Do Audio Speakers Break-in?

[MAB]

I have a brand new woofer that I got as a replacement, the original was defective.

The replacement driver has been sitting around un-played. Seems like it is time to see how it changes with 'break-in'.

I got a DATS recently, so I'll use that. I did check it against an HP LCR with a bias adapter and frequency generator, it is fairly accurate and less cumbersome (although I still have a Macintosh IIfx and with a National Instruments GPIB bus card and LabView that I can fully automate the old HP with...) But, I'm not looking for tiny signals so lots of simple test fixtures should work. I do think FR and distortion measurements might be a good addition, since many of these break-in mechanisms that are posited here seem that they would also be accompanied by distortion (like changing plasticity of parts). But this is a pretty boring experiment, where I really don't expect to change the world, so the distortion measurements will have to wait!

I did about 50 measurements, first to try to establish a baseline, then to see how temperature might change the measurements, followed by a 30 minute stress to see if the driver breaks in.
Group 01 I measured the driver right out of the box (the red dots).
Group 02 The heater came on, so I made ten more measurements over the next half hour while the heater gently blew hot air into the room (green triangles). Note, the heater went from low to high fan speed after the third measurement in this test.
Group 03 The heater goes off, and I keep recording measurements.
Group 04 I used a fan to blow a gentle breeze over the driver.
Group 05 I put the driver in the fridge for 10 minutes.
Group 06 1 hour after the fridge.
Group 07 20 more mins in the fridge.
Group 08 Warming for 2 hours after the fridge while taking measurements. Break-in is next.
Group 09 Right after 30 mins 30 Hz Break-in while driver is tangibly warm.
Group 10 Cooldown for 2 hours after the break-in while taking measurements.
Group 11 Let speaker rest overnight after break-in.

I wanted to see if the DATs signal is large enough to induce some sort of break-in. Whatever the impact of the small DATS test signal, I discovered the heater is a larger effect that that.
Also, the driver tests much different than Seas' spec in almost all parameters, I guess I'm not surprised since few manufacturers produce drivers and spec sheets that align. Even top of the line Seas and Scan-Speak drivers deviate. In my limited experience, JBL are the closest to published spec, and seem to have the best unit to unit matching. Seas are not very close, although I can't hear the matching issues and whatever the parameters are, the drivers are great... I certainly have lots of them for some reason...

From the measurements with and without heater, looks like room temperature variation is worth about 0.6% F(s), 1.3% Q(ts), 1.2% Q(es). The Q(ms) story is interesting since Q(ms) seems to be affected by the breeze from the heater vent. So does wind from a hand-held fan, which makes sense. I am surprised the airflow from the vent on the opposite side of the room had such an impact, but after thinking about the sensitivity of microphones in general, even a speaker should be quite sensitive to a breeze! Good thing I tend to play music louder than my heater so the impact of random air currents on the effective Q should be negligible! L(e) and R(e) are unsurprising.

I fully expected large changes in parameters after chilling in the refrigerator. I didn't expect it to take more than 2 hours to recover. I wonder if it would fully recover, or if it has some plastic hysteresis that would require large motion to change. The R(e) measurements show it certainly has not come back to equilibrium temperature. In any case, I ran out of patience and decided to move on to break-in stress.

I gave the driver a break-in stress of 30 Hz at 80% or so of maximum. After the break-in stress, the driver was noticeably warm to the touch. After 10 or 15 mins I could no longer tell it was warm. After 2 hours of cooldown, the driver seemed to stabilize, remeasuring this morning (in a cold room) after letting the driver sit overnight confirmed this.

After the overnight rest, F(s) dropped by 1.3% from T=0 value, some of that is likely the cold temperature in the room this morning. Probably closer to 1% after controlling for temperature; that's not much. Seas driver to driver matching is worse than that (more on that in a bit). Q(ts) drops by 2.2%, Q(es) by 1.4%, and Q(ms) by 3.5%, some of these changes are likely temperature.

Regarding driver matching, I have a pair of similar Seas drivers (actually the first version of these W18 woofers). The unit that I am breaking-in here is the second version, they are different drivers with somewhat different FR and T/S parameters:

Despite that, I am hard pressed to hear the actual differences between v1 and v2 under normal use. The easiest way for me is to do a sweep on the two drivers with no filters and listen for the different tone of that big resonant peak when the cone breaks up above 4 kHz, they actually have a different timbre as the sweep runs through that resonance. I can hear it on different precision tracks if I remove the notch filter I normally use with these drivers. Other than these corner cases, both versions sound awesome when used with an crossover, with a notch filter at the resonance.

Here's the unit matching between the two well-used W18 v1 drivers I have, mounted in identical sealed enclosures (not free-air!!!)

R(e) is well-matched, which I expect for two (hopefully identical) lengths of wire at the same temperature. The rest of the parameters are all over the place. Winding the wire into a voice coil has so many geometric considerations, no surprise 3.5% difference. Same for all of the plasticy and bendy things that conspire to make the mechanical bits and pieces, I am not surprised at this level of mismatch in F(s) and the Q measurements, it is very common even if I can't hear the differences in use. I actually have no idea how the JBL drivers I used to measure were so consistent, like better than 1% for these electromechanical parameters.

Whatever happened in the first 30 minutes of stress last night on the new driver is way less than the driver to driver matching I get between samples. I'll subject the driver to more stress today. See if anything changes.

 

[MAB]

Yep, that's what u burn-in period (at least for electronics) are good for.
Sifting out units that would fail rather sooner than later. This what I use the word 'burn-in' for and use the word 'break-in' for mechanical devices that are not meeting specs yet when rolling off an assembly line.

Agreed, they are different. Burn-In is a manufacturing quality screen to capture early-life fails, Break-In is something a consumer experiences with certain new products.

Quite common in the non consumer world to do this.
This, however, is as you state no guarantee the device will have good longevity and quality.

200Hrs or 1000 hours to get 'maximum sound quality' is nonsense and IMHO just something manufacturers/sellers use to state to get people to 'adjust' to devices they had high hopes for but initially don't seem to deliver.

Double-agreed. I read about people running speakers at near maximum excursion for a day or two to 'break-in' a new driver. At that use condition, the risk is wearing it out.

 

[cavedriver]

R(e) is well-matched, which I expect for two (hopefully identical) lengths of wire at the same temperature. The rest of the parameters are all over the place. Winding the wire into a voice coil has so many geometric considerations, no surprise 3.5% difference. Same for all of the plasticy and bendy things that conspire to make the mechanical bits and pieces, I am not surprised at this level of mismatch in F(s) and the Q measurements, it is very common even if I can't hear the differences in use. I actually have no idea how the JBL drivers I used to measure were so consistent, like better than 1% for these electromechanical parameters.

Which raises the question unrelated to speaker break-in of whether speaker manufacturers do enough to match drivers. Snell used to test each driver and match crossover components to them and then match the entire speaker to a reference speaker. I'm sure better manufacturers do this today, but which don't?

But staying on topic, which of the parameter changes you observed above might produce an audible difference? As you mentioned you did not do freq resp and distortion measurements, which is where we would hope to get directly at whether they have any "hearable" difference. I think the person that does driver bench testing for audioxpress.com and Voicecoil (Vance Dickason, possibly others?) seems to be getting to a level where they would also detect any measurable differences. here's one of his reviews where he had two copies of a Seas W18EX003 driver, but with a quick skim I didn't see where he ran both units through any of the mic'd tests and compared their performance:

Test Bench: SEAS Excel Graphene W18EX003 6.5” Midbass Driver

On this edition of Test Bench, Vance Dickason continues to measure one of the most anticipated driver designs launched in the market in 2019, from SEAS's new Excel Graphene line. Following the previous Test Bench on the W16NX003 5.25” midbass woofer, this one focuses on the W18EX003 6.5” midbass...

audioxpress.com

 

[MAB]

Which raises the question unrelated to speaker break-in of whether speaker manufacturers do enough to match drivers. Snell used to test each driver and match crossover components to them and then match the entire speaker to a reference speaker. I'm sure better manufacturers do this today, but which don't?

But staying on topic, which of the parameter changes you observed above might produce an audible difference? As you mentioned you did not do freq resp and distortion measurements, which is where we would hope to get directly at whether they have any "hearable" difference. I think the person that does driver bench testing for audioxpress.com and Voicecoil (Vance Dickason, possibly others?) seems to be getting to a level where they would also detect any measurable differences. here's one of his reviews where he had two copies of a Seas W18EX003 driver, but with a quick skim I didn't see where he ran both units through any of the mic'd tests and compared their performance:

Test Bench: SEAS Excel Graphene W18EX003 6.5” Midbass Driver

On this edition of Test Bench, Vance Dickason continues to measure one of the most anticipated driver designs launched in the market in 2019, from SEAS's new Excel Graphene line. Following the previous Test Bench on the W16NX003 5.25” midbass woofer, this one focuses on the W18EX003 6.5” midbass...

audioxpress.com

Sensitivity, which I didn't measure, because of all the things I have seen change I have never seen a driver's sensitivity change.
I've thought about this matched driver and crossover component thing. Years ago, I worried. The first really nice DIY I built, I matched the drivers, the crossover components, etc. I quickly discovered I could barely measure the differences in the speakers and crossover components, let alone hear them in real world use. I also found out I couldn't measure or hear the differences between the massively expensive crossovers that weighed 10 kilos or ones made from cheap parts that weighed and cost 100x less:

So I'm not too worried about the actual mismatched driver issue. I listen to those speakers every day and cannot tell for the life of me that one has parameters that are ~5% different than the other.

I imagined that the tighter tolerances I measured on JBL were due to they were designed with massive thermal capabilities and the tolerances required make for great unit to unit repeatability. And they certainly charge for it! I am sure other companies have similar matching. I am not sure it is always driven by audibility under normal home listening, but rather they need to handle continuous high power and the associated tolerances. I think Seas et. al. allow this level of unit mismatch because we can't hear it, presumably they worked on the things we can actually hear. And manufacturers love to talk about hand matching components because that helps to justify their product, kind of like Corinthian leather.

 

[YSC]

Agreed, they are different. Burn-In is a manufacturing quality screen to capture early-life fails, Break-In is something a consumer experiences with certain new products.

Double-agreed. I read about people running speakers at near maximum excursion for a day or two to 'break-in' a new driver. At that use condition, the risk is wearing it out.

Completely agree with it, the warming up and environmental changes affect the speakers a lot more than the “break in” do, differences are just more on inaudible minute change which day to day variances will overwhelm it, if breakin will be an issue, a windless temperature and moisture controlled room will do a lot more

 

[Deleted member 48726]

Agreed, they are different. Burn-In is a manufacturing quality screen to capture early-life fails, Break-In is something a consumer experiences with certain new products.

...

No. I believe the difference lies in mechanical vs. electronical.

 

[Deleted member 48726]

Completely agree with it, the warming up and environmental changes affect the speakers a lot more than the “break in” do, differences are just more on inaudible minute change which day to day variances will overwhelm it, if breakin will be an issue, a windless temperature and moisture controlled room will do a lot more

I think it is wise to rephrase what you just wrote to not be as generalizing and conclusive. This is a (singular) test, albeit absolutely great work by @MAB , on a small woofer. It shows changes. Other drivers show less or more. I'm certain larger woofers for example will show much larger values. -That's my non-documented experience.

 

[JktHifi]

Probably the manufacturers want us to test their product after we purchase it. Test it until break so warranty claim easier at the first day we purchase. It is mentioned as break-in so let’s break the product.

 

[Deleted member 48726]

Sensitivity, which I didn't measure, because of all the things I have seen change I have never seen a driver's sensitivity change.
I've thought about this matched driver and crossover component thing. Years ago, I worried. The first really nice DIY I built, I matched the drivers, the crossover components, etc. I quickly discovered I could barely measure the differences in the speakers and crossover components, let alone hear them in real world use. I also found out I couldn't measure or hear the differences between the massively expensive crossovers that weighed 10 kilos or ones made from cheap parts that weighed and cost 100x less:

So I'm not too worried about the actual mismatched driver issue. I listen to those speakers every day and cannot tell for the life of me that one has parameters that are ~5% different than the other.

I imagined that the tighter tolerances I measured on JBL were due to they were designed with massive thermal capabilities and the tolerances required make for great unit to unit repeatability. And they certainly charge for it! I am sure other companies have similar matching. I am not sure it is always driven by audibility under normal home listening, but rather they need to handle continuous high power and the associated tolerances. I think Seas et. al. allow this level of unit mismatch because we can't hear it, presumably they worked on the things we can actually hear. And manufacturers love to talk about hand matching components because that helps to justify their product, kind of like Corinthian leather.

I'm missing the banana for scale, but still this crossover looks massive. -What monster was that going in to?

 

[MAB]

Seas Thor.

SEAS The Art Of Sound Perfection

THE ART OF SOUND PERFECTION BY SEAS

www.seas.no

Those North Creek inductors are slightly absurd.
I later converted them to various active iterations ending with full DSP. I also built them into larger transmission lines.

 

[Deleted member 48726]

Seas Thor.

SEAS The Art Of Sound Perfection

THE ART OF SOUND PERFECTION BY SEAS

www.seas.no

Those North Creek inductors are slightly absurd.
I later converted them to various active iterations ending with full DSP. I also built them into larger transmission lines.

Oh, nice one. Always liked the Excel drivers. But the crossover still looks to be on the far far safe side of power handling capabilities IR to the drivers used in the speaker.

 

[YSC]

I think it is wise to rephrase what you just wrote to not be as generalizing and conclusive. This is a (singular) test, albeit absolutely great work by @MAB , on a small woofer. It shows changes. Other drivers show less or more. I'm certain larger woofers for example will show much larger values. -That's my non-documented experience.

well I don't think it's wise to just insist on breaking in is a real issue or thing with every single test being a "single" and "exceptional case", toole's controlled tests on audibility and their engineering department believes no meaningful/audible change at all and not surprised, only marketing ppl are surprised and note in that conclusion by Dr Toole, there IS some minor change in 30-40hz region being measurable as expected, just not changing in sound percieved in controlled tests.

For larger woofers with more mass and stiffer suspension, sure the initial burn in or wear out will result in more change in material or single parameter, but so as temperature and moisture do, unless every single component is made of exactly the same material, differential expension and contraction with temperature will exert more internal friction etc. to the assembly, and warming up do change rubber behaviour a lot (tyres on winter vs summer, or even car tyres warm vs cold from garage is a more extreme example) than the flexing will do to wear and tear from "break in".

It seems wiser to me that to believe in the effect of breaking in until there are a few measurable test showing that the change in parameter (e.g. FR, distortion, decay time etc.) to be more than unit to unit variation between drivers, and the change in temperature do to the driver. In that way at least I don't risk accelerating the unnecessary wearing down of the drivers and breaking the speakers earlier.

ASAIK in science training, you can only proof what DO EXIST, not vice versa, thus far I didn't see any study or even self test using the same driver, in a meaningfully controlled way like @MAB did showed that running in affects the driver more than domestic daily fluctuation in temperature, moisture and air flow, let alone be it an audible case as in blind test

 

[Deleted member 48726]

well I don't think it's wise to just insist on breaking in is a real issue or thing with every single test being a "single" and "exceptional case", toole's controlled tests on audibility and their engineering department believes no meaningful/audible change at all and not surprised, only marketing ppl are surprised and note in that conclusion by Dr Toole, there IS some minor change in 30-40hz region being measurable as expected, just not changing in sound percieved in controlled tests.

For larger woofers with more mass and stiffer suspension, sure the initial burn in or wear out will result in more change in material or single parameter, but so as temperature and moisture do, unless every single component is made of exactly the same material, differential expension and contraction with temperature will exert more internal friction etc. to the assembly, and warming up do change rubber behaviour a lot (tyres on winter vs summer, or even car tyres warm vs cold from garage is a more extreme example) than the flexing will do to wear and tear from "break in".

It seems wiser to me that to believe in the effect of breaking in until there are a few measurable test showing that the change in parameter (e.g. FR, distortion, decay time etc.) to be more than unit to unit variation between drivers, and the change in temperature do to the driver. In that way at least I don't risk accelerating the unnecessary wearing down of the drivers and breaking the speakers earlier.

ASAIK in science training, you can only proof what DO EXIST, not vice versa, thus far I didn't see any study or even self test using the same driver, in a meaningfully controlled way like @MAB did showed that running in affects the driver more than domestic daily fluctuation in temperature, moisture and air flow, let alone be it an audible case as in blind test

Well, this is what you stated, and it is generalizing, no?
You can't conclude that climatic changes always will have larger effect than break-in. Especially when the referred to environmental changes is done in the extreme (freezing driver etc.)

And when you can't conclude it, it is wrong stating things in generalizing terms like you did here-->

Completely agree with it, the warming up and environmental changes affect the speakers a lot more than the “break in” do, differences are just more on inaudible minute change which day to day variances will overwhelm it, if breakin will be an issue, a windless temperature and moisture controlled room will do a lot more

I agree that every test should not be dismissed as exceptional or deviant. Other wise every review and test can be dismissed as well without batch testing.

 

[YSC]

Well, this is what you stated, and it is generalizing, no?
You can't conclude that climatic changes always will have larger effect than break-in. Especially when the referred to environmental changes is done in the extreme (freezing driver etc.)

And when you can't conclude it, it is wrong stating things in generalizing terms like you did here-->


I agree that every test should not be dismissed as exceptional or deviant. Other wise every review and test can be dismissed as well without batch testing.

break in as an effect itself is generalizing, nothing specific, point is that

1) freezing vs 20C isn't that much of a change, in a lot of places in winter, internal room heating on vs off already get that
2) everything changes in parameter after some initial burning in, but never settles on exact spot, the changes continues so as the environment

so until seeing some controlled test/ measurement showing a change significant enough to be audible, and yet it don't just roll back a day or two later as in @MAB's tests, it just can't get my mind to believe it's a meaningful change other than something that "you won't notice", when the change can't be demonstrated to be significant enough to be detected and which the property stays there after run in, it really don't make sense to even bother with the process to go through.

Thus far it don't seems to really have any practical measurable change shown here or google search, as someone stated before, using a well run-in unit vs a brand new unit don't count, the unit to unit variation is quite often than not, much larger

 

[egellings]

Try again. -With the reading that is. Not the gnarly remarks. Seems like you really can't control those.

For a self-titled objectivist you sure use a lot of subjective and emotional guided words and phrases. -Unwarranted insults, generalizations, bets.


-Sounds like something a reptile would say.

Reptilian mentality: If it's larger than me, run; if smaller, swallow it.

 

[valve_integrator]

I have a brand new woofer that I got as a replacement, the original was defective.

This is all a bit dumb.
The speed of sound changes with temperature.
The main reason why A440 was eventually decided on, was because concert halls started to be heated from the 1930s on.
Just see what happens if you heat up a wind instrument...
'nuff said.

 

[MAB]

This is all a bit dumb.
The speed of sound changes with temperature.
The main reason why A440 was eventually decided on, was because concert halls started to be heated from the 1930s on.
Just see what happens if you heat up a wind instrument...
'nuff said.

No idea what is all dumb. Maybe I missed your point.
Yes, my clarinet does change pitch with temperature, but not because of the same physics that causes a speaker changes electrical behavior with temperature.
But, clarinets, concert halls, and speakers do share one thing in common; they do not appreciably break-in. And temperature changes (for instance) are much larger impact on the sound than so-called break-in.
Maybe that was your point.

 

[DonH56]

No idea what is all dumb. Maybe I missed your point.
Yes, my clarinet does change pitch with temperature, but not because of the same physics that causes a speaker changes electrical behavior with temperature.
But, clarinets, concert halls, and speakers do share one thing in common; they do not appreciably break-in. And temperature changes (for instance) are much larger impact on the sound than so-called break-in.
Maybe that was your point.

Reeds? I play trumpet, but reeds seem to have "break-in" issues. Especially double reeds. The clarinet itself, not so much...

Also struggling to see what A = 440 Hz has to do with break-in, however...

 

[MAB]

Reeds? I play trumpet, but reeds seem to have "break-in" issues. Especially double reeds. The clarinet itself, not so much...

Also struggling to see what A = 440 Hz has to do with break-in, however...

Yeah, after all the stuff we do to our reeds prior to playing. Don't even get me started on the back art of double reeds! I am sure reed break-in is absolutely measurable; it's a piece of wood that is now impregnated with your spit. But I am not sure it can be called break-in. It's gonna weigh different, I have no doubt it's mechanical properties have dramatically changed after I slobbered on it. I'm not sure wetting a piece of wood with spit to get to work is the same as break-in. I require my speakers to not need me to spit all over them, and if I did I am pretty sure I could measure the changes.

Perhaps the post is just reinforcing that Temperature is a really big deal in sound and acoustics for a variety of reasons. That was the point of my measurements; whatever is happening T is a bigger deal in normal operation and needs to be controlled if you wish to do meaningful measurements. Someone here insisted that speakers break in dramatically, referencing an article where someone 'broke in' a Dayton midbass driver. The measurements of the Dayton changed dramatically, including some really suspicious things like large changes in DC Resistance. It was clear to me that this 'evidence' of break-in was actual a hot driver, or they just messed up the measurement in more dramtic fashion. So I assume the point being made is; Temperature matters.

I will say this, after looking through 69 pages of this thread, there are only a few people willing to post data, and they have all been showing that drivers do not appreciably break in. Lot's of people have weighed in with their anecdotes about driver break-in. Some of the usual suspects are saying multiple dB of difference post-break-in. This is totally absurd if you think physically about what would need to happen to get 3dB of energy through a break-in procedure. Car analogies followed, and outside of F1 engines, I would be super bummed if a new Caterpillar diesel had the equivalent of a 3dB change in output due to the bits and pieces bedding in as they slide back and forth against each other. I say this because I used to repower boats, and Caterpillar would provide a break-in report for each new install we did. And I don't expect drivers to come even close to mechanical break-in of an engine. And of course we get the usual manufacturer spec sheet trolling. GR Research of course says speaker are essentially unlistenable until broken in, no surprise! And we have legions of audiophiles who refuse to listen to their hifi during break-in. And some who spend big money on break-in enhancing products. And anybody who had to turn down their subwoofers by 3dB after their perceived break-in are fooling themselves. I installed car stereos for years. Customers typically left with bass set on hero setting, despite my advice. Most would come back a week or so later saying "bro, my bass needs a final tune after it broke-in, bro!". The only thing that broke in was their sensibilities.

So yeah, Temperature combined with uncritical listening and no measurements is what gets us the pseudo-science of driver break-in. I think if someone really thinks drivers break in, and especially if they think they gonna get multiple dB change, they should test their hypothesis and post the data and conclusions. It's actually an easy test, if a bit boring. Otherwise people are just hijacking a thread.

 

[DonH56]

Humidity also affects the speed of sound as a first-order effect IIRC but is rarely mentioned...