Do Audio Speakers Break-in?

[ctrl]

This completely mirrors research performed at Harman where they tested a new woofer and a "broken-in" one in a real speaker. While physical changes are occurring in the driver, they are at such low level that there is no hope of attaching them to audibility.

Speaker break-in is very real and very measurable, but in most cases will still not be audible.

These statements are consistent with my experience.
A really good chassis or loudspeaker shows almost no measurable break-in.

To underline this, here is an example. On 12-2018 I finished and measured a bass compartment (called "Troll-Base") with the Dayton RSS390HF-4.

Today, more than a year later, I measured the bass compartment again (the chassis was definitely broken in over the year, because my 500W power amplifier is clipping regularly ).

First of all we look at the impedance curve with the new chassis/loudspeaker (yellow curve) compared to today (green curve).

It's nice to see that the resonance frequency of the entire loudspeaker has not changed at all. I wouldn't expect anything else from a really high quality driver and the RSS390HF-4 is one.

If you take a closer look you will notice slight changes in the range of 100-300Hz and around 800Hz.


Next we look at the near field frequency response of the new chassis/speaker compared to today.

Since the "Troll-Base" is responsible for the low frequency response in several possible 3-way combinations, a range of use up to 300Hz (maybe even up to 500Hz) is planned. (new chassis/loudspeaker - yellow curve, measured today - red)

If the chassis would be used as pure sub-woofer, there would be no change at all.

In the free field with the influence of the driver cone and the baffle of the loudspeaker, a small change around 220Hz might still occur. Will this change be audible? In this frequency range rather not (in addition, in many living rooms the Schroeder frequency is around 200Hz, so room modes further reduce audibility).

So a speaker that sounds like crap will not mutate into a high-end miracle even after 100 hours of use - send it back.

 

[Hiten]

Why would any speaker company use materials that would give discernible change in sound or response after hours of playing ? If they use materials that change after few hours chances are they would further change or probably deteriorate. But speakers are made to last atleast few decade. So reasonable thinking would be that they may make subtle changes which can be cheerfully ignored by majority of people.
How much response, distortion and resonance changes would be nice to see though.
Regards

 

[BurgerCheese]

I always assumed that the break-in was to allow the brain to forget whatever you had before. People tend to get used to what they have. Then in true audiophile tradition this must be explained in some silly way, lots of audiophiles will be offended if you tell them the truth on how the brain works.

There are measurable changes to stiffness of suspension, etc but I have never heard any differences in a finished speaker. I make my own speakers and usually make one speaker, mess around with the crossover until I'm happy then I make another one (or 10 in these Atmos days). I can't tell the first and the second speaker apart even though the first one was used for countless hours and the second one had pristine new parts. I guess I could do a blind test next time.

 

[Andreas007]

Coming from a material science background:
Especially plastics/polymers have some properties which are quite interesting and support the break-in theory.

Take the rubber suspension ring for example: The polymer chains in a rubber network are chemically cross-linked. Nonetheless, the polymer chains in this network can re-arrange to a certain degree when stressed repeatedly. Depending on the used rubber the result of this re-arrangement can be a lowered Youngs modulus (softer) and reduced storage modulus. A first stress of a newly vulcanized rubber part will definitely change the material properties in some way. How much? This will depend on amount/type of stress, part design and type of rubber used.

But, more important question should be: How and to which extent does this have an impact on the final sound of a speaker?
I guess it's neglible, perhaps with the exception of woofer performance where it can be measured and heard (?).

Did you ever buy an abysmal sounding speaker (then I would wonder "why?") which then miraculously transformend into a high end speaker? I also wonder why everyone thinks that break-in leads to a "better" speaker - could be the other way around, too. Assuming this is a big effect and manufacturer doesn't care...

For me it comes down to this: The more a speaker needs "break-in" time the less a manufacturer cares about material choices and end customers. Take the green banana it will become yellow over time!

 

[hardisj]

I tested speaker break-in a couple times over the years. I tried to dig up my data but can't find it. What I do recall was some difference in one of my test subjects and I seem to recall a measurable difference in THD. But I'll have to dig hard to find the data. :/

Alas, what really matters is the duration and drive level. I can test a speaker after BEATING on it and get different T/S parameters than I did initially. Then I let it cool off a bit, and re-test with the same initial drive level and the results are much closer to the initial result. I'm NOT saying break in doesn't cause drivers' spec to change slightly. I am saying that test conditions matter more than break-in period.

 

[anmpr1]

Whenever I get a new speaker I first eliminate any electro-mystic interference by wrapping the entire structure in several layers of tin-foil. Pie pans are good for covering the actual cones. Make sure and cover all the baffles, front and back box, etc in order to eliminate any unwanted interferance.

Next, play your Tibetan Yak-bak speaker break-in test disc (analog 180g vinyl-not the DDD hi-bit version--$200.00 direct from Absolute Hi Fi News and Stereophile Sound) at varying volumes for at least a couple of days. It is important to reverse polarity of the speaker wires half-way through the protocol.

After two or three days you should then unwrap the speaker. When you first begin the test you will find that the sound is very muffled. However, after a couple of days of burn-in, and once you unwrap the several layers of aluminum foil from around the box, baffles and drivers, you will absolutely tell that the speakers sound much clearer and cleaner. So break in is an important thing to do provided that you do it correctly, and have the right tools for the job.

 

[hardisj]

Also, the engineers I’ve talked to about subwoofer testing have recommended feeding the DUT a test tone at Fs for a couple hours to make sure the drive unit is “loose”. Their reasoning is that items made in the factory and slapped in a box need a little bit of time to break in the glues/spider. Again, not my words. Just sharing some insight.



Personally, I do feel that if there were to be a measurable change that a few sine sweeps isn’t the way to check for it. I wouldn’t expect low level sweeps to really exercise or “loosen up” the suspension in an appreciable way. Why? Because, I can absolutely tell you, that in some cases (not-so-good drive units) even the Fs and Qts can shift a good bit with excursion. Need proof? See the attached Klippel report I created from the Peerless HDS 8 inch midwoofer and the below photos from said report. A low level sweep isn't going to move the driver as much as a high output signal.

So I wouldn’t consider the “myth” debunked until further testing is done. Like I said, I did have different results with measurements once a driver was fed a signal for a period of time. I’ll try to dig that up tonight if I can. If not, then I’ll post my results.

 

[carlob]

Alan Shaw, Harbeth owner and designer:

"Actually, the real situation is pretty basic stuff. The (usually) yellow suspension ring hidden under the cone, called in the trade the spider, is nothing more or less than resin impregnated woven fabric.

When flexed a few times, the sheet of resin presumably takes on micro fissures, and once that process has occurred - over perhaps the first few hours or so under normal home use, accelerated in the test lab by playing very loud - the fundamental resonance frequency of the woofer drops by a few percent (utterly inaudible, difficult to even measure) and that's it, forever. Any perception that the sound has subjectively improved after hiours, days or weeks is entirely and totally in the listener's imagination. They may well truly believe that, buit it is nothing more than familiarisation, a very common human experience. When I changed car recently I was amazed at the ride, the power and the handling. Two weeks later, it all seemed perfectly unremarkable to me."

 

[SimpleTheater]

Conclusions
Objective analysis shows that there is no change to the frequency response and hence tonality of the speaker after a few hours of intensive running (full sweeps from 20 to 20 kHz). This completely mirrors research performed at Harman where they tested a new woofer and a "broken-in" one in a real speaker. While physical changes are occurring in the driver, they are at such low level that there is no hope of attaching them to audibility.

First, I'd like to let everyone on this site how lucky they are to have me bring real objective facts to these discussions.

Second, please note Amirm is misreading what Klipsh and other speaker companies are saying because those instructions are written for the average consumer, who can't be expected to understand what they are doing. In Klipsh's defense they are making the assumption that when you buy your first set of speakers, you're also probably buying your first set of speaker cables. It is the CABLES that need to be broken in.

Here is an objective, fact based link everyone should memorize from Moon Audio:
https://www.moon-audio.com/audio-cable-break-in-time

Speaker cables need 40 hours of break in, and Moon Audio says NOTHING about speakers, because they do NOT need break in. Klipsh simply can't risk that a buyer understands the difference between breaking in their speakers or breaking in their cables, so they cover both by simply saying to break in the speakers.

So in Amirm's test results, since he was using BROKEN IN cables, objectivists like myself never expected there to be a difference.

This is basic science I'm trying to convey here, so please don't take my "I'm better than you" attitude negatively. I'm just trying to teach you the nuances in writing effective user manuals.

 

[jtwrace]

Coming from a material science background:

Should I volunteer to do all the rubber surround tensile & LCF testing? I've always been under the premise that drivers really "break-in" after about 5 min of moving hard to "stretch" the materials. It's like a tensile test without reaching yield.

 

[thewas]

Wasn't Moon Audios recommendation of breaking-in cables in for 14 days listening to Pink Floyds Dark Side of the Moon at the correct of course moon phase?
Since then my Klipsh sound smooth and more like a Klipsch.

 

[BurgerCheese]

Should I volunteer to do all the rubber surround tensile & LCF testing? I've always been under the premise that drivers really "break-in" after about 5 min of moving hard to "stretch" the materials. It's like a tensile test without reaching fracture.

I'd assume that most of the "stretching" is done at the factory during quality control. At least for those manufacturers that do a proper QC.

 

[ctrl]

So in Amirm's test results, since he was using BROKEN IN cables, objectivists like myself never expected there to be a difference.

... and since no one has yet broken in(to) his garage, all measurements made there should be taken with caution.

 

[Lavawood]

I recently changed the drivers on a pair of Dynaudio Contour 1.3’s (1997). The first time I played music I got goosebumps. It had been 2 years since I took them out of service. The drivers Dynaudio delivered could have been newly minted or had been on a shelf for a decade, I don’t know. I noticed the sound was thin at lower volumes and I can say that now, a few hundred hours later, they are more dynamic at these levels. Another difference, they are just louder and faster at these lower levels. In other words, they require less power for a given output. Would a frequency sweep show this? I think a burst test like I saw in another thread might. Comparing the input to the actual output and observing the difference. Is it unreasonable to theorize a driver would require less power to accelerate over time until it’s “broken in”?

all measurements were performed utilizing 50 year old test gear afflicted with a bit of tinnitus.

Edit:
Did I expect them to be stiff?, yes
Did I expect them to break in and sound better?, yep
Did I change power tubes during the last month? Mmhmm

 

[jtwrace]

I'd assume that most of the "stretching" is done at the factory during quality control. At least for those manufacturers that do a proper QC.

One would think. I know JBL does as I've been there...

 

[Ron Texas]

I have never heard any difference between right out of the box and a few days later.

 

[hardisj]

I think this thread can be boiled down to:
Do speakers break in? Depends.
Does it matter? Depends.


Your result always depends on your test methods.

In this case, the test method showed no difference. I've conducted tests that show a difference because I used a higher voltage and pushed the driver to further excursion. The real question is: does the break-in matter. I've seen evidence showing the net result is likely inaudible. I'm OK with that conclusion. If there is a serious shift in audible performance then that's a problem. I have yet to encounter such a case.

 

[hardisj]

From a well-respected drive unit manufacturer:
https://www.eminence.com/speaker-break-in/

Speaker break-in is no myth and something significant really does happen. All speakers are built to meet certain specifications, and we work diligently through QC efforts during and after production to ensure that happens. Every component used in a speaker has tolerances, which can relate to small variances in initial performance. The mechanical properties of a speaker are slightly modified once a speaker is put into service, and the tone is affected by these changes. Speaker break-in is a natural process that is influenced by how much you use the speaker and how loud you play it. Think of a new pair of shoes. They are not most comfortable right out of the box. They feel best after you have worn them for a while, softened up, and formed to your feet. Much like your new pair of shoes, new speakers need time to “break in”, and will not sound best until they do.

The components making up the speaker’s suspension are primarily what changes during break-in. These components are the spider (lower suspension) and the cone surround (upper suspension). As the speaker is used, the spider and cone surround begin losing some of their initial stiffness. The sonic results you will hear are an increase in overall warmth, slightly deeper/fatter lows, and warmer/smoother highs. Subtle changes will continue throughout the life cycle of the speaker, but the most noticeable amount occurs in the early stages of use.

The duration of time required to achieve break-in will vary between speakers. Your environment can affect speaker break-in as well. It may take longer in a cold, dry climate versus a hotter, more humid environment. Again, your usage and volume will also affect break-in time. There are several methods people use to speed up the process, but these methods can be damaging to the speaker and are not recommended. The best method is to simply play your new speaker at normal to high volume as frequently as possible. You may even find it is fun and enlightening to experience the changes in your speaker as it breaks in!

 

[headshake]

IMO the psycho-break-in is just sensory adaptation.

"Sensory adaptation refers to a reduction in sensitivity to a stimulus after constant exposure to it. While sensory adaptation reduces our awareness of a constant stimulus, it helps free up our attention and resources to attend to other stimuli in the environment around us"

The end.

 

[hardisj]

My take...

I believe in some cases break-in occurs. There's variables at play (QC, pre-testing, drive levels, etc).

The thing is, though, assuming the drive units are from a reputable manufacturer and are expected to perform within a design tolerance, why not just hook the speakers up to some test signal for some period of time, turn them up to a hefty output but not distressing them, and let them run for a bit. Then you've done as some manufacturers suggest. There's no harm in doing this.