Driver Break in - Fact or Fiction?

[toecheese]

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]

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]

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]

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]

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.