (not only with country music ) and subsequently increased wear and tear.

But also your home speakers are subject to ageing. Suspensions will loose their stiffness, depending on materials used.
Surrounds made of foam may rot.
Drivers that are radiating vertically (e.g. floor radiating subs and speakers stored in cartons for years) are subject to cone sag.

I have a pair of small boxes using Dynaudio 17W75 drivers.
I once connected them to a P.A. amp. Even when driven hard they didn't bottom due to their progressive restoring force (the sound got blurred of course). I doubt that one could do this for extended periods of time without weakening the spider.

Regards

Charles
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Old 29th October 2003, 01:07 PM   #6
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All physical things degrade and speakers are not exempt. The foam on my Tannoys certainly isn't
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Old 29th October 2003, 01:26 PM   #7
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Of course Speakers wear out after prolonged heavy use

The "Pig Tail" connecting wires to the voice coil is a weak point on many Low Cost Speakers

On the other hand, new speakers need "Running In" by loosening up and will sound better after some use

Abuse by driving them too hard will eventually destroy them

As an aside, how are loudspeaker "Power Ratings" determined

Is it how loud and for how long you can operate them before they fall apart or burn out?
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Old 29th October 2003, 06:58 PM   #8
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I think speakers often wear out their welcome.
Actually, well made speakers seem to have an extraordinarily long life. There are a large number of ARs and KLHs and so on from the 60s that are still going strong, and there are plenty of earlier speakers still in use from the earliest days of hifi -- Bozaks, JBLs and Altecs and so on. Obviously foam degenerates, and capacitors can fail, and glues fail, but a lot seems to depend on the environment the speakers were in. Modern speakers are often less confidence inspiring in their construction.
Oh -- it seems like electrostatics really do wear out in a way that dynamic speakers don't. Pinholes from sparks, loss of tension and so on...
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Old 29th October 2003, 08:28 PM   #9
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OK......Here's what I have noticed wearing out in all of the loudspeakers I have repaired:

1) This is the most obvious one. Foam surrounds will rot out whether they are heavily used or just sitting in your grandmother's attic. the materials used to make the foam surrounds just break down over time. There's nothing we can do about it. Oh well, time for a recone.

2) Cone fatigue. This usually only occurs in professional loudspeakers that are being driven very heavily night after night in club PA systems where the DJ thinks that the red clip lights actually make it sound better. I can't complain though, it's job security for me. Cone fatigue also shows up in speakers that have spent their life in the family room with a bay window. The UV light from sunlight will degrade the paper in the cone, reducing the cone stiffness. When this happens, cone breakup begins to happen at lower and lower frequencies. Also, the user will start turning up the speakers louder and louder to get the sound they are used to. If the cone is degraded too much, it will actually tear right through about a third of the way up the cone. I don't see this often, but it does happen.

3) In loudspeakers that see a lot of heavy use, the voice coil can actually start to wear out. The color of the insulation on the VC wire begins to darken, and the insulator can melt, causing a short in the VC.

4) I have seen the paper surrounds in very early JBL D series speakers crack. The cracking actually occurs perpendiculer to the surround. Or, from the inside to the outside. Usually, a little bit of black dome glue can seal these cracks but once the damage is done, the speaker will always be damaged.

5) Every now and then, I will see the glue fail between the cone and the surround. Usually when this happens, it is caused by a defective installation and should be warrantied by the service center that did the original construction of the cone. I have never seen this on older speakers that have been in service for years.

6) A less obvious, but still important, thing that can happen is the loss of magnet efficiency. The AlNiCo magnets of the early years, and the newer Neodimium magnets can actually lose their power. AlNiCo V magnets naturally lose their magnetic fields over time wheather they are degraded by heat or not. This is one of the reasons that the '59 Gibson Les Paul sounds so good. They used the AlNiCo V magnets. Now, 40 years later, the magnets have lost some power, and the pickups are a little softer and snoother sounding. This, thankfully can be fixed. There are several places around the US, and I'm sure there are plenty in the rest of the world, that can re-magnatize your vintage speakers. Orange County Speakers comes to mind here. As far as the newer Neodimium magnets, just don't over-power these. Please!!!!! When these magnets get heat stressed by someone overpowering the speaker, they lose thier magnetic field. I can't think of anywhere that can remagnetize these speakers. I've asked Orange County if they can do it, and the answer was a big, firm NO.

7) The whole suspension system can wear out. This basically means that the restorative forces in the speaker lose their effectiveness as a spring. Any spring be it metal, paper, rubber, etc. will eventually lose it's elasticity over time. If it is only the surround that has worn out, this can usually be replaced. If the spider is worn out, it's usually a good idea to re-cone the whole speaker. As spiders usually take quite some time to wear out, chances are that the cone and surround are also worn out and should be replaced.


If you are worried about your speakers wearing out within a few years because your family is cranking the stereo, I wouldn't worry too much about it. As long as you are not clipping the inputs of your amplifier, and you are not bottoming out your voice coils, your speakers should last for decades. I would only worry if you get your giant 5000W home stereo amp built Circlotron.

Cheers,
Zach
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Old 29th October 2003, 08:37 PM   #10
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Quote:
Originally posted by Richard C
All physical things degrade and speakers are not exempt. The foam on my Tannoys certainly isn't

Richard, you should contact Tannoy directly and see if the can replace the foam for you. If they can't do it, they can recommend a shop that can. Never throw out a good pair of Tannoys.

Cheers,
Zach
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