the myth of loudspeaker "break-in"
Speakers and speaker drivers do not “break in.” Acoustic measurements prove this. Experts like **** Pierce have proved this. If a driver measures differently after 20 hours of use, then it has been damaged, thermally or mechanically.
“Break in” is the idea that a device requires a certain amount of sheer wear before its performance settles in to some normal baseline. Speaker drivers don’t require this, because there are essentially no moving parts rubbing against each other. There are parts flexing, but there is no basic wear taking place.
Speakers do, of course, wear out. This takes a long time and depends on the materials used in the drivers. The elasticity of the surround and spider and the stiffness and internal damping of diaphragm do, of course, slowly change over time. Solvents off-gas and materials become embrittled. Humidity and UV take their toll. So yes, speakers will measure differently over time. But is a gradual thing and it takes years. This is not “break in.”
A good analogy would be the suspension of a car. The properties of the car’s suspension are somewhat different when it has been stationary for a few hours than when it is driven. When the car starts to move, the first 30 seconds or so of flexing of the suspension are a little stiffer and more damped, but the system of springs, ball joints, sway bars and dampers all very quickly get past their stiction points, heat up, and begin behaving normally. This happens very quickly.
The same idea applies to speakers that have been sitting idly for a while. It only takes a few seconds of exercising them for the suspensions to loosen up and voice coils to heat up and the drivers begin operating normally.
Loudspeaker “break-in” is definitely one of the more pervasive myths in audiophile land. And please don’t accost me with testimony about your personal measurements that prove me wrong. I have also made such measurements and they do not support the loudspeaker break-in believers. And I am in the same camp as the experts. You know, guys with degrees in physics who have written peer reviewed papers on this stuff.