Driver Break in - Fact or Fiction?

**toecheese** · **10-27-07, 06:54 PM**

Quote:

drf wrote:

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...

**FoMsound** · **11-13-07, 01:32 PM**

Quote:

Scuba Diver wrote:

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.

**Anthony** · **11-13-07, 01:40 PM**

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.

**drf** · **11-15-07, 03:44 AM**

Quote:

Anthony wrote:

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.

**phaseshift** · **01-27-08, 11:30 AM**

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.

**08-19-08, 03:10 PM**

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

**Bill Fitzmaurice** · **08-19-08, 09:20 PM**

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.

**thewire** · **08-20-08, 03:39 AM**

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.

**andru** · **08-20-08, 06:08 AM**

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

**Bill Fitzmaurice** · **08-20-08, 09:29 AM**

Quote:

andru wrote:

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.

**looneybomber** · **08-20-08, 02:07 PM**

Quote:

Bill Fitzmaurice wrote:

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

**andru** · **08-21-08, 01:16 AM**

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

**SQCherokee** · **08-21-08, 02:01 AM**

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.

**Bill Fitzmaurice** · **10-17-08, 10:16 AM**

Quote:

SQCherokee wrote:

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.

**Kevin Haskins** · **10-17-08, 12:47 PM**

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

**Ricci** · **10-17-08, 03:24 PM**

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.

**Kevin Haskins** · **10-17-08, 03:36 PM**

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

**Bill Fitzmaurice** · **10-17-08, 05:44 PM**

Quote:

Kevin Haskins wrote:

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.

Quote:

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.

**Kevin Haskins** · **10-18-08, 12:56 PM**

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

Kevin Haskins
Exouds Audio
www.diycable.com

**ISLAND1000** · **10-18-08, 01:06 PM**

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.

**kryptonitewhite** · **11-13-08, 06:43 PM**

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??

**pinkjimiphoton** · **11-14-08, 06:19 PM**

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

**Ricci** · **11-14-08, 06:31 PM**

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.

**kryptonitewhite** · **11-14-08, 06:36 PM**

can you even bottom out those 18" 06' XXX's?

3000 watts 30Hz on up, disgusting

er scary?

**Ricci** · **11-16-08, 05:17 PM**

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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