05
Possible Perils Pertaining
To Power Handling
The power-handling capability of
any woofer is related to both its
ability to dissipate heat, and the
maximum excursion limits of its
cone. Power handling for sub-
woofers is directly related to the
type of enclosure that is chosen.
The JBL Power Series sub-
woofers are designed to meet
their power ratings in properly
designed, sealed, vented, and
bandpass boxes. Please be aware
of the following:
• Voice-coil overheating and
burning is typically caused by
overdriving an amplifier into
”clipping“. This damages more
speakers than any other cause.
Damage occurs because the
amplifier is too small rather than
too large. Bass that sounds bro-
ken up and distorted at higher
volumes usually indicates that
the amplifier is being asked to
deliver power beyond its
capabilities.
• Sharp ”popping“ sounds coming
from a woofer indicate that the
voice coil is ”bottoming out“ or
hitting the back of the motor
structure. This can seriously
damage a woofer. Either your
sealed box is too big or leaking
air, the port tuning frequency of
a vented box is too high or your
amp may be overpowering the
woofer. Fix the box, retune the
box or turn the gain down on the
amplifier respectively.
• Infinite Baffle or ”free air“
mounting applications allow for
greater cone excursion than sub-
woofers mounted in an enclosure.
In order to compensate, the
power rating of the subwoofer
should be reduced to half its
rated power. If the woofer
”pops,” turn down the amplifier
gain.
5 Ohms And System
Optimization
In order to increase flexibility,
the Power Series subwoofers are
designed with a 5-ohm nominal
impedance. This provides an
extra margin of safety for simple
installations, and allows those in
competition or those who are
always pushing the ”edge“ to use
more woofers per amplifier chan-
nel safely and efficiently, without
shutting the amplifier down or
exceeding the amplifier‘s SOA
(Safe Operating Area), which
could cause serious damage. In
systems using multiple woofers
per channel, please make sure
your amplifier can drive low-
impedance loads safely and
effectively.
