Speaker break-in / burn-in

[mazersteven]

footballs

 

[Pogre]

Thinking about what in a driver could change over time...
I would think (but don't know) that the strength of the magnet decays over time as a matter of entropy - does anyone know?
Otherwise I see the surround as the element being subjected to the most wear because it is the item that is getting physically flexed. Obviously, we had the older foam ones that totally disintegrated over time.
The cone has plenty of vibrations/flexes traveling through it, but I do not believe the amplitude of these vibrations is ever enough to result in material fatigue.

Unfortunately, I don't know that much about speaker design. I don't know if the surround is designed to be stiff in order to assist in returning the cone to it's neutral position. I am inclined to think they are designed to provide minimal resistance while maintaining a seal around the perimeter of the cone and the magnetic field controls position. If the latter, then a 5% difference of a very small (spring) resistance is a very, very small change in resistance.
I am also not so knowledgeable of plastics as I would like (on the topic of long-term wear). When I was a kid, any plastic hinge (like on a plastic index card box) was not long for this world, but soon thereafter, the "living hinge" was being advertised as a self-healing system that would result in on-going repair of the molecular bonds that were broken from flexing. This has definitely changed the way I look at durability of plastics. However, I always assume that there is, at least, some accrued wear despite the healing, but I don't know.
Is there a "materials specialist" in the house?

Properly cared for a magnet keeps its magnetivity indefinitely, tho high heat, (Curie point of the material) cold and exposure to other magnetic fields can have effects. Ferrite magnets have higher heat tolerance than neodymium (250°c v 80°c).

 

[Verdinut]

Alnico, which is an aluminum, nickel and cobalt alloy, was the first material used as a permanent magnet in the 1920's. Loudspeaker manufacturers only started to use it in the 1940's, and this type of magnet which is now rather expensive to manufacture is still being used on some high-end speakers. As we know, it was eventually replaced by the ceramic/ferrite material iirc in the 1970's, and we now have the neodymium which has a higher coercivity/weight and is used on many drivers.

Because of its low coercivity, the Alnico magnet is more susceptible to lose its strength. As a matter of fact, a woofer with an Alnico magnet, even slightly overdriven for short periods of time, will lose some of its sensitivity over time and need remagnetization. Some speaker manufacturers, Great Plains Audio is one, have been doing remagnitization work on Altec and other brand woofers.

Here is a good link on magnets:

Magnets & Magnetism Frequently Asked Questions | Magnet FAQs

www.intemag.com

 

[mtrycrafts]

This was not an experiment. It was a simple demonstration that Fs can drop somewhat with use. I've seen that many times before. To be a convincing experiment, this simple demo would have to go further:

1. The video did not ask the question if this drop in Fs was permanent (that is true break-in) or did the Fs return to the non-broken in state afterwards (warm up). (lovinthehd mentioned this in post #2.)
2. It assumed the stiffness of the spyder was the reason why breaking in was needed. Where was the evidence to support that idea?
3. And finally, the video never provided any listening test results. Could anyone hear a difference when the Fs had dropped 5 Hz?

Yes to all.
I bet the driver had an spl response at that 5 Hz lower point before the test, when the driver was cold. It didn't just come out of nowhere.
Further, what was the spl difference at that point before and after and, is that below the JND at that frequency, not audible.

Does this change happen every time you turn the system on to listen? I bet it does, then it is a useless concern. Is one supposed to warm it up each time for X minutes?
Not in my house.

 

[mtrycrafts]

Properly cared for a magnet keeps its magnetivity indefinitely, tho high heat, (Curie point of the material) cold and exposure to other magnetic fields can have effects. Ferrite magnets have higher heat tolerance than neodymium (250°c v 80°c).

And? Where is the rest of the story? Must be more to it.
What happens with really high heat?

 

[Pogre]

And? Where is the rest of the story? Must be more to it.
What happens with really high heat?

Just off the top of my head man. I didn't do a deep dive!

 

[mtrycrafts]

Redirecting to Google Groups

Redirecting to Google Groups

And Tom Nousaine's work on this:

"Breaking Wind", Nousaine, Tom, Car Stereo Review, Jan/Feb 1997, pg 90-94. (Break in myth)

"Test Report: Dynaudio MW 190, 12" Subwoofer", Nousaine, Tom, Car Stereo Review, Oct 1997, pg 83-88. (More break in myth)

Just off the top of my head man. I didn't do a deep dive!

So, you just swim in the shallow end.
Me Too.

 

[Verdinut]

I think this is mostly perception without much proof, but I know of speaker manufacturers who state that break-in occurs over a number of hours (the number varies, by manufacturer) and in the case of Klipsch, they have a document that ends with "A small warning here: not all speakers will sound dramatically different after break-in. Some improve only marginally, while others do change in ways that may dazzle you. Either way, it’s possible that you’ll notice an improvement.".

What Klipsch is saying is marketing bullshit. After a break-in, no speaker will sound different as there are minimal Thiele/Small parameter changes, the Fs/Qts ratio doesn't change and no one will be able to tell the difference. As a matter of fact, not all woofers will get a lower Fs so there's no break-in in such instances. This happened to a Hi-Vi woofer which I did some test on several years ago.

 

[Verdinut]

This was not an experiment. It was a simple demonstration that Fs can drop somewhat with use. I've seen that many times before. To be a convincing experiment, this simple demo would have to go further:

1. The video did not ask the question if this drop in Fs was permanent (that is true break-in) or did the Fs return to the non-broken in state afterwards (warm up). (lovinthehd mentioned this in post #2.)
2. It assumed the stiffness of the spyder was the reason why breaking in was needed. Where was the evidence to support that idea?
3. And finally, the video never provided any listening test results. Could anyone hear a difference when the Fs had dropped 5 Hz?

1. If the Fs dropped with the break-in, it is permanent. There is no such thing as a temporary break-in in loudspeakers.
2. It's most likely the spider suspension that loosened with the break-in, and obviously the case if the Fs dropped and the surround is foam or rubber.
3. With any drop in Fs, the minimal change in Fs/Qts ratio results to trivial changes in performance. Why people find differences after a break-in period, it's because of anticipation or they believe hearsay or manufacturer's bullshit.

 

[ATLAudio]

1. If the Fs dropped with the break-in, it is permanent. There is no such thing as a temporary break-in in loudspeakers.
2. It's most likely the spider suspension that loosened with the break-in, and obviously the case if the Fs dropped and the surround is foam or rubber.
3. With any drop in Fs, the minimal change in Fs/Qts ratio results to trivial changes in performance. Why people find differences after a break-in period, it's because of anticipation or they believe hearsay or manufacturer's bullshit.

So would you conclude that this video is over exaggerating the effect of “break in?” If so, why?


Sent from my iPhone using Tapatalk

 

[lovinthehd]

1. If the Fs dropped with the break-in, it is permanent. There is no such thing as a temporary break-in in loudspeakers.
2. It's most likely the spider suspension that loosened with the break-in, and obviously the case if the Fs dropped and the surround is foam or rubber.
3. With any drop in Fs, the minimal change in Fs/Qts ratio results to trivial changes in performance. Why people find differences after a break-in period, it's because of anticipation or they believe hearsay or manufacturer's bullshit.

Seems to me there've been examples of drivers that did return after some period of time to the "pre break-in/warmed-up" state. Not significantly perhaps....

 

[Verdinut]

Seems to me there've been examples of drivers that did return after some period of time to the "pre break-in/warmed-up" state. Not significantly perhaps....

IMO, that would happen with drivers which are driven over their normal operating limits and where there is no real break-in as such. If I remember well, didn't that happen once with @Pogre's tower speakers when he drove them a little hard?

 

[lovinthehd]

IMO, that would happen with drivers which are driven over their normal operating limits and where there is no real break-in as such. If I remember well, didn't that happen once with @Pogre's tower speakers when he drove them a little hard?

I think it was more about the surround used....while warmed up/broken-in and measured it showed a change...then a few days later was back to original state. Not like this is an issue.....

 

[Verdinut]

So would you conclude that this video is over exaggerating the effect of “break in?” If so, why?


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I already mentioned that break-in of drivers had a trivial effect on their performance and it's a waste of time except for loudspeaker builders.

Let me quote what Vance Dickason, an Audio Engineering Society member, in his "Loudspeaker Design Cookbook" wrote about break-in:

" Why bother to break-in drivers prior to testing? To assure that a valid test sample is being used. If a bad voice coil rub or poorly glued surround or spider are going to be a problem, banging the driver around with a reasonable amount of voltage at 25 Hz for 12 hours should reveal the flaw. There is no sense in proceeding to design a project if the woofer is not a representative sample."

 

[killdozzer]

I'm reading this thread closely and would like to add for the sake of precise arguments and hence conclusions.

There's a difference between burn-in and deterioration and I see you mix these terms occasionally.

This is deterioration, and what you talk about when you say magnets loose their properties, or materials become softer or entropy etc. This is not a case for "burn-in" crowd since no one here or in his right mind would ever make such a silly claim to say speaker never deteriorate and always sounds the same:

This is how burn-in would look like (although it should hold the peak for at least some time to be more accurate). Your unit under performs when new, you bring it to its level and after awhile it starts dropping.

To me personally, even making such a dubious claim that a company knows and calculates in where the performance will be after a 100 or 350 hours is just unacceptable.

You burn in your ear. Marketing uses this to make you go through the adapting period and stick with your choice (not claim for refund) by saying listen to it for some time while it burns in (for me dead give away is the fact that they always tell you not to let it play on its own while you're at work - of course, no owner's ear, no break-in).

It's very hard to notice the slow process of deterioration and most of us will notice it only when AB compared very old speaker to a new one. At this point we might even opt for the old one simply for habit and this is why brochure tells us to break-in the new gear. It happens all the time, after spending 200 or more hours with a new unit, there's no going back or hardly ever.

 

[Pogre]

IMO, that would happen with drivers which are driven over their normal operating limits and where there is no real break-in as such. If I remember well, didn't that happen once with @Pogre's tower speakers when he drove them a little hard?

I think you're thinking of when I put my grille on upside down and it deformed the surround. I've definitely driven them pretty hard, but not to the point where I noticed any physical or audible changes.

 

[Verdinut]

I think you're thinking of when I put my grille on upside down and it deformed the surround. I've definitely driven them pretty hard, but not to the point where I noticed any physical or audible changes.

Jason, I had forgotten about the grill installed upside down. Thanks for reminding me and clarifying the situation.

 

[KEW]

Burn-in is critical for speakers!
You get them home, with high expectations of a magical transformation and they don't deliver. Crap! You pack them up and haul them back to the store and the seller asks "Well, did you burn them in?" Accordingly you dutifully take them back home, set them up, and start the burn in (which is often over a week).
This is "a win" for the sellers. I'm sure there are studies out their, but it is so much easier to pack something back up and return it immediately than it is a week or two later. You can still return it, but I would bet my first-born that statistically, the likelihood of a return after the customer takes them back home is reduced significantly!
Thus, the value of proper burn-in should never be ignored ... my pet!
(you are being "game-ified"!)

Just in case there is any doubt, this post is riddled with sarcasm about the importance of burn-in.
I do think burn in (as used for home audio) is a profit-oriented concept which marketing departments encourage via owner manuals!

 

[Pogre]

Burn-in is critical for speakers!
You get them home, with high expectations of a magical transformation and they don't deliver. Crap! You pack them up and haul them back to the store and the seller asks "Well, did you burn them in?" Accordingly you dutifully take them back home, set them up, and start the burn in (which is often over a week).
This is "a win" for the sellers. I'm sure there are studies out their, but it is so much easier to pack something back up and return it immediately than it is a week or two later. You can still return it, but I would bet my first-born that statistically, the likelihood of a return after the customer takes them back home is reduced significantly!
Thus, the value of proper burn-in should never be ignored ... my pet!
(you are being game-ified!)

Not to mention it's that much more time for you to "break in" to the different timbre of your new speakers. You get used to and it becomes your new reference sound.

 

[mtrycrafts]

...

You burn in your ear. ...

Then, as you get older you burn it out.

Who complains about that?