This is getting interesting. I think I heard three "actual test results" mentioned -- one attributed to Paul Barton, one attributed to Craigsub, and references by Donaldekelley to other people's break-in experiences with replacement tweeters.
Dr. Barton's test involved measuring frequency response over a long period of time and finding it unchanged. My guess is that if there IS a "break in effect" it would be too subtle to jump out in a frequency response chart. I don't think those tests are sufficient to prove or disprove the break-in theory.
Craigsub's test was more directly relevent to this topic -- a/b testing of a "broken in" vs "out of box" speaker. The speakers in question were "Onix R2"s (don't know anything about these, sorry), not sure about their drivers. This "break-in thing" seems to be more relevent to metal drivers.
Donaldekelly mentioned that there were some discussions about people who replaced a tweeter and "had to go through the break-in process again". This sounds worthy of more investigation -- surely the replacement tweeter would sound quite similar to the part it replaced unless there was either a design/production change or some kind of break-in effect happening (??).
To summarize :
- Dr. Barton / PSB frequency response over time -- inconclusive
- Craigsub "old vs new speaker A/B test" -- more conclusive but break-in seems to be more metal-driver related, don't know if Onix drivers are relevent or not
- Donaldekelly "replacement tweeter" break-in -- seems to support break-in theory but only a casual mention
There seems to be a bit too much support for the "metal drivers need break-in" theory to dismiss it out of hand. I have owned significantly different speakers over the years (homemade Philips/KEF => Quad ELS => original PSB Beta => Rogers LS3 + sub => no-name "I got married" speakers => Axiom) and *thought* I had a pretty good handle on the whole "breaking in the brain" thing.
I was surprised how the Axiom sound seemed to change over the first couple of weeks -- specific high-frequency sounds really did seem a bit unpleasant at first, enough so that I swapped L&R to see if I had a bad tweeter (nope).
I was always a big believer in the "if they sound crappy new they're gonna sound crappy forever" school of thought, but I really think the M2 high range smoothed out significantly.
Oh well, maybe it was just the placebos kicking in. I have been taking quite a few of them recently
Anyways, thanks to everyone for the great input. I expected to be shot down much more emphatically -- so far I can't say that I have seen conclusive evidence either for either side of the argument.
I wish I had 5.1 electronics -- this would be a great excuse to pick up another pair of Axioms and do some A/B testing. Problem is that I would probably want to try M22s this time so still wouldn't get the exact A/B comparison.
If anyone is thinking about buying some M2i's in the Toronto area let me know -- I can bring mine over when you unpack yours and we can A/B 'em.
Thanks again everyone.
JB
