loudspeaker somehow – but we do our
best to build in enough protection to
cover as many conditions as we can.
How
is it pulled back (i.e. how quickly
and by how much)? That also depends
on the product and some decisions we
made during the sound design process,
as well as what kind of
state-of-emergency your loudspeaker
is in (some people are very mean to
loudspeakers...).
Note that all this is done based on the
signals that the loudspeaker is being
asked to produce. So it doesn’t know
whether you’ve turned up the bass or
the volume – it just knows you’re
asking it to play this signal right now
and what the implications of that
demand are on the current conditions
(voice coil temperature, for example)
This is similar to the fact that the seat
belts in my car don’t know why the car
is stopping quickly – maybe it’s
because I hit the brakes, maybe it’s
because I hit a concrete wall – the seat
belts just lock up when they’re asked
to move too quickly. Your woofer’s
voice coil doesn’t know the difference
between Eminem and Stravinsky with a
bass boost – it just knows it’s hot and it
doesn’t want to get hotter.
19.2
ABL and BeoLab 90
In spite of BeoLab 90’s massive power
reserves and four capable woofers, it
still benefits from the inclusion of ABL
in its processing. This is due to the fact
that the BeoLab 90’s sound design
resulted in a frequency range that
extends to approximately 10 Hz.
Playing at high listening levels, such a
low frequency extension would result
in over-excursion of the woofers if ABL
were not included in the loudspeaker’s
processing. However, it should be said
that whereas a typical Bang & Olufsen
loudspeaker will have an ABL operating
at frequency bands from approximately
100 Hz and down, the BeoLab 90’s ABL
only operates below approximately 20
Hz.
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