Driver breakin period, what’s the science?

So have these new speakers and been told they need a hundred hours to be broken in, and then sound will improve.

What’s going on as break in occurs?  More important for tweet, mid or bass?  
My initial listening has simple vocals/music passages sounding very good, and more complex and very layered sections that may have potential to improve.  
Almost all the break-in occurs, at reasonably loud volume, in the first 5-10 minutes. If you still hate them after that period of time, then you hate them, though keeping them will cause your brain to change far more than the speakers.

However, changes in mechanical compliance of the structure can keep occurring for 5-10 hours. After 10 hours, not much.
The changes are measurable.  As the suspension breaks in, you can measure a difference in QMS and typically a bit In FS and QTS.  The biggest difference in sound definitely occurs in the first 45 minutes of played at a decent volume. (I'm not one to recommend real cranking), but I can tell you that the nuances of a speaker continue to change for at least a couple hundred hours.  
significant difference

components in the crossovers, driver surrounds esp mids and bass

the better the speaker and the more resolving the system is, the more this can be noticed, happens over the first 100 hrs at least... for mine, changes were noticeable up for 300-400 hrs...

this is significant... those who say no just don’t know...
its not about loudness changes, but about loosening up of sq.

I think better resolution and clarity in more complex areas of music is what happens as driver mechanism loosens up.  Very stiff up front my guess.
Heavy, high excursion butyl rubber surrounds, and stiff spiders (springs), they take a while to loosen up. To sound clean and go DEEP, 50-100 hours (over night on a tone generator)

I have GR servos. LOL took a couple of hours to hear them and all night to loosen up enough to hear well.. Weirdest thing I ever seen.. Like magic. I though they were broke. They were moving but, no sound. I think it had to do with the correction side of the driver, and the servo amps.

Lighter foams and springs, less time. 20-50 hours..

I’ve seen teflons caps in XO take a 200-300 hours too. The drivers were broke in long before the caps were.. Sound wonkie as all get out.. for a while.. Ear bleeding stuff, mercy.

Spiders a few minutes, surrounds  few hours. I doubt it's anything audible. Mostly you getting used to them, keep listening and forget about break-in.
the better the speaker and the more resolving the system is, the more this can be noticed, happens over the first 100 hrs at least... for mine, changes were noticeable up for 300-400 hrs...

this is significant... those who say no just don’t know...

One of my business partners would beg to differ having done extensive work on cone materials and cone breakup which required extensive testing of drivers to determine where parameters stabilized including high speed surface imaging and laser interferometry.

So have these new speakers and been told they need a hundred hours to be broken in, and then sound will improve.

This statement above is total crap. It does not take 100 hours to "sound good". There will be subtle changes after hours of reasonable volume. No magical major improvements after that. The only thing that happens by 100 hour is you got used to them.

w.r.t. Capacitors, electrolytics if they have been sitting can have a parameter change over a period of time, mainly in DC parameters, but you don't see those too much in high end speakers. Film capacitors are very stable is why they are used. There are people who have equipment and can test these things to significant accuracy. They are not the people making the claims. We can't measure how humans will perceive change, but we can measure if there is change.

A guy named Mike Samra, red sock green sock guy. Told me that teflon caps break in because of the DC, yet the speaker's VC would fry with it.. 

If it takes DC to break in a teflon cap, I still haven't figured how they breakin, in an XO, but they do. They sound bad (TRT) expensive caps too. Very harsh, highs will blister your ears, mids are veiled. They didn't effect the bass because there is no caps in a 6db first order low pass. But a bit boated because everything else was all out of whack and very thin. Thank goodness for Lpads and tone control.. It took 200 hours before my tone controls were back to flat, and Lpads at 11-12:00.

4 pairs all the same...  Years on a center speaker, because I don't use surround.. That one really cracked me up.. Any one need a LCR VMPS neo 8 planar center speaker. Just broke in after 13 years NOW... LOL

Some stuff does take a LOT of time.. just sayin'

Relative output of your driver's did not change more than a fraction of a db after the first few hours. The crossover points may have changed a very small amount. The l-pads and tone controls were not doing what you think they were.
All in a speaker changes with use, some faster and some not, mainly moving parts, followed by xover parts, cabling, binding posts.
They should sound good from day one but to reach full potential it takes some time.
Keep listening.


So many views. A confusing mess of heartfelt comments. Who knew it is soo complex. Everything is complex.   quantum physics is complex and so much not well understood. So driver breakin process is quantum physics. So most have no clue what’s going on.

I think making tea is easy. Maybe just a glass of water, no cubes.
Don't let the naysayers and the "wire = wire" crowd here fool you. Break in is real and depending on the speaker and the design, can be pretty substantial. Not only do driver surrounds break in, so do the electronics in the crossover. I have experienced it many times. But some here would have you believe that if they can't hear it, you can't either. All bulls&*t......


Agree totally!

 Mine took a good 200+ hours, the bass was a bit deeper, and hit faster, with a faster recovery time for the next kick drum.
midrange was the biggest sound improvement, guitar, etc was much better after a few hundred hours.

The biggest and most measurable change happens as the big driver’s suspension breaks in. Usually this results in a very small reduction in the resonant frequency, and a change towards the manufacturer’s expected sound.

Some caps change quite a bit in sound quality, though in weird ways. I listened to Mundorf MKP caps breaking in with a pair of Focals, and I swear I had sounds coming from behind my chair until that finished. :) I have no idea why, but I proved it to myself and no one else. :)


i stand by my comments i made earlier that break in is real, and can be substantial in higher res systems

that been said, if you get new speakers and really don’t like the sound, it is unlikely the sound after breaking in will magically please you - usually the impact of break in is slightly more bass richness and speed, smoother treble, more openness in the lower treble and midrange

there will not wholesale changes to the sonic nature of the speaker
+1  If you don't like the speaker the first time you hook it up at home, break-in is not going to magically transform it.  If you do like what the speaker is doing, it's only going to get better--more so--over time.  I don't think you can generalize about tweeters, midranges and woofers--each brand and model is going to be a little different.  The materials science aspect of break-in has already been addressed.
Zu does the break in at the factory, 100-200 hours before shipping out...I did not like the Vandersteen 3 after only a few hours playing (at a friend's shop), thought they were awesome and bought them after they had played about 200 hours...
No one has even attempted to answer the question: What is the science?

The two parts that are easiest to explain are spiders and surrounds. These are typically accordion shaped or pleated, folded, however you want to call it, and so they stretch and bend with speaker cone travel. Whatever the material, almost doesn’t even matter, it is never perfectly manufactured. There are always lots of little regions of stress and tension or compression. Playing music stretches and compresses the material. In some of these restricting areas the bonds break and this reduces stiction and the driver moves more freely.

Think of a crease in a sheet of paper. Fold it back and forth a few times, the crease that was stiff becomes almost like a hinge. Might not be measurable but that freedom of movement allows the driver to respond to big dynamic swings and subtle audio details. Exactly what we hear with break-in.

Break-in of speakers is not a "pie in the sky," but the phenomenon and the time it’ll take for the speaker to settle can vary of lot depending on playback level and the specific drivers and passive cross-over parts used. Alan Shaw of Harbeth will tell you it’s bogus and a phycological effect, and if that’s a universal statement meant to encompass most every speaker, I’d disagree. I don’t know whether Harbeth tests all of their speakers for a duration of time before they leave the factory, but if so I wager the costumer buying their speakers will notice less of a difference with regard to break-in. This may of course apply to other brands as well. Even so, if speakers have been stored up for a while, not least in low-ish temperatures, they’ll take a little time to settle in - despite the fact that they may have been tested for hours prior to leaving the factory/assembly facility. More mechanically rigid, rugged suspension materials like pleated cloth surrounds, typically of higher sensitivity drivers, as well as their spiders are prone to need a beating before loosening up (see the 6moons review of the WLM Diva Monitor with a 10" Eminence coaxial driver).

(more speculative, perhaps)
While the mechanical, moving parts of drivers may account for the biggest change in sound during break-in, there’s also the possible influence of magnetization of the areas surrounding the magnet. For this unwanted magnetization to cease (permanently) requires heat build-up in this voice coil and magnet, in other words that the speakers have been played at fairly loud (though still safe) volumes for a duration of time. Maybe this accounts for why some people feel their speakers suddenly sound better, even after years of use, after a party or other thorough workout they haven’t previously received.

Even though my current speakers have been broken-in (from years of actual pro cinema use), I find they sound better when played at moderate to loud levels for an hour or more (or less, depending again of the playback level) after I turn on my stereo. A well known scenario is what follows having watched a loud action movie for a couple of hours, where they sound their very best.
It really does depend upon the type of speaker. Planers especially benefit from a break-in period. But mostly it's psycho-acoustics in that it takes time for the listener to convince himself that his speaker purchase was money well spent.
Generally when you break something in you make it more relaxed or make the tolerance is greater. That’s what happens in a motor or a T-shirt or your favorite pair of jeans. The tolerances go out the window. In my opinion I would say that they would sound pretty darn close to what you bought that day.Just like anything else that you break in, a motor a T-shirt a pair of jeans etc.
There's a nice article on driver break-in at the GR Research site complete with measurements of various drivers as a function of time.  

Truth always seems to be somewhere in the middle.  It's just a question of where the fulcrum is placed
Alan Shaw of Harbeth will tell you it’s bogus and a phycological effect,

There's a nice article on driver break-in at the GR Research site complete with measurements of various drivers as a function of time. 

I have no reason to question Danny's numbers and I know my colleague has had some discussions with Danny over the years, I think they even defended each other on this topic on a forum once.

It goes back to the ops questions,
"So have these new speakers and been told they need a hundred hours to be broken in, and then sound will improve."

... whoever told him this was out to lunch. They don't magically improve after 100 hours. The major compliance "issues" work themselves out quickly, i.e. the distortion will drop quickly. After that, the driver has predominantly settled in 5-10 hours. After that, it will be subtle changes and more so on the bass. The changes in the other speakers, i.e. crossover points, etc. would be within the tolerance of manufacturing.

w.r.t capacitor break-in, I would challenge anyone to show any measurements of a film capacitor that shows parameter changing greater than the part tolerance ran at the typical volts/current in a speaker.  Don't say "well we can't measure" ... We can't interpret how humans will respond to the measurement, that does not mean we cannot measure changes.  Some capacitors are not well made and susceptible to absorbing moisture, and could change with humidity / temperature. Well most will change with temperature to some degree any way.

Like I said, and a LOT of folks using fancy caps, they make noises that are hard to explain. Measure? Who would want to.. I’ve heard teflons break in a couple of times. After that, I put mine face to face, covered them with heavy moving blankets in the shop and let them run 4-5 days at 60 70 DB. They use to run tone generators on speakers for a week before shows.. It’s usually the last days of the shows the systems sound the best.. It has more to do with settling and breaking in.

Danny at GR is a master of taking advantage of all that.. Big curtain guy too..

I loved the VMPS CES show stoppers.. Danny never had good word for VMPS, other than. I like to help Brians customers.. Nothing has changed.. Still fixing 100 year old companies XO, saying "I fixed them"
Hell I could fix anybody STUFF after the fact.. "BURNED IN" guy.. I quit listening right after that.. They break in, good Lord. I bet he works on his motor, and changes the oil. ENGINE. Words count... 

He was quit the SA in his early years with other folks speakers.. Still is taking on JBL and a few others.. LOL Yea... I own his servos, pretty good stuff. BUT I sold his redesigned 123s, What a pile of crap, they were.. OB piles of junk...Could never get them right.. Looks, They were nice looking... Good for parts...

My RM40, 30, RM2 and Elixirs, whip the pants off of them. Actually a lot of his earlier stuff.. His newer designs Danny is hard to beat for the money.. BUT it can be... Nothing I’ve HEARD on these forums though..

But I’ve never hear a Magico, probably never will..Wilson same way, no interest. Watt Puppies I’ve heard. Give it to me, maybe. Pay for them NEVER... Danny he insulted my friend Brian C to many times... AFTER he was dead.
Yea, about that guy.. LOL He may live in Texas, but he ain't no Texan..

In some speakers and electronics the difference in break in can be dramatic but in others there is only a slight change my hope is that the drivers are real good and the former will occur for you but what i can say is that letting your system warm up with background music for an hour or two will really help before you seriously listen every time you play your system.
I doubt there is very much to it. It is mostly your ears getting used to the new speaker. Yes, there may be some break in happening like anything else, but no where near as long as some suggest.
Are you using ported speakers? Is that how the spiders enter the enclosure? My cabinets are sealed enclosure.  HVAC
Relative output of your driver's did not change more than a fraction of a db after the first few hours. The crossover points may have changed a very small amount.
Back in the day, we broke in studio woofers with a Crown DC-300 input pad plugged into the wall. Played 60Hz for at least 24 hours before swapping. Never measured for any level difference, but sonically, un-buzzed woofers sounded flat and lifeless. Old woofers were sent back for reconing. Mid/Tweet drivers could be reconed on site. Techs used to hang shredded diaphragms on the wall marked with the band / musician who blew them.

Note that the above speakers were abused and suffered mechanical failure. 

To the long break-in crowd:
Do you log listening room parameters Temperature, Pressure, Humidity, Line Voltage? see  ieLogical WinterBlues
How accurate is your level control? [Have you ever verified it?]
Have you verified the amp is operating at EXACTLY the same BIAS point?

My 35 year old speakers break-in CONTINOUSLY due to the above. The CBLF is infallible and contributes not...
Psycho acoustics? After MC comments, this makes no sense.

Everything makes sense. You just have to look at it logically. A lot of people are psycho. Unable to distinguish fantasy from reality. Some of them hear sounds, don't know what they are. They are psycho-acoustic.
Years ago when I received my Shahinian Diapasons I remember them taking a long time for the sound to settle in. For the past year I have a pair of Bache Audio Tribeca speakers and they sounded great right from the start. If there was any change with these speakers it is unnoticeable. 
My experience tells me that the crossover plays the largest role with speaker break in. The Diapasons have a very complex crossover, while the Tribeca's use a cap on the tweeter and a coil on the woofers. The wide band is directly connected to the amp.
How does one tell for sure if the speaker's sound is really changing over time, and it's not due to things like variations in hearing over time, air temperature or pressure, mood, acclimatization to the new sound, etc.?

A bench test can be performed with the driver playing a sine wave frequency at or near speaker free-air resonance (fs). Keep driving the speaker for a known period of time. Measure the fs at various periods of time. If fs changes due to speaker suspension break-in or loosening up, the fs should decrease. Manufacturers should already know whether break-in is needed.
How does one tell if anything is really changing over time? If you rely on some kind of test that is dishonest. Why? Because then the question is how can you rely on the test? How can you be sure something there hasn't changed as well? But really, bottom line, who is it that is doing all this relying, anyway? There is no escape here: it is YOU! 

Learn to listen. If you can't hear it, what do you care that others can? If you can hear it, what do you care that others can't?

I don't really care that some people can't hear. My only concern is putting the fact out there that it is possible. How far they go with this knowledge is their business. Just wish people wouldn't confuse their inability with mine, or anyone else's. 

I know, don't hold my breath....