# Sticky  Driver Break in - Fact or Fiction?



## phaseshift

I have notice a debate about speaker break in on this and other forums. As someone that has been around this for many years, particularly at the factory level, I would like to offer my observations and some facts to clear the air. 



> I think where the myth of break-in occurs is at a factory production level.
> 
> Most speaker drivers are tested to verify their T-S parameters and frequency response before assembly. This requires some testing at the factory. Plus, once a speaker is built, there is usually a test period to verify the crossover and drivers are all working as planned. Granted, this is not a full 40 hour burn in, but the drivers have at least seen some use before going to the consumer.


 It is true that the drivers do see some testing prior to final pack out, but it is not really accurate to say that this breaks them in. 

Generally, a driver will get a sweep test a couple of times during it’s life and nowadays, a response check as well. Sweep voltage depends on the customer or manufacturer’s preference, but you would find a lot of drivers swept at about 4 to 5 volts from their target resonance to a bit higher up to around 5K. Tweeters a little different, but again, a reasonable range; mainly looking for loose particles or a RVC condition (voice coil rub). This sweep will typically be over in 3 or 4 seconds max- that is it. You would again have this sweep test as the driver is installed into the system and again at the system level. The amount of change you see in the suspension is minimal- there are just not enough cycles or at a high enough power level to really impact the stiffness of the damper or the compliance of the surround. 

Testing – for instance a MLS or other stimulus – response test is also at a very low level and is completed in a few seconds- again, you just do not have the power or duration there to impact the compliance of the driver. When it comes to testing tweeters, you will often see differences as well- often due to dispersion of the ferrofluid in the gap. I have done a very extensive study on this as a QA – manufacturing project for a high end and very well known OEM who we supply automation equipment to and the ferrofluid balance was the biggest factor for changes in the tweeter over the first few hours of it’s life. (FYI- When I proposed this concept before the study was done- I even thought it to be an absurd notion but the facts were that it was actually the thing that caused a lot of problems at the manufacturing level.) For drivers that do actually get a parameter test run on them before shipment (very uncommon except among more expensive subwoofer drivers), the signal level is very small and the timeframe is very short. There are a couple of platforms out there that will do rapid T/S parameter testing using a fixed Mmd based calculation. MLSSA, Clio QC and I believe Sound Check will do that sort of testing. You can use a Klippel to do high level testing, but this takes quite a while and is certainly not a production level test for any driver that I know of. 

For those that do not believe in the break in time for a driver, here is a way to prove it to yourself once and for all…

Break in is very real and anyone with basic testing skills and equipment can verify that it does happen. How? First of all, you can look at the driver Fo – right out of the box. Measure this about 10 times and then average the number. Now put a signal through it at moderate levels for about an hour. Let the speaker cool down for one hour. Measure the Fo again, get the average and compare. Want more proof? Go for the full Monte T/S parameter testing using a similar routine… Multiple tests, average the numbers and then run a signal on the driver for an hour or so. Cool down time, re-test, re-average and compare. Still not convinced? Set up the driver in an anechoic environment, lather, rinse, repeat as before and observe the differences in the response, particularly near resonance. 

What breaks in?? Mostly the damper, but to some degree, the surround as well. In general, the surround has a far smaller impact on the mechanical model of the speaker, but it is there a little bit. Mostly look at the damper and how much it changes over the first few hundred cycles at or near Xmech and resonance. There may be other factors as well, but they are going to be minor in comparison to the damper compliance change and the overall changes in the mechanical model of the speaker as related to that. Obviously, in a design that does not have a damper, the changes you observe will be different. Tweeters and other single suspension devices typically operate at very low excursion, higher frequencies where the mass and shape are the bigger factors. 

Electrical break in- I have also looked at electrical break in of drivers and I will say that it ranged from minimal to a non-issue on a typical driver. There are slight changes in the coil after heating and the magnets can loose some of their zip if overheated; especially cheap-o and low Y factor stuff (it is my experience that is true anyhow…). This is mainly a factor in the cheaper stuff that most of you would not have any desire to fool with, but is all over the word, particularly in LCD / Plasma TV sets and other consumer goods where the heat generated by the driver is not the big issue- the device that the driver is located in is the overriding factor. You would also see differences in the planar drivers such as the Neo 3, but I would expect them to be absolutely minimal at the electrical level unless the driver was abused or overheated. 

Others here may have done studies related to the electrical changes in coil drive devices (drivers and tweeters) and they may have different experiences or comments. Particularly in a case like a large, high power sub with a multi-layer coil and enough Bl to bend space a little bit. I have not had the opportunity to delve into that sort of driver on a study like this, but it would be interesting to hear from some that have. Manville from JL is probably the most likely candidate that I know of on here- they (JL) have a lot of really heavy duty drivers and I believe that JL actually puts a lot of brain power into their products. It would be interesting to hear from them on this topic.

_Edited note - Damper = Spider_


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## Geoff St. Germain

Yeah, I've seen before and after measurements of LF drivers showing changes in Fs, Cms and Vas. I've seen measurements for the TC-3000 here and I saw measurements for a Peerless woofer on another site.

The only thing that gets me is breaking in cables.


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## thxgoon

Geoff St. Germain said:


> The only thing that gets me is breaking in cables.


Only if they're properly isolated from the floor and made of pure silver whose molecules have all been oriented in the same direction lol!!:bigsmile:

Great read phaseshift. Thanks!


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## Sonnie

Thanks for the detailed explanation Gui... I've made this a sticky here and copied it to the Home Audio Speakers forum as well.


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## drf

As someone who has always believed in speaker break in only because every moving object wears at some level thus changing its characteristics not because of testing and various study results. I have often wondered just how much impact the break-in has on sonics of a speaker system. Is it really audiable? I haven't had the pleasure of owning a set of speakers from new, just drivers for my own homebuilt projects, yet haven't heard anything to write home about after a few hours/days of use.

Now I know my ears aren't that bad, I manage to score all the difficult audio engineering jobs like multi sophited churches with bucket loads of big brick pillars, or engineering the local charity concert in a stage theatre from a room 99% detached from the auditorium :wits-end:. although I am no professional, I never seem to detect enough of change in sonics to warrant the worry about it.

What are other peoples thoughts on the perceptability of this?


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## phaseshift

drf said:


> As someone who has always believed in speaker break in only because every moving object wears at some level thus changing its characteristics not because of testing and various study results. I have often wondered just how much impact the break-in has on sonics of a speaker system. Is it really audiable? I haven't had the pleasure of owning a set of speakers from new, just drivers for my own homebuilt projects, yet haven't heard anything to write home about after a few hours/days of use.
> 
> Now I know my ears aren't that bad, I manage to score all the difficult audio engineering jobs like multi sophited churches with bucket loads of big brick pillars, or engineering the local charity concert in a stage theatre from a room 99% detached from the auditorium :wits-end:. although I am no professional, I never seem to detect enough of change in sonics to warrant the worry about it.
> 
> What are other peoples thoughts on the perceptability of this?


The point I am getting at here is not to say what a person can or can not hear… That is up to the individual listener. My point is that there are mechanical changes in a speaker that can be measured and that do have some impact on the performance, including the response. 

I would say that from a listening only point of view, it would likely be a lot tougher to distinguish differences in a speaker system in a PA application as opposed to a listening room or other hi-fi application. In the typical PA application, you have a lot of reflection and acoustic issues from the room + multiple source points, multiple path lengths and in a lot of cases, you are not able to use common speaker sets to fill the venue. My experience tells me that distinguishing a difference in that sort of environment would be just about impossible unless you were starting from scratch with all new gear and you have a pretty “clean” environment (less reflections than your typical auditorium).

From a DIY point of view, I would say that this is the best opportunity to see the changes since you can measure, poke and prod the speakers and see the changes before you put them into the system. Just as importantly, you can see how closely the drivers match as a new set and how much they change and finally, how close they are after they have been in use for a few days. 

As a side note- 
My wife saw me typing on this topic and said “why don’t you mention how simply pressing on a (new) driver far enough to get near bottoming will make the Fo drop a bit or how massaging the tweeter dome will sometimes fix the problems with the response?”. Well, she is right; the simple act of just running a driver through it’s suspension limits one or two times will give you changes on the mechanical side of the equation.


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## tonyvdb

I just spent over an hour talking to a friend who just happens to work at one of my favorite high end audio stores here. National Audio and befor that Premier Audio (he has worked these stores for over 15 years so he knows his stuff). He said without a doubt there is a break in period for speakers. Some are very noticeable and others not. 
This is even more evident in subs because of the excursion that the speaker has to do. The speaker surrounds soften up and the coil will change as it heats up and the copper expands and fits into place. This will take weeks of use sometimes before all has settled into place.


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## Kal Rubinson

tonyvdb said:


> I just spent over an hour talking to a friend who just happens to work at one of my favorite high end audio stores here. National Audio and Premier Audio(he has worked these stores for over 15 years so he knows his stuff). He said without a doubt there is a break in period for speakers. Some are very noticeable and others not.


Yet another anecdotal report. Old news.


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## drf

Thanks for the response, but I am not questioning the fact that there is a break-in in drivers. As I said before simply the fact that it is a mechanical device suggests there has to be some sort of change in its structural integrity over use. The reference to P.A and re-enforcement drivers was merely a clarification of my hearing abilities*, I did not mean for it to sound like I was referencing p.a gear as a means of judging whether or not break in occurs.

I was/am, however, interested to know how many people believe they have perceived an audiable change in drivers after a break-in has occured? 

I think your wife is right too, although I would still question how perceivable the change is after a cone was massaged or brovcken in in such a manner.

*on a side note; I have noticed that even the cheapest hi-fi drivers/enclosures are leaps and bounds above top end Pro-audio gear as far as clarity and depth are concerened.


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## Mike P.

Kal Rubinson said:


> Yet another anecdotal report. Old news.


Yes it is, for those who are familiar with the subject. But it's "new" news for someone who is just learning.


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## Kal Rubinson

Mike P. said:


> Yes it is, for those who are familiar with the subject. But it's "new" news for someone who is just learning.


Unfortunately for them. There's little to learn from such reports but they do create a bias.


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## Guest

Fact: it's a mechanical system.

To the OP, solid post. Sometimes it is indeed best to steer clear of an audibility argument because you know where that goes.


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## loupy31

Guitar amp speakers, you will notice a "........HUGE......." diference in tone quality as the speaker is broken in


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## 1Michael

To answer the original post. I have no way to measure such things but having built 3 sets of main speakers and half a dozen subs, in every case the speakers when finished all sounded like trash to the point that I wanted to take a sledge hammer to them. After about 100 hours they become listenable and after a couple hundered hours they all start to sound decent. Now some uninformed individuals may tell you it is because I have "gotten accustomed to them" but that is nonsense. The sound changes and my wife has heard it also. There is a break in for drivers. Now subs dont seem to sound much different do to the lower freq's but I still run my 0-100Hz CD on those as well.


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## Anthony

I wish I had saved the plots, but I did not:

I ran an impedance test of a Dayton RS 8" driver new out of the box.
I ran one three weeks later after a lot of testing and breaking in.

Completely different animals. The impedance peak shifted down about a half octave and the high end rise tapered off considerably. 

To me it's that simple, if the measurement showed a difference (and a big one at that), then break-in is important. It did and the speaker I built with it sounds much better after 100 hours now than it did after first assembly.


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## drf

How come noone hears a change in sound quality for the worse after a driver has been "broken in"?

it just seems a little confusing to me that "ALL" speakers sound better after breakin, yet none sound worse.


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## Geoff St. Germain

drf said:


> How come noone hears a change in sound quality for the worse after a driver has been "broken in"?
> 
> it just seems a little confusing to me that "ALL" speakers sound better after breakin, yet none sound worse.


I would think that in some cases the driver may sound worse, but one thing to consider is that if the driver is being crossed over, such as a woofer or mid in a two or three way speaker, the crossover is likely designed for the "broken-in" parameters. In this case, I would expect that for a well designed crossover, the driver will sound best when it's parameters are closest to the parameters for which the crossover was designed.

Also, if the change in sound is small, then people may either not be able to detect it, and simply feel it sounds better because they are becoming used to the sound, or they may not be able to perceive the change as being either good or bad and simply say it is good. I thought my WMTW center sounded great as soon as I put it together. It still sounds great and I can't say that I've noticed any change in the sound of the speaker even though the drivers' parameters may have changed slightly.

Of course, I could be wrong, these are just my thoughts on the issue.


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## tonyvdb

drf said:


> How come noone hears a change in sound quality for the worse after a driver has been "broken in"?


This is simply because manufacturers break in their test speakers before making any final adjustments to the tuning of the cabinet or crossovers and then sell to the public that design knowing that the speaker will sound the way they want it to after the so called break in period.


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## Anthony

Oh, I was simply referring to raw drivers for DIY projects. With manuf. speakers, many times they are partially broken in to test for bad drivers, make sure the crossover is performing correctly, that sound actually comes out 

For raw drivers, with few exceptions (from what I've read and experienced), the drivers are straight off the manufacturing line. Parts Express even recommends you run a break-in / test right away to make sure the drivers are in good shape so they can send you replacements if you got a bad one (I guess some people shelve them for a while and then the return/warranty period has expired).


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## Guest

*Fiction...*

I wouldn't think the low frequency drivers would "break-in" very quickly once installed in a damped enclosure.
Mine hardly move at all with normal program material.

Also, the suspensions are just that; they simply suspend the cones and domes and really should not be a significant part of the overall resistive load.
In any event, countering or altering the electromotive forces from the motors would be analogous to a kitten trying to impede the movement of an elephant.
If anything happens to "loosen" the compliance of the suspensions, I would think that those effects would degrade sound quality, not improve it. Similar to a new shock absorber becoming more compliant over time, resulting in reduced damping of vertical shocks to the car suspension.

Any effects that cold storage and shipping has on driver compliance probably constitutes the bulk of the effects of break-in, and should clear up, with or without music being played through the speakers, once the air within the speaker cabinets warms up to the temperature of the listening environment.


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## Kal Rubinson

DevilDriver said:


> Fact: it's a mechanical system.
> 
> To the OP, solid post. Sometimes it is indeed best to steer clear of an audibility argument because you know where that goes.


True. Unfortunately, audibility is the only pertinent issue.


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## Guest

"Audibility" is often an act of sheer determination as it applies to subtle variations in the texture of a soundwave.
Just knowing that there might be changes in a soundwave due to a preconception is enough impetus for some listeners to actually hear and be pleased (or bothered by) those changes, whether they are audibly significant or not.

It's probably safe to ignore small variations in the sound caused by cables, break-in, sunspots etc...
These effects are so minor that they are literally *swamped* by the larger distortions inherent to the speakers and room.
Toeing-in the speakers 5º is probably going to yield more significant audible changes to the sound than break-in will.


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## Kal Rubinson

snickelfritz said:


> "Audibility" is often an act of sheer determination as it applies to subtle variations in the texture of a soundwave.
> Just knowing that there might be changes in a soundwave due to a preconception is enough impetus for some listeners to actually hear and be pleased (or bothered by) those changes, whether they are audibly significant or not.
> 
> It's probably safe to ignore small variations in the sound caused by cables, break-in, sunspots etc...
> These effects are so minor that they are literally *swamped* by the larger distortions inherent to the speakers and room.
> Toeing-in the speakers 5º is probably going to yield more significant audible changes to the sound than break-in will.


Bravo! :clap:

Kal


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## ISLAND1000

Any speaker when it is used will then go through a break-in period. There doesn't seem to be a way to avoid a break-in period. I can accept that. It's like that first two weeks after you get married . . . . .


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## Scuba Diver

I wonder if this is why so many people return speakers. I am very new to all of this. I am learning as I go. So thank you for this post.


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## toecheese

drf said:


> How come noone hears a change in sound quality for the worse after a driver has been "broken in"?
> 
> it just seems a little confusing to me that "ALL" speakers sound better after breakin, yet none sound worse.


Heh, a good question and one that is pretty simple to answer. When your speaker is completely 'broken in', you've worn out the suspension, the coil starts rubbing, etc. Mechanical devices break down, and as we say in NC, it'll just be 'broke'. 

*That's* when it sounds worse ;-)

I think the requirement for break-in, even for DIY, is not as big a deal. Maybe in the past because of more primitive manufacturing...


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## Guest

Scuba Diver said:


> I wonder if this is why so many people return speakers. I am very new to all of this. I am learning as I go. So thank you for this post.


The reasons people return speakers has more to do with the environment than the speakers.
1) They don't take a CD they are familiar with so have to listen to the store tracks only,
2) The room the speakers end up in are quite different than the showroom,
3) They don't take the time to balance levels and position the speakers for best result.

As was mentioned earlier, all these things probably account for mor perceptual differences that any changes due to breakin.


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## Anthony

Yeah, the more I learn about speaker building, the more I realize that it is impossible to design one speaker that sounds great in every room.

Even just the distance from the wall can influence the crossover design. On wall speakers have a different baffle step compensation circuit than those who are away from the wall. So try picking one design and having two people take it home -- one mounts it on the wall the other puts it on stands. Two completely different experiences.

that's why I like learning about crossover design. As of now, I'm designing for my room. If I go to a bigger room and notice new problems, or have to turn a design into an in-wall, I can simply redesign the crossover (or baffle) to compensate.

I do stand by my break-in statements, though. The giant 15" woofers I am using for my dipole bass measured very different out of the box versus 20 hours of listening. I have one more to break in. I will do the measurements and post results (so far I haven't saved them, since it was just for subwoofers -- i.e. no passive crossover to design). I doubt it's a big difference, but if you designed a crossover based on one expected impedance plot and it changes, well then you end up with a different response.


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## drf

Anthony said:


> Yeah, the more I learn about speaker building, the more I realize that it is impossible to design one speaker that sounds great in every room.
> 
> Even just the distance from the wall can influence the crossover design. On wall speakers have a different baffle step compensation circuit than those who are away from the wall. So try picking one design and having two people take it home -- one mounts it on the wall the other puts it on stands. Two completely different experiences.
> 
> that's why I like learning about crossover design. As of now, I'm designing for my room. If I go to a bigger room and notice new problems, or have to turn a design into an in-wall, I can simply redesign the crossover (or baffle) to compensate.
> 
> I do stand by my break-in statements, though. The giant 15" woofers I am using for my dipole bass measured very different out of the box versus 20 hours of listening. I have one more to break in. I will do the measurements and post results (so far I haven't saved them, since it was just for subwoofers -- i.e. no passive crossover to design). I doubt it's a big difference, but if you designed a crossover based on one expected impedance plot and it changes, well then you end up with a different response.


Absolutely, this is why all my designs use active x-overs. You can simply dial in a new setting for environment changes. 
I honestly don't think anyone is questioning if driver break-in occurs, however there seems to be plenty of question as to whether this is audiable or not. I guess just how audible break-in is depends on many factors, And I would bet a big one of them is driver size and sensitivity.


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## phaseshift

Something worth mentioning here is that most of the design folks I know do their system work using drivers that have been broken in from a mechanical point of view at least. I typically will run the tweeters or midrange drivers at about half power using the EIA 426-B test signal (something like pink noise) and woofers using shaped tone bursts for an hour with the bursts at or about the resonance of the driver and the amplitude high enough to get the driver to X-mech; not X-max, I want the driver going as far as it will travel- including out of the gap so that the suspension is fully worked. 

I probably should have mentioned that in my original post.


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## Guest

I have a speaker tester and I've noticed that parameters change after the speaker has been used. I noticed one person said it is a question of what you can hear or measure? For me because I design speakers I have been able to test many of the same drivers side by side! I know that I can hear an audible difference after about 20 hours. The drivers tend to even out and loose a bit of that "hiss" sound on "s's" and "t's". I know of a few speaker manufactures’ that only test their raw drivers after they have been brought to "normal" operating conditions. It is then that they administer the tests that you will see on the data sheets. 

As for the person above here who has posted a question. Our ears can trick us much like a magician can trick our eyes. It has been a while but if I remember correctly. With psychoacoustics if a person hears a set of speakers in a show room the last ones they hear will always sound the best. Finally, what ever model is being "pushed to sell" is turned up the loudest. This will make them sound the best in the show room. 

However, no matter how "good" they sounds in the show room your room is much different. I think a combo of psychoacoustics and the fact that a certain type of speaker and placement will drastically affect the sound quality in your room probably play a bigger roll in the if someone takes their new speakers back to the store. If people are truly buying high end speakers most high end manufacturers have already played their speakers to what they call the "break in" point. With my business I play every set of speaker for at least 30 hours before I’m happy with them. Besides it gives me the time I need to perfect them before I ship them.

K :1eye:


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## Bill Fitzmaurice

Driver break in is real, especially with woofers. It takes a good 24 to 72 hours of use for the suspension and spider to loosen up and for the driver fs to come down to spec. OTOH I've seen it claimed by some speaker (not driver) manufacturers that up to 400 hours of use is required for full break in. What really happens in that instance is that you get used to how they sound and no longer notice that they aren't very good.


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## thewire

I disagree. My skeptcism of the way my HT sound only gets more critical, and not the opposite. That does make since they would recommend such however because by 400 hours they may have forgotten what they wanted it to sound like to begin with.


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## andru

I think it is really possible to hear the difference in a "brocken in" driver, especially a bass or say a 10" driver.
As a guitarist with a bunch of old tube amps I am always looking for a way to get a vintage (used) sound from a new speaker or driver.
This topic brings to mind my method of aging a speaker... for better or worse, (if it breaks, get another one until you get it right...)
well anyway...
Recently I wanted get a vintage sound (more bass/low mids from a pair of new 10" speakers) when I put the two new celestion 10" speakers in an open backed cabinet, there was just no gut wrenching low end, just a sort of honky hi mid... 
so the old musicians trick/methodology goes something like this...

Take the speakers out of the box, sit them on their backs and pump a reasonably low tone through them. Something that makes the speaker really work hard, but don't kill it....by over doing it. (if it's a 10" don't go too low with the sine wave...)

Using some kind of protective gloves for hands and skin and the wife's new carpet.... paint some acetone around the rims, evenly... leave them to cook (play for a while... how long is up to you.) 
But you may well notice a change in the timbre/quality of the tone after a while....
test them again to see if the bass end has improved/changed. If not try again ...maybe longer... more acetone (but again... don't over do it.)
It worked for me, and is how I always used to break in the new Jensen 10" to get the real blues warmth...
Now how this will translate to HiFi is anyone's guess, but it is fun, however my cat, wife and children were not impressed. 
It could be something you might try on a cheap sub speaker or two... just to get the hang of it....
and to see if you can tell the difference or even improve the beastie.
Thanks for listening.
Andru


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## Bill Fitzmaurice

andru said:


> Take the speakers out of the box, sit them on their backs and pump a reasonably low tone through them. Something that makes the speaker really work hard, but don't kill it....by over doing it. (if it's a 10" don't go too low with the sine wave...)


That should be standard proceedure with all woofers. I break mine in with a 20-25 Hz tone at 8volts for 24 hours. Then I measure the fs to be sure it's at spec before mounting the driver. With mids and tweeters break in prior to mounting isn't as critical. 
Typically a woofer fs will run at least 10% higher than spec prior to break-in.


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## looneybomber

Bill Fitzmaurice said:


> That should be standard proceedure with all woofers. I break mine in with a 20-25 Hz tone at 8volts for 24 hours.


I used to do something simliar (used a sweep from 15-25hz or so), but now I try a different method. High power, short duration with this song. It has a lot of 20-30hz energy.
YouTube - SDX-15 video 2
It gives a good stretch with a short enough duty cycle to keep heat from being an issue.

This method is a different story though.
YouTube - Fs3 Sub Speaker best Excursion Prototypes


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## andru

I guess so, but a lot of people probably never remove the speaker from the box/cabinet... if it's pre installed...
some small thing called warranty I guess. But.. well, I am a tinkerer... some are... and some not.
I call it freedom to experiment... but I'm off track... sorry.

Andru


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## BrianAbington

I had a pair of vifa 7" midbass woofers I put in the doors of my jeep. I was really upset with the way they sounded at first. They had no depth to them at all and didn't play very loud.

So I figured I would give them some break in time.
I would spend hours in the parking lot of our apartment just listening to music in my jeep.

I noticed that after about 35 hours...(yes I kept track) they sounded much cleaner...and had really nice definition, and played pretty low. 

I don't know the math behind the electronic side of this...but from an audible standpoint I think that yes it does make a huge difference.

My dad used to work at a ultra highend audio store and they did a break in process on all the speakers on the floor were they played pink noise through them for 48 hours on a test bench.


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## Bill Fitzmaurice

SQCherokee said:


> I don't know the math behind the electronic side of this...but from an audible standpoint I think that yes it does make a huge difference.
> .


The math is unimportant. The result is major, about the same as how comfortable a pair of leather shoes are after a few months of wearing them compared to when they were new, and for exactly the same reason.


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## Kevin Haskins

I'll stay away from the subjective side of this debate but the following happens with suspension components.

The Cms will rise after some initial break-in period (Cms is distance of movement/unit of force so larger means that the suspension gets softer). How much, depends upon the suspension of the driver and the construction of the spider & surround. On subwoofers, you can see about a 10% change in Cms with break-in. 

One thing to note, the suspension of a driver is the loosest spec'd parameter. Spider Cms is typically +/- 10-20% so there is a variation in normal production runs. The good thing is it doesn't matter much. If you change Cms and remodel the driver there just are not large changes in the final response of the system so difference due to production tolerance or break-in, are not likely to be audible.

Another thing to consider is that the spider will actually stiffen after sitting. It goes through another micro break-in period during every use. There is also a static coefficient of friction, that makes the initial movement of the spider more difficult than dynamic operation. And of course, all suspensions change with stroke so you get a higher Cms as the cone leaves center. Good progressive ones give you a good range without large changes in Cms. 

Tempeture is also a significant contributor. I've taken a halogen light out and shined it on some drivers to loosen them up for measurements in my cold warehouse. It easily can make 10-15% differences. 

All of these things are very easy to measure (except maybe the dynamic vs. static) so there is NO controversy about these types of changes. The significance of them are often greatly exaggerated but their actual occurance is beyond question.

The claims of electrical break-in and it's audibility is another topic. Suffice it to say that there is no credible research showing any correlation with electrical break-in. That is, nobody has proven any correlation between a wire that has had a signal running through it for a given period of time and one that hasn't. There doesn't seem to be any credible research showing that cones break-in after a given period of use either. By credible, I mean something that is backed by research with peer review. There may be some self appointed gurus who can show you a waterfall with changes but there isn't any studies that show any meaningful correlation with audibility. Suffice it to say that the small changes are of a magnitude to be WAY below what we typically consider audible. 

I'd say the most likely way to describe people's experience with break-in is due to psyco-acoustic mechanisms rather than physical ones. In other words, it is mostly between your ears rather than in the system. That may not be a comfortable thought, because I've heard differences after break-in also, but given the information we have it is the most credible explanation. 

Kevin Haskins
Exodus Audio
www.diycable.com


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## Ricci

That's a great post Kevin. I recently read a thread where a guy was apparently having his vc's break in. He said the dcr dropped substantially. I've never heard that one before and I'm not sure what to make of it. I definitly don't believe that is actually what happened. I just don't see how it could be possible at all.


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## Kevin Haskins

Nahh.... it will change with temp. He may have measured them directly after running them and got a high DCR and then did a measurement later, after break-in, and the taken the DCR after the coil had cooled. That would show the change you are describing. 

The DCR is set by the copper or aluminum length/diameter and obviously that is a fixed parameter. The impedance sweep can be changed by acoustical loading and break-in, enclosure shape/size & obstructions but you don't see any difference in the DCR.

Kevin Haskins
Exodus Audio
www.diycable.com


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## Bill Fitzmaurice

Kevin Haskins said:


> There doesn't seem to be any credible research showing that cones break-in after a given period of use either.


They don't, but in the case of paper pulp cones their mass, and therefore Mms, Fs, Qes, Qms and a half dozen other parameters, is affected by the humidity in the air. If you think your subs seem to go lower in the summer, when average humidity is higher than in winter, they probably do.


> I recently read a thread where a guy was apparently having his vc's break in. He said the dcr dropped substantially


DCR goes down when coils are cold. That's why superconductors are supercooled. The increasing DCR of a coil when heated is the source of thermal power compression.


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## Kevin Haskins

I live in the Pacific Northwest, my subs go lower year round. 

Kevin Haskins
Exouds Audio
www.diycable.com


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## ISLAND1000

Then as global warming continues the best driver performance will be had at the "poles" both north and south it seems . . . . . except for "hysteresis" and the effects of the Van Allen radiation belts.


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## kryptonitewhite

YouTube - Maelstrom-X

I have been breaking in my subs for years, and have frequently noted something that happens in this vid....

When I start, i bring the driver to it's point of mechanical discomfort... always freeair of course. Once i reach that level, I do not back off only a notch!!! I back off several, because as you clearly hear in this video, the driver breaks in and achieves a higher excursion with the same level of input. I break mine in over several hours in a room that I will be in for the whole duration, and sometimes I have to re-back down the input level multiple times as it begins to over excurt slightly as the compliance decreases.

EDIT

I re-watched the vid, and noted there could be a few misunderstandings, then I scanned through this thread further (I didnt read the whole thing) and noticed there are other vids 

Anyway, I noted:

up until 17 seconds, it is playing at low level, then he begins adding input...and it needs to be noted that the repeating track is increasing in frequency, generally excursion should go down as it gets higher. Would have made for a better example if it were a constant tone.

at 24 seconds the first hint is easily heard of nearing limits, then continues to increase... while increasing input as well?

35 seconds is the clear point of overexcursion

at 46 you hear it again, and he notes it, and backs off... but i believe he leaves it?

at 57 it overexcurts again... was it at the same input level since after he backs off at 46 seconds??


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## Guest

as a rock guitarist, i can assure you you DO need to break in speaker drivers, i've blown thousands of speakers up over the last 40 years or so...

if you break them in they seem to last longer and take more abuse...granted, i'm dealing with a situation where i'm LOOKING for distortion ;P

we used to take speaker cabs, hook up an amp and feed a guitar back overnite at a low level...
those abused speakers seemed to function much better.

so i would suspect breaking in a driver, much like anything else, would be wise.
peace


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## Ricci

That Mal X is not too happy at a couple of spots in that video. Sounds like either spider slap or suspension bottoming. Too bad the video is a low resolution it's hard to actually see what's going on with the driver or what the excursion levels are (looks pretty high). The Tempest X never exhibits a noise that harsh in it's video. Maybe it overloads in a bit nicer way. 

IMOP the best way to break in any driver is to just use it the way it is destined to be used.


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## kryptonitewhite

can you even bottom out those 18" 06' XXX's? :bigsmile: :yay:
3000 watts 30Hz on up, disgusting :hide: er scary?


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## Ricci

I was told by the senior RE tech that the suspension is fully stretched at about 63.5mm one way. The vc's would hard bottom somewhere past this point but something on the suspension would have to break first. The suspension starts to tighten up a lot once you get to the ends of it's travel. It would probably take in excess of 1000watts of <10hz material free-air to physically damage the driver.


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## johngalt47

I just built a pair of speakers and the bass improved quite a bit after breaking in. I used SB Acoustics 7" drivers.


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## phaseshift

*Re: Fiction...*



snickelfritz said:


> I wouldn't think the low frequency drivers would "break-in" very quickly once installed in a damped enclosure.
> Mine hardly move at all with normal program material.
> 
> Also, the suspensions are just that; they simply suspend the cones and domes and really should not be a significant part of the overall resistive load.
> In any event, countering or altering the electromotive forces from the motors would be analogous to a kitten trying to impede the movement of an elephant.
> If anything happens to "loosen" the compliance of the suspensions, I would think that those effects would degrade sound quality, not improve it. Similar to a new shock absorber becoming more compliant over time, resulting in reduced damping of vertical shocks to the car suspension.
> 
> Any effects that cold storage and shipping has on driver compliance probably constitutes the bulk of the effects of break-in, and should clear up, with or without music being played through the speakers, once the air within the speaker cabinets warms up to the temperature of the listening environment.


That is out there where the busses do not run.

I have been away from the forum for quite some time, have a bit more free time nowadays to check in.


----------



## Yad

*Re: Fiction...*



> I wouldn't think the low frequency drivers would "break-in" very quickly once installed in a damped enclosure.
> Mine hardly move at all with normal program material.


The same as "Break-out" while you don't use your speaker for a long time


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## Yad

the Thiel-Small parameters are changes a little in both "break-in & break-out" periods.


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## Yad

My experience tells me, that the best way to break up LF and MF drivers - to do that without any enclosure. 

Useful to load them by 2 or 3 sine signals mixed togeter. All freq. should be not multiple. 
One of the freq. is better to be the same as resonance of the driver in free air. 
example: 32, 50 and 20 Hz. 

Such complex signal allows you to have max. diffusor's displacement (better is close to peak-to-peak) with the minimum of voice coil's heating. (The very small power is needed). 

It will be enough of the breaking -up time about 4 or 7 hours.


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## Yad

Once, I treated one very old driver at the same signal. That's fun, but after that, it's Qts fells from more than 2 to 0.7 !!! :R


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## gsmollin

Vance Dickason's explanation is that while the speaker's suspension changes during break-in, parametric shifts that would affect a speaker design are rather small. He recommends a break-in period only to be sure the speaker is not defective. 

My take on this subject is this: If you are designing a new, say DIY, custom speaker system, and you are relying on the exact characteristics of the speakers to tune the enclosures to the exact design you want, then you will be breaking-in the speakers so that the T-S parameters you need have settled to their final values.

If you are designing a speaker system for mass market sale, then you will design the enclosure for the specified performance parameters of your drivers. You will be performing AQL tests on the drivers, and the finished speakers, but you will never have the time to qualify every driver and speaker you produce. That would be too expensive.

So at the end of the day, economics dictates what happens. I would hope that $100,000 custom speaker systems have been broken in, but in my experience in pro audio, they are not. Break-in may happen during the testing phases of a large venue system, but it is incidental. Maybe somebody else knows about those uber home systems.


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## lsiberian

gsmollin said:


> Vance Dickason's explanation is that while the speaker's suspension changes during break-in, parametric shifts that would affect a speaker design are rather small. He recommends a break-in period only to be sure the speaker is not defective.
> 
> My take on this subject is this: If you are designing a new, say DIY, custom speaker system, and you are relying on the exact characteristics of the speakers to tune the enclosures to the exact design you want, then you will be breaking-in the speakers so that the T-S parameters you need have settled to their final values.
> 
> If you are designing a speaker system for mass market sale, then you will design the enclosure for the specified performance parameters of your drivers. You will be performing AQL tests on the drivers, and the finished speakers, but you will never have the time to qualify every driver and speaker you produce. That would be too expensive.
> 
> So at the end of the day, economics dictates what happens. I would hope that $100,000 custom speaker systems have been broken in, but in my experience in pro audio, they are not. Break-in may happen during the testing phases of a large venue system, but it is incidental. Maybe somebody else knows about those uber home systems.


We've had a few other recent discussions on the subject and the consensus is that whatever changes happen in a quality driver are inaudible and insignificant in the design. The favored break in procedure is to watch ones favorite movies while drinking ones favorite beverage and eating ones favorite snack. It seems this method produces a wonderful break in experience and leverages a positive pyschoacoustic effect.


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## ironglen

lsiberian said:


> We've had a few other recent discussions on the subject and the consensus is that whatever changes happen in a quality driver are inaudible and insignificant in the design. The favored break in procedure is to watch ones favorite movies while drinking ones favorite beverage and eating ones favorite snack. It seems this method produces a wonderful break in experience and leverages a positive pyschoacoustic effect.


Ha! I've been using this 'procedure' since I was a kid :dumbcrazy:


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## bill13

*Ear-brain accomodation as important -- Driver Break in - Fact or Fiction?*

Subjective ear-brain accomodation to a particular loudspeaker's sound qualities seems to be a neglected topic.

Often when exposed to a new speaker, I feel that it's too bright or has some other flaws, but such impressions are often mitigated after a few hours listening - giving time for ear-brain processor to 'get used to' the particular sound presentation.


----------



## lsiberian

*Re: Ear-brain accomodation as important -- Driver Break in - Fact or Fiction?*



bill13 said:


> Subjective ear-brain accomodation to a particular loudspeaker's sound qualities seems to be a neglected topic.
> 
> Often when exposed to a new speaker, I feel that it's too bright or has some other flaws, but such impressions are often mitigated after a few hours listening - giving time for ear-brain processor to 'get used to' the particular sound presentation.


But neutral requires no adjustment and that is the goal. Problem is the rooms we live in aren't conducive to that.


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## mdrake

lsiberian said:


> We've had a few other recent discussions on the subject and the consensus is that whatever changes happen in a quality driver are inaudible and insignificant in the design. The favored break in procedure is to watch ones favorite movies while drinking ones favorite beverage and eating ones favorite snack. It seems this method produces a wonderful break in experience and leverages a positive pyschoacoustic effect.


:rofl: You are on a roll, as of late!!!! :T


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## Prof.

> lsiberian wrote: View Post
> We've had a few other recent discussions on the subject and the consensus is that whatever changes happen in a quality driver are inaudible and insignificant in the design. The favored break in procedure is to watch ones favorite movies while drinking ones favorite beverage and eating ones favorite snack. It seems this method produces a wonderful break in experience and leverages a positive pyschoacoustic effect.


:rofl: That's a good one! I must remember that when I get my next set of speakers!

However, there is another side to this "Speaker Break in" situation..
Speakers never reach an ongoing state of constant "flexibility" of movement! 

Speaker drivers are constantly changing their amount of "flexibility" on a day today basis!
This can be proven by turning on your system after it hasn't been used for at least 24hrs, and taking an SPL reading, setting all levels to 75dB..
Then play a movie at fairly high levels for half an hour and then take another SPL reading..
You will find that the previously set levels of 75dB have now changed..The degree of change depending on the efficiency of each speaker..
The difference may not be too noticeable to the ear, however there has been a change in the freeness of the movement in the individual drivers..which would tend to suggest that they stiffen up a little when not played for awhile..


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## angelod307

break in's are fact. not only for speakers, but every peice in between like amps,cables, and cd to dvd players. just my two cents.


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## Lucky7!

angelod307 said:


> break in's are fact. not only for speakers, but every peice in between like amps,cables, and cd to dvd players.


Sorry, but there is absolutely zero factual evidence of any sort of change in use with anything other than transducers such as carts and loudspeaker drivers.


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## lcaillo

angelod307 said:


> break in's are fact. not only for speakers, but every peice in between like amps,cables, and cd to dvd players. just my two cents.


So which is it, just your two cents or a fact? Got any data, or even some sound reasoning to support a hypothesis on anything but speakers? Amps maybe, if capacitors have been discharged for a long while and need to reform the dielectric, but even that is a stretch.


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## gsmollin

Prof. said:


> :rofl: That's a good one! I must remember that when I get my next set of speakers!
> 
> However, there is another side to this "Speaker Break in" situation..
> Speakers never reach an ongoing state of constant "flexibility" of movement!
> 
> Speaker drivers are constantly changing their amount of "flexibility" on a day today basis!
> This can be proven by turning on your system after it hasn't been used for at least 24hrs, and taking an SPL reading, setting all levels to 75dB..
> Then play a movie at fairly high levels for half an hour and then take another SPL reading..
> You will find that the previously set levels of 75dB have now changed..The degree of change depending on the efficiency of each speaker..
> The difference may not be too noticeable to the ear, however there has been a change in the freeness of the movement in the individual drivers..which would tend to suggest that they stiffen up a little when not played for awhile..


Speakers do warm up with use. Most of the changes are electrical, and cause a reduction in efficiency, and some shifts to the crossover responses. This heat gets out of the voice coil through small holes left in the back of certain drivers, and it conducts out through the magnets and pole pieces of all drivers. A driver being driven really hard may experience some warm-up of the spider, but in a home that would be pretty small, probably even hard to measure. I'm sure you can touch the surround on your woofer after it's been driven hard, and it won't be warm.

I haven't heard any claims from manufacturers that speaker surrounds get stiff if they are not used, except if the room gets very cold. Then the surrounds of some speakers can get stiff, and require a few hours to recover. What is the source of your claim that speakers stiffen up when not played.


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## 1Michael

Everyone know that copper wire changes its molecular structure over time, thus causing an audible change in sound:rolleyesno::rofl2:
Let the thread die...


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## angelod307

fact. fact. fact. when power is applied to capacitors, yes they need to form(thus break in), i just replaced some in my ribbons and they sounded very odd for about 5 minutes and as i have been playing them, they have indeed gotten better sounding. but if you guy's do not buy into that kind of stuff, that's cool. i don't buy into thousand dollar cables, but then again, nothing in my setup has the ability to sound that much better with said cables. there are those though, that swear by them. i would say it is what you have been exposed to that really determines what is what. i have heard amps, cd players, preamps that started life on the bright sounding side only to mellow out after many hours of playing. i have been as of lately comparing my pioneer cld-704 laser disc player (late 90's) against a carver sda-490t cd player with tubes in the ouput stages. with the same artist(disc) in both players as i have two copies of the same cd. i a/b them and for the life of have not heard any ground breaking differences. they both sound the same though my pioneer vsx-1014 reciever (used as a pre) driving a carver tfm55 (recently refurbished at hi-tech by roland) to my al-III ribbons. ilogical, but there it is. there is nothing that i can hear that seperates the two as of yet. speaking of the amp, it too has gotten better sounding after a month now of playing. is all this subjective, sure. i can't hear what you hear, as so on. i am going to buy a new jolida cd player, and have been told by several people to get a better power cord as it will make a difference. the manufacturer will not take a return on the player until the breakin period of a week has gone by as they even say the unit will not be 100% sounding until has been played for that amount of time. logical, no. are those people crazy, no. they just have exceeded my knowledge and experience on such things. i would bet that you have not ever even tried any high end stuff to that end. 5k cd players with 10k amps and so on to be that informed on the fact or fiction part of it. but then again, neither am i. so. again, my 2 cents.


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## gsmollin

New ribbon tweeters could have a break-in period, even a warm-up. They are inefficient, and I expect they change parameters with use.

Well tubes do age, not just break in, they continuously change with life, and that sort of thing could be what people hear when they are claiming break-ins on something that lacks this characteristic. 

Your CD player vendor is pretty smart. He knows that the longer you keep something the less likely you are to return it. He knows your ears will break in, not the CD player. And if that CD player is so "high end", why doesn't it come with a better power cord?


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## Theresa

I experienced a dramatic break in with my Sennheiser HD600 headphones used with a Asus Xonar Essence STX as a headphone amp. I thought I had lost my headphones (sister came to clean while I was sick) and replaced them with identical ones. The new ones sounded very different for the first couple of hundred hours but now they sound the same. I found the older ones and did AB testing, not ABx but the sound was very different.
I generally don't believe in high end nonsense with cables and such but it makes sense to me that a mechanical system such as headphones would change quite a bit over time.


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## bambino

I believe it to be fact. Many of the Drivers i have purchased or seen state that there t/s parameters are before break-in or sometimes after. And weather or not it makes a differance i know first hand especially with subs that the suspension loosens up after awhile.:T


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## Lucky7!

angelod307 said:


> when power is applied to capacitors, yes they need to form(thus break in)


This applies to electrolytic caps only and takes a few seconds to a few minutes at most.

Rather than multi quote away, power compression in drivers is not break in.


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## Theresa

Your right, there is no evidence for any sort of break in with electronic components. Its the mechanical properties of transducers that change with break in. People like to think they can hear whats not measurable but it purely placebo effect. Placebo effect is very real and occurs all the time, especially when someone spends a lot of money on something like cables. There is this whole subculture that's entirely made up of people with too much money and too much time to fantasize about what might sound better. I used to love reading Stereophile but the off the wall talk of the entirely subjective was too much for me. There's even a language that's developed around it. I wonder if its somehow linked to testosterone as it seems to affect only males.


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## 1Michael

The first thing we audiophiles learn is to throw in the garbage all of the 'audiophile language' we picked up from from the mass marketing monkeys, and self absorbed golden eared wanna bees, that write equipment reviews for certain magazines, that make their money from the same advertisers they are reviewing equipment for:bigsmile:
Not to mention any names &$^#()phile.


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## Moonfly

If a new drive has a stiff suspension, that softens when its starts to be used, and this is factored into the design, then driver break in has to be real. The driver will move more easily under a given load once the tight new materials start to loosen up, which in driver terms should mean a deeper/warmer/more bass driven character. Its only like new shoes that soften up.

I for one subscribe to those effects, and having tested a fair few new drivers, I'm pretty sure I notice it happen too. This can be measured, because the TSP's of a brand new driver are different to what they will be after 100 hours use, with the driver upto operating temperature, and played at a good volume. Ive not read this thread, but thats where I stand on that. How audible it actually is I guess depends on the driver and its application, but I think the effects are most noticed at lower frequencies, so the less they are present, I would say the less they are noticed. I cant say if a tweeter has the same break in, or that Ive ever noticed it on tweeters, but subs and bass in speakers, I have.


----------



## angelod307

wow, how could i have not seen it. you know those things called atoms have to be a fad like the atom bomb. you can't see them (Atoms) with the naked eye. yet they bounce around when they are conducting energy. how could i have missed it. therer could never be any kind of change on a molectular level in things. kind of like the earth being round when we all know it's flat and you will just fall off the edge when you get there. stupid placebo people that call themselves audiophiles. how dare they say such things after they spend all that money and look for some rational explanation for spending it and what the benifits are. how dare them...............


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## TypeA

buggers said:


> and self absorbed golden eared wanna bees, that write equipment reviews for certain magazines, that make their money from the same advertisers they are reviewing equipment for:bigsmile:
> Not to mention any names &$^#()phile.


Doesnt a public consensus of a good or bad product make this almost impossible? Dont publications loose creditability if this is shown to be true? Can you cite specific examples of products that, you believed, clearly received scores higher than they should have from these big publications? I realize all reviews, 'pro' or otherwise, must be taken with a grain of salt and its all subjective, but Im still curious what makes you say the big boys are willing to sacrifice their name in pursuit of the almighty dollar.


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## 1Michael

TypeA said:


> Doesnt a public consensus of a good or bad product make this almost impossible?


No. Can you spell Bose? I will let you do your own homework, that is the y in diy. I have read certain publications for over 25 years and it is not difficult to see what a publication is really about...


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## TypeA

My bad, I should have used the term an 'educated' public consensus. For those with a basic education, taking audio advice from a Bose owner would be a lot like taking financial advice from a poor man. But Ill do the research into your claim.


----------



## Andre

I had Bose 901s in 1976 and they played Frank Zappa to my satisfaction.

That out of the way, there is probably a break in for everything from toasters to amplifiers. Personally I believe that if the human element notices a difference its because They are now broken in to the particular item. Sort of like not smelling the pigs anymore after a week on the farm.


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## Theresa

I recently built three monitors and two subwoofers. I noticed a big change after a few hours of use. I also compared a new pair of Sennheiser HD600 with a pair a couple of years old and heavily listened to. Bass was noticeably weaker in the new pair. Its a matter of flexible parts loosening up to meet their operating state.
Further, many loudspeaker companies do burn in their drivers, such as Exodus from whom I recently purchased a Shiva X2 and Tempest X2 and ScanSpeak does too.


----------



## Theresa

deleted by poster


----------



## tshifrin

Thanks to all for this discussion; I learned a lot about the theory and practice of driver break-in. 
Now I intend to play with it myself:
I just received a new sub driver which measures very differently from the manufacturer's published specs, so I'll try some of the break-in techniques mentioned in this thread and see what the results are-
Nothing like some direct experience to match my State motto: Show-Me.

Tom


----------



## Oktyabr

Fact. Good headphones, like the AKG-K701, really see an improvement with at least 100 hours of break in. Same with the full range drivers I've played with. Can't say much about commercial products although I believe some companies even break in the speakers before shipping.


----------



## Danny Richie

Hey fellows, 

I know this is an old, and for some reason, still ongoing discussion. 

I posted some measured data on this subject several years ago that can still be seen on our web site. 

Here: http://www.gr-research.com/burnin.htm

And the real myths about burn in are taken on here: http://www.gr-research.com/myths.htm

Enjoy.


----------



## Dub King

Whenever I discuss breaking in speakers, the analogy I like to use is shoes. There is a break-in period that is related to the materials used and overall pliability. The process might take minutes, hours or days. Speakers are sneakers, subwoofers are boots. With subwoofers, I've measured an increase in (extreme) excursion at the same output levels over the first 10-20 hours. This correlates to frequent reports of 'improved low frequency extension'. With regular speakers, I'm not so sure there's any break-in to notice unless the speakers are used full-range and have exceptional bass extension... basically any speaker with large, high-excursion woofers. I'd wager more than a few dollars that in a new system, the subwoofer is the only component people actually hear 'break in' and that sometimes the improved overall dynamics are credited to speakers or some other component.


----------



## Danny Richie

Actually Dub King the smaller drivers go through just as much mechanical compliance change as the larger ones. If you follow my links above you can see some measured time frames on a group of drivers that range from 5.5" to 6.5". 

What most people actually hear is also contributed to the electrical burn in as well. Wire, dielectric material, films, etc, all go through a forming period that alters the signal transmission over the first 40 to 50 hours on some materials and up to 500 hours on material like polyethylene or Teflon. 

From a good 400 to 500Hz and up it is the burn in changes of capacitors that are most discernible. 

Speaker cables, interconnects, power cables and even electronics also go through these same effects.


----------



## Dub King

I don't believe power cables and interconnects go through burn-in. I'm open minded, but not to the point of believing in magic. I do agree smaller drivers go through compliance changes as well, and that any solid-state component that relies on chemistry will also show very small changes in performance, although I question whether this can really be heard. Surely this has all been debated by people smarter than I.

I'll tell you one thing... I've only met audiophiles and marketing/sales folks who believe in cable break-in. I don't run into producers or musicians or recording engineers who believe any of that. You will find me to be in the 'same as coat hangers' camp when it comes to running electricity through metal wires, and nothing in the last 30 years of music listening has managed to challenge that impression.

Subwoofers go through the greatest changes, that's where break-in has the most impact - followed by woofers.




Danny Richie said:


> Actually Dub King the smaller drivers go through just as much mechanical compliance change as the larger ones. If you follow my links above you can see some measured time frames on a group of drivers that range from 5.5" to 6.5".
> 
> What most people actually hear is also contributed to the electrical burn in as well. Wire, dielectric material, films, etc, all go through a forming period that alters the signal transmission over the first 40 to 50 hours on some materials and up to 500 hours on material like polyethylene or Teflon.
> 
> From a good 400 to 500Hz and up it is the burn in changes of capacitors that are most discernible.
> 
> Speaker cables, interconnects, power cables and even electronics also go through these same effects.


----------



## Danny Richie

I wish you were close by. I'd change the way you think about everything by letting you listen to some comparisons. I have not had a visitor yet that couldn't easily hear the difference in a cable change whether it be power cables, speaker cables, or interconnects. 

I can even let you get used to the system and swap out just one pair of interconnects for a fresh pair (no burn in) and again the difference is not hard to hear, especially if you know what to listen for. 

There is a challenge here that you might be interested in: http://www.hometheatershack.com/for...-resistors-make-difference.html#axzz2CF7wwm4U 

And cable break in isn't a believe in or not believe in type of deal. You either have experienced it or you have not.


----------



## Danny Richie

And typically it is harder to hear the mechanically changes in compliance of a sub woofer than a smaller driver. As the compliance softens it is kind of like air shocks on an old car. If you put a lot of air in the shocks then the ride is firmer and it can take longer for the car to quit bouncing after hitting a bump. With less air in the shocks the ride gets softer and settling time is less. 

Woofers are much the same way. As the compliance softens it alters the settling time of the woofer. So it tends to recover faster from the input signal. This is why many people note that the mid-range sounds smoother, lusher, more natural, and with less congestion after burn in. 

With the small driver the settling time can decrease in some areas by 1 or 2ms pretty easily. And if the total settling time was only 6 or 8ms to begin with then this is pretty significant and easy to hear. 

On a real heavy sub the softening can allow a little deepening of the output, but a 1 to 2ms decrease in settling time might not be as noticeable when setting times could be MUCH longer due to the amount of mass and stored energy of the heavier woofer. Room resonances and cabinet wall resonances can also easy mask the slight added clarity that one might get from a sub after a good burn in period.


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## Dub King

I'm sure you have a mighty fine demonstration, I don't get down to Texas much. Thanks for the link, I think most DIY speaker builders would agree with the upgrades you performed on that speaker. As a producer I have to say that the thinking that goes on at the consumer end of things is sometimes amusing, far too much emphasis is placed on the things that matter least. :rolleyesno:

I have my opinions, I don't claim they are facts. My opinion is cable burn-in - insomuch as it can be discerned by the listener - is purely in the realm of psychoacoustics. The main exception I'd grant is if a cable is of the wrong impedance (in the case of connects) or of insufficient gauge to perform the assigned task (in the case of power cords and speaker cables).



Danny Richie said:


> I wish you were close by. I'd change the way you think about everything by letting you listen to some comparisons. I have not had a visitor yet that couldn't easily hear the difference in a cable change whether it be power cables, speaker cables, or interconnects.
> 
> I can even let you get used to the system and swap out just one pair of interconnects for a fresh pair (no burn in) and again the difference is not hard to hear, especially if you know what to listen for.
> 
> There is a challenge here that you might be interested in: http://www.hometheatershack.com/for...-resistors-make-difference.html#axzz2CF7wwm4U
> 
> And cable break in isn't a believe in or not believe in type of deal. You either have experienced it or you have not.


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## fwbutler

In late January I built a set of 40" folded horns using a 4" driver. They included horn tweeters. I am not using a crossover just a 10 uf cap as a hi pass filter for the tweeter.
Because of a project that I was working on I did a number of spectral scans every few days. After a day of testing the speakers at *90 db* :hsd:, my wife and I both noticed a change in the sound of the speakers. There had not been a change in the 4 months of use before that. 
Here are scans from the start of testing and after the change. I do not see a change, but can hear one.


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## grokaudio

Sorry all, just found this thread - and haven't read through all posts.

For what I can tell - with raw drivers - building own cabinet - and designing crossover, breakin is a must...

see http://www.hometheatershack.com/forums/rew-forum/67216-checking-mdat-impedance-files.html


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## Frank D

Could one not use distortion measurements when drivers are new and then again say after 50 hours break in to see the difference of break in? REW has speaker distortion measurements.


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## Danny Richie

Frank D said:


> Could one not use distortion measurements when drivers are new and then again say after 50 hours break in to see the difference of break in? REW has speaker distortion measurements.


The differences you hear are not found in distortion measurements. The differences can be seen in the spectral decay though. As the suspension softens it changes the setting time causing less stored energy and smoother more relaxed sound.


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## Frank D

Danny Richie said:


> The differences you hear are not found in distortion measurements. The differences can be seen in the spectral decay though. As the suspension softens it changes the setting time causing less stored energy and smoother more relaxed sound.


Thanks Danny.

So for a new 12 inch coaxial speaker what would you say is a fair break in period using a break in track? 50 hrs? More? Also what is an ideal break in spl level ie 10 db below reference ok?


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## Danny Richie

Frank D said:


> Thanks Danny.
> 
> So for a new 12 inch coaxial speaker what would you say is a fair break in period using a break in track? 50 hrs? More? Also what is an ideal break in spl level ie 10 db below reference ok?


In my experience of testing and measuring the T/S parameters after various amounts of burn in time I see this pattern. Imagine the fresh driver is at point A and complete burn in is at point B. Every time you double the amount burn in time you move half way to point B. So in the first hour you move pretty far. I'd say close to half way. But eventually you are putting a lot more time on them and seeing very little real change. 

With some drivers it is really hard to hear much change after 40 hours or so. With some that settle range where it is hard to tell any difference come at 80 plus hours or so. 

Also, how hard you're working them in that burn in period makes a difference as well.


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