AudioBanter.com - View Single Post - Loudspeaker break-in

Stewart Pinkerton wrote:

On 26 Sep 2004 14:51:46 GMT, "L David Matheny"
wrote:

"Stewart Pinkerton" wrote in message
...
snip
My only concern is - how will I know when they have stopped
breaking in, and started wearing out? You can't reasonably have
one without the other.....................

It's all the same. You're just trying to move into the long (we hope)
linear part of the wearing-out curve.

Perhaps so. But, given that people who've investigated this
possibility, such as Tom Nousaine and the redoubtable Dick Pierce,
seem to regard 'break-in' as a non-event after the first couple of
*seconds*, and given others (such as the OP himself) who claim never
to have observed 'wear out', do we have any real*evidence* that
break-in really exists? If not, then surely a search for 'the best
break-in CD' is as pointless as arguing which shade of green is best
for painting the edges of CDs?

--

Stewart Pinkerton | Music is Art - Audio is Engineering

I have conducted several experiments in break-in covering periods as long as
150 hours. What happens is that you can measure a fall in system or driver
resonance by several percent along with an increse in compliance of a like
amount immediately following an extended break-in period. However if you allow
the driver/system to rest for several hours you'll find that the unit returns
to its 'fresh' values.

Further if you model either set of parameters you'll wind up at the same
enclosure requirements for either condition (a lowered Fs and an increase in
compliance will be off-setting.)

The "most" you can say about extended break-in is that at most a system/driver
may "warm-up" but even then its sound will not change.

On the other hand, the only negative thing about 'warm-up' is that it can be
dangerous in that you can damage the speaker by putting too much currrent into
the voice coil for an extended period and/or rip suspension components with too
much power.

Noise signals are by far the most dangerous. I was involved in a trial testing
the EIA 426B power handing standards and found it was possible to actually melt
a plastic cone using their long term noise signal.

If one is to try-nature with break-in I'd strongly recommend against using
noise (as is often suggested) and especially against using the off-polarity
test using a pair of systems placed face-to-face out of polarity to reduce the
ambient noise of break-in with a noise signal. It's just too darn dangerous;
full or partial band signal with equal amplitude over the entire bandwith,
unless you 'like' the smell of softening voice coil glue.

At DLC Design where they use DUMAX to test linearity of loudspeakers they
sometimes need a short break-in period to allow a speaker that has been stored
on its back to restore its natural rest position .... and this takes less than
a minute.

What's the "safest" (as in using a condom for contraception even if you've had
a vasectomy) break-in signal? The most comfortable condition is a woofer driven
with a sine wave near its resonant frequency in free-air with enough power to
allow excursion to attain perhaps half to 2/3 stroke for a relatively short
period while you remain in attendance.

But even so if there really were an important "break-in" period wouldn't your
speakers simply just break-selfs-in during normal use? The only time this might
be an important issue is when the break-in period might exceed the
product-return time limit.

I once tested a product where the owner manual suggested that the speaker would
'improve' over 150 hours of use. I called a local dealer and asked what the
store return policy was. As it turned out that was 7-calendar days (meaning
that a speaker purchased on Monday had until Saturday to get returned but if
you bought on Tuesday you had a full week) so that meant that in order to
'reach' the speaker's full potential a new owner would have to use/break-in the
product for 6.25 days non-stop to find out if they 'sounded' as good as he was
lead to believe..

This condition is but one of the real reasons that break-in has become an audio
urban legend. I understand both the conditions where this might be important.
First it tends to reduce buyers remorse; but it also tends to limit customer
choice.