Do speaker drivers degenerate with age?

[Greg.]

This is a bit of a subjective question but I'm interested in the thoughts of all here on this topic.

Common sense would suggest that as a speaker driver gets used and becomes older, it's effeciency and performance will degenerate. If that is the case, how does one identify this? It reminds me of identifying a O/P valve becoming old and unservicable. Because the degradation in performance is gradual, many of us in our domestic listening rooms only identify the issue when we try a replacement set of valves or the old ones start to hum or develop some pyrotechnics.

IMHO, that needs to be measured alongside quality vintage drivers (such as Goodmans etc) that continue to perform well and when physical integrity is compromised such as the need for a replacement outer cone suspension support ring, a service sorts them out. But does it? Do they then continue to perform optimally or with tiredness, despite the new parts?

In particular, what about tweeters? How do you know when they are getting worn out without any obviously visual physical degradation. Again, IMHO, sound degradation may occur with the passage of time, but is the only way to identify it, owing to regular and familiar listening, when the tweeter breaks or (unlikely) you fit a replacement unit?

I'm really interested to hear what others think on this topic. I am particularly mindful that we have very satisfied members who still use drive units that are over 50 years old. I recognise it is all very subjective, but it would be good to build an understanding of the experience and views of others. Thanks.

[John7]

Hi Greg.

My 1975 vintage Monitor Audio MA1 speakers have had 2 lots of tweeter replacements as either left or right failed and both midrange speakers replaced as MA upgraded them in about 1978 (?).

The only drive units not replaced are the KEF B139 bass units which are still going strong!

I take your point about gradual degeneration, but I still get more than enough bass and the replacements for the other units have always sounded slightly different though whether they were better is impossible to say.

Regards,
John

[Baggy Trousers]

In my estimation, the answer is "Probably, no".

Disregarding things like biodegradeable suspension foam and so on, there isn't much in a conventionally designed and properly manufactured speaker that is likely to change over the years. No doubt laboratory testing of magnet strength, spider compliance or oxygen contamination of the copper voice coils (!) might reveal some departure from the original performance but since the bits (in my case) are well over forty years old, replacement parts with which to make a direct comparison will be of a similar age, so we should learn nothing. And in any event, I would not trust the opinion of anyone who claimed to be able to hear a difference.

Of course, my views are restricted to quality products like Hartley, Baker, Tannoy et al; perhaps there is significant degeneration with inferior products but that is good - it encourages us to go out and buy something better when they fail.

But what do I know?

Baggo.

[Ali Tait]

Greg, I think the field coil drivers in Will's OB's are about 70 years old. They certainly sounded good!

[Ianm2]

magnets lose magnetism over time, I recall alnico are particularly susceptible to losing gauss

as you have correctly identified, suspensions will sag with gravity, they will probably lose elasticity with use and time, cones will sag, perhaps if not treated they will absorb moisture, go soft/hard with time, glues change, decompose, all sorts of things.

tweeters are the same as woofers, they are simply inverted, I would say 5-7 years till they need replacing, you can't tell as your ears adapt again as you have said.

they MAY be more susceptible as they vibrate much faster, albeit at minute excursions. visualize a motorbike engine going fast as opposed to a big ship engine going very slow.

older ones may last better as they were usually built better, but still the suspension and cones will degrade, esp. if paper.

just look at old books to see how paper changes with age, gets dusty, thinner, smells, changes colour.

a recone will work wonders or alt. destroy any old character, remember too xovers go out as capacitance changes and shifts the xover frequency, again only identifiable when you replace them.

its down to common sense.

ALL mechanical things have a lifetime, no matter what anyone says, modern ones 7 years, older perhaps more. visualize your car in this respect.

the only ppl who really know in all respects, are the manufacturers, all us amateurs can do is offer a misinformed opinion, the only ones who know the lifetime of such parts are those who test them to destruction in all conditions, if indeed this is done. only the makers can truly tell the answer to this.


why bother if it still sounds good to you? sometimes we get too anal

[Greg.]

Originally Posted by Ianm2

why bother if it still sounds good to you? sometimes we get too anal

Well yes, that's true. I was just sounding out what others might think. Thank you for your other observations. At the time of posting, I thought my tweeters were not as accute as I originally experenced. On refection, they remain probably as good as new but no matter, I have a pair of new unused to replace them with if I feel so inclined.