Floyd Toole: Sound.Reproduction.The.Acoustics.And.Psychoacoustics.Of.Loudspeakers.And.Rooms page 353:
"
In parts of the audio industry, there is a belief that all components
from wires to electronics to loudspeakers need to
“break in.” Out of the box, it is assumed that they will not
be performing at their best. Proponents vehemently deny
that this process has anything to do with adaptation, writing
extensively about changes in performance that they claim
are easily audible in several aspects of device performance.
Yet, the author is not aware of any controlled test in which
any consequential audible differences were found, even in
loudspeakers, where there would seem to be some opportunities
for material changes. A few years ago, to satisfy a
determined marketing person, the research group performed
a test using samples of a loudspeaker that was
claimed to benefi t from “breaking in.” Measurements
before and after the recommended break-in showed no
differences in frequency response, except a very tiny
change around 30–40 Hz in the one area where break-in
effects could be expected: woofer compliance. Careful listening
tests revealed no audible differences. None of this
was surprising to the engineering staff. It is not clear whether
the marketing person was satisfi ed by the fi nding. To all of
us, this has to be very reassuring because it means that the
performance of loudspeakers is stable, except for the known
small change in woofer compliance caused by exercising
the suspension and the deterioration—breaking down—of
foam surrounds and some diaphragm materials with time,
moisture, and atmospheric pollutants. It is fascinating to
note that “breaking-in” seems always to result in an
improvement in performance. Why? Do all mechanical and
electrical devices and materials acquire a musical aptitude
that is missing in their virgin state? Why is it never reversed,
getting worse with use? The reality is that engineers seek
out materials, components, and construction methods that
do not change with time. Suppose that the sound did
improve over time as something broke in. What then? Would
it eventually decline, just as wine goes “over the hill”? One
can imagine an advertisement for a vintage loudspeaker:
“An audiophile dream. Model XX, manufactured 2004,
broken in with Mozart, Schubert, and acoustic jazz. Has
never played anything more aggressive than the Beatles.
Originally $1700/pair. Now at their performance peak—a
steal at $3200!”
"
