Speaker Power Ratings - Rockford Fosgate POWER 650 MOSFET Owner's Manual

high frequency amplifiers of biamplified systems. If the high-
frequency amplifiers are significantly lower in power, the highs
will clip before bass distortion is audible, and much of the bass
power capability will be wasted.
Triamplifying; that is, using another active crossover and stereo
amplifier to run the tweeters only, is technically interesting but
less cost-effective. For one thing, there is little or no masking
effect from the very high frequencies for midrange distortion, so
the biggest performance advantage of multiple-amp systems
isn't available. Crossover components for passive midrange-to-
tweeter crossovers are reasonably small and inexpensive.
Running a separate tweeter amp system will prevent tweeter
burnout due to heavy midrange clipping, and this is the most
substantial advantage

SPEAKER POWER RATINGS

The Power 650 MOSFET is a very high-powered amplifier, and
special care must be taken to be sure that the speakers can
handle the power level. Speaker manufacturers' recommenda-
tions for power levels and crossover frequencies should be
observed. The power capacity required for speakers cor-
responds to the rated output of the amplifier and the mode of
operation. Minimum output into various loads is shown below:
MODE
Stereo
Bridged
Woofers with high power ratings sometimes "pop", "clang",
"snap", or otherwise show signs of bottoming. These speakers
are designed to use the "air spring" of an enclosed box to
prevent bottoming at high power inputs. This applies to most
woofers originally designed for home or professional use. One
solution is to use speakers designed for "infinite baffle" use,
which have very stiff suspensions. The best solution is to build
boxes for the woofers.
As with woofers, midrange drivers' power capabilities are
determined by voice coil and suspension design. The most
common power-handling problems for mid-ranges arise when
they are crossed over at too low a frequency or with too shallow
a crossover slope.
of triamplified systems.
4-Ohm Speaker
125 Watts
325 Watts
For every doubling of the crossover
-7-
8-Ohm Speaker
75 Watts
250 Watts