Subwoofer break in

IIRC, break-in has mostly to do with the "loosening up" of a driver's surround and spider and has nothing to do with any exotic ritual (facing the speakers toward each other, etc.) or specific length of time.

I can't recall ever noticing a change in the sound of speakers when they broke in, but I do recall noticing that my PB12-NSD sounded a bit different / better after ~10 hours of playing. Nothing scientific, just an observation I made at the time.

Drivers do break in. You can accelerate the process with a tone generator and have the drivers working to spec overnight, or you can just use them and they'll be fully broken in after 40 hours or so. The only myth lies in advertising that claims 100 hours or more are required for a particular speaker model to break in. Any manufacturer that spouts that nonsense should not be rewarded with your business.

I often wonder if this so called "break-in" period is really a break-in for the speaker or a break-in the users ears. I think our ears adjust to the new sound and it becomes more familiar over time.

Manufactures spouting nonsense about 100 hours, but you saying 40 hours is not nonsense? How so?

Its all nonsense.

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They are mechanical devices, so not hard to think they can benefit from a little break in on the parts that move. I think the post about your ears becoming accustomed to new equipment probably has merit as well. I think my new subs sounded better after using for a while (didn't count hours, but think it was well within 40).

Driver break in is measureable. Fs is usually lower after a break in period. I think the bass will become a little fuller sounding and treble may have some shrillness toned down some.

Just saying, FWIW, if it moves within itself, it is going loosen up; break in; lose it's tightness. It's like this for clothes, bearings, pneumatic struts and speakers.

Can you please provide an example of such measurements.


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

Can you show examples of how its nonsense?

Quote from the link "does not prove noted subjective differences in the perceived output, or how a speaker sounds"

I've never done this, I just let 'em cook while listening, but facing the speakers toward each other and switching polarity on one cancels out much of the sound. This allows you to break in the drivers without disturbing the rest of the house.

I never said the differences in sound is measureable only that driver break in is measureable. You argued against driver break in as nonsense, fact is driver break in is something that can be measured (driver parameters change). Whether someone thinks, believes, or perceives a SQ difference doesn't matter, FACT is break in is measureable, so how is that nonsense?

Is it your opinion that driver break in is nonsense or do you have anything factual to back that up? Saying you listened to a speaker and never noticed a difference before and after doesn't count, thats subjective and makes no more sense than someone saying the exact opposite that they noticed a difference after several hours.

The measurements I was looking for were in regard to audible changes after so called burn in, which is what the OP was asking about. I have never seen a double blind test showing differences because of break/burn it.

If I had read your post carefully I would have realized you were talking specifically about the measured change in the woofer itself. Sorry about that and thanks for the data links.

And I agree with you that no way can any one person rely soley on their listening experience. Just too many things change over time (our hearing, noise exposure from the day, temperature, humidity, etc) to say the "change" is because of speaker break in.


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What do you do for a living? Now look at my profile and see what I do. If you want to offer an expert opinion you first have to be an expert. Measurable in that woofer Fs drops on average by 10%, as does Qms, and therefore so does F3. That's of more than slight significance.

Then surely you can provide data showing a DBT where the differences were audible and detected by listeners.  And the data showing how much more audible difference there is from 40 hours to 100 hours of break in.

 

Sorry, I don't play the credentials game, just asking for your data.

I wonder if there has been such a dbt test...something for you to look into rather than just asking things to be delivered to you?

Can you provide anything that shows there was no audible difference between 40hr and 100hr? Seems your more interested in proving your right and everyone else is wrong. You said its nonsense SHOW use how you came to your conclusion.

Did you buy speakers that the manufacturer tests before they ship out of the factory or did you buy from a manufacturer that ships them out after assembly?

I've had speakers that was tested before shipping with some time on the woofers and nothing was noticable. I've bough from companies that do not test the speaker before shipping out and I can tell you theres a difference in the bass between the first time listening to them vs some hours later.

Tried the same cd when I set the speakers up and it sounded as if there speakers had a 150hrz crossover. Used a 24-7 music channel on all day for about 9hrs while I was gone. Re tried the same cd, same song and the bass was there full and have authority in the midbass.

I can see where/how this thread is going so I'm going to bow out. SorryIif my "all nonsense" comment ruffled feathers and agree I did not provide any data. I just found Bill's comment stating 100 hours is nonsense but we should believe him when he says 40...with no data provided. I have never seen a DBT showing test showing a difference in speaker or woofer breakin. If some one can locate one then great! Until then, that his how I come to my conclusion.

To the OP, keep in mind no one in this thread has provided any data showing it is needed, so make your judgement on that.

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I'm going offer up a "guess" here, as to why there are no DBT's.....because it's never been in question until now? As I pointed out, it's normal to expect mechanical devices to have a break-in period.

Another guess on my part, in the case of speakers, DBT's come into being, when doubt enters the game? An additional guess on my part, the "experts" are not in doubt.

(Everything in my above was conjecture; guessing.)

Guys,

For whatever it's worth, I have witnessed noticeable improvement in SQ in speakers with passive radiators. Particularly, I am referring to Deftech Studio Monitor 450s, and three different pairs that I bought at different times.

They did not sound great when I hooked them up for the first time (kind of harsh on the ears) but after I left pandora running overnight the sound improved a lot by the morning. When I returned from work that night I noticed further improvement and then they stabilized. I had exactly the same experience with all three pairs.

I was not constantly listening so it was not my ears adjusting.

If you check the def tech owners thread you will find others with a similar experience.

Note that I did not observe such a drastic difference with any of my subs (e.g., an Epik Legend, or my recently purchased JTR Captivator S2)

It's the same with headphones and IEM's.

This insistence on a measurement for speakers' break-in be delivered to you or it's nonsense demand was just annoying when so many other things about speakers are hard to measure, and funny how so far you're the only one who seems to think it doesn't exist (unless I don't remember someone else saying that) although it seems you might doubt it and need someone else's measurement to make up your mind, too; if someone did have a dbt test would you eat your nonsense statement? I doubt anyone's really all that interested in it to bother with such a test. I'd not pass judgment on a speaker without giving it some time in any case. They are mechanical and many mechanical things benefit from break-in, so it's not like it's "out there" like one 16g wire is magically better than another. Bill's experience, with some examples of where it takes place, just backed up my subjective experience for example.

To some extent, but not nearly as much with woofers. By the same token midranges require less break in than woofers, and tweeters less still, all having to do with how much excursion is required of the suspension. Break in is most critical with ported and PR cabs, as they're tuned to work with the driver specs as they exist post-break in. As for passives, in their case both the woofers and the PRs break in, as both have suspensions, so they may be even more noticeably affected. IMO speakers should be broken in at the factory, but that takes time, and time is money. In the case of those who claim they need 100 hours or more, true. I've seen figures as high as 400 hours, and all that's changed between 40 hours and 400 hours is that the free return period has expired.
Edited by Bill Fitzmaurice - 10/28/12 at 6:53pm

That 'experiment' was done in a more rigorous fashion by David Clark in "Precision Measurement of Loudspeaker Parameters", which was published in the March, 1997 in the JAES, a referreed journal. While Fs falls, Vas rises and are related to changes in the compliance. This has a 'nulling' effect. However, if one measures these parameters after the speaker has rested, they revert back to their original values. While the changes may appear large, examination of various drivers indicates that variation in the T/S parameters vary greater than the changes that occur during playing. To quote or read the article is one thing. To understand it, is quite another. Let us also note that the author of that article makes mention of electrical burn in too. To take him too seriously or give some of his comments too much weight because they are printed on the web would be a pity. After all, the web is a source of vandalism as much as it may be a source of information.

That's not the case. The specs will creep back towards the original values after a period of rest, but they never go back to the original values. Moreover, once the initial break in has occurred the time frame for the spec values to fall back to the post break in figure is reduced from hours, if not days, to minutes, if not seconds. With each subsequent use the amount of creep back is reduced, as is the time required to get back to spec.
Also noteworthy is that the break-in process never stops, because the surround and spider continue to grow softer with use. I had one woofer that measured 60Hz Fs out of the box, and after initial break in it came down to the 53Hz spec. I used this same woofer in a number of cabs, swapping it out every few years. and with each subsequent testing the Fs had dropped a bit more. The last time I measured it was 20 years after the initial break in, by then Fs had dropped to 46Hz.

Reason would tell you if it is electromechanical it will break-in (loosen up) over a given amount of time whether thats audible or not to the listener depends on ones hearing.

Our accurate recollection of what we hear has a very short life, measured in hours if not minutes, so the long term effect of break in isn't generally all that noticeable. You'd have to hear a broken in versus not broken in speakers side by side to be aware of how significant the difference can be.

Let's say I take a rubber band and stretch it, but not so far that I stretch it to the point of permanent deformation or breaking. IOW, I stay within the rubber band's elastic region. If I measure the length of the band before and after a long series of stretchings it will be somewhat longer. But after a period of rest, the material cools down and the polymeric molecules return to roughly their original configuration and the rubber band's measurements will have come back to their original value.

Something else to keep in mind is whether the changes that one measures fall within or outside of driver to driver manufacturing variances.