Do you think driver “break in” is real?

Do you think “high end” drivers and crossovers typically need a “break in” period before they sound their best?  I ask because, I believe I’ve experienced this first hand in a very significant way. I replaced the tweeters (same exact brand and model as original) in my ACI Sapphire 25 year anniversary edition speakers and for the first week I thought I’d lost my all time favorite speakers. I was depressed!  So I just kept playing them…  finally after a couple weeks, I’m literally stunned and blown away at how incredible these speakers sound. Completely different than the first 30 or 40 hours after I put in the new Scan Speak tweeters. So I say break in period must be real - at least for some drivers. Has anyone else experienced this to a degree that is unmistakeable?  
Crossovers too?  I just rebuilt the crossovers for a pair of ACI Sapphire XL’s (using highest quality components- same values) and so far they sound mediocre. Hoping for the same result as my other Sapphires but after about 20 hours - no noticeable difference - and they do not even sound as good as prior to crossover rebuild. They sound flat, too bright with poor imaging - but for 10 to 15 years they were pretty great sounding speakers. Thoughts on crossover break in?? 
Thanks to anyone who responds!!  


Built a set of speakers in Juiy. They sound different now than then, subjectively Better (now at around 200 hours of use)... as experienced by a 1/2 dozen people in our Vinyl Club, family members and myself. If it is a Placebo Effect, the PE has been consistant through variously aged people, the frequency of their exposure, Digital sources, Analog sources, different placement in the Room and other variables.

A very impressive Dummy Treatment...we are all fooled and happier for it. 

I merely note that if Zu Audio can offer free break-in before they ship to you, at their price points, it seems pretty lame for more "upscale" manufacturers to not do the same.  Speakers ought to be turnkey components.  You buy them, you plug them in, and you listen. You smile if they make you happy or you send them back if they don't. 

Forcing customers to do such long break-in periods does start playing into the psychoacoustics of mental accommodation, wherein you think they sound better because you want them to, and you've become used to them, not because they do by any objective measurements. 

And I have to ask you this:  If speakers change so much after 200 hours of use, what then of the next 4000 hours? How does a mass-spring-damper system "magically" know when to stop changing, or does it?   

Certainly physical components, yes.

But electrical current certainly changes wires and whatnot over time.  It’s called “electro migration” and eventually wears out wires and connections. Takes a ver long time.

It makes perfect sense that this process works on the front end for “good”.

No, I don't believe they do "break-in," What I do believe is people becoming accustomed to the speaker's sound. But lots of people also believe cables can be broken in, so there's that. 🙄

Hello sal1963!  sadly, "highest quality capavitors" is a bit vague. Unless they are Delunds, which are hideously expensive, that could be a problem. I have tried many different brands of capacitors (including Delund) and I have found that Mundorf KRPs work very well indeed and are reasonably priced. There are better sounding caps (Delund for sure) but the slight difference is not worth the price. I say this as a retired senior and serious, solder iron weilding, enthusiast. I'd tell you what brands they beat, but I am out of my house due to a flood and don't have acces to my amps, etc which are all in pods! The quality of the solder used, method of attachement of parts (super tight physical bonds before soldering) and the wire and terminals used in connecting the amps and speakers all matter too. I was shocked with the improvement made when I replaced connectors using ferrous metals with brass & copper parts! It made more difference that capacitors! When you consider that just in the wire from the amp to the crossover you might have four ferrous mental spades or banana plugs - then the terminals themselves on the amp and speaker boxes, the internal wire in the the speaker box - do the wires go from the crossover to the actual flexible wires to the driver's voice coils via a steel terminal attached to the speaker frame? - egads! (Fortunately my speakers are open baffle LX521s designed by Sigfried Linkwitz and it's easy to get to all the connections.) Make sure the wire from the crossovers actually touches the flexible wires going to the voice coils! Use silver solder. Solid silver wire used in jewelery making is available from jeweler supply houses at reasonable prices. it's not insulated, but you can figure that out. Details make a big difference! Enjoy the musc!