POLK AUDIO / MOMO DESIGN
54
POLK/MOMO: CHAMPIONSHIP PERFORMANCE
Inverting Phase
Depending on the placement of your custom enclosure and associated components, it may
be necessary to invert the phase of one or another of your system’s connections in order to
gain better subwoofer/mid-range blending. Inverting the phase simply means switching the
positive connections with the negative connections at the amplifier. If you choose to do this,
invert the phase of only one set of speakers (either your mains, or your subs, never both).
Safe Limits Of Operation
Your Polk/MOMO Custom Enclosed Subwoofer is made with the highest quality materials
for years of trouble-free performance. However, damage to loudspeakers can occur when an
amplifier, regardless of its wattage, is made to play at higher listening levels than its power
can clearly produce (usually beyond the “1 to 2 o’clock” position on the volume control).
This results in very high levels of audible distortion, originating in the amplifier, which
adds a harsh, gritty sound to the music. Contrary to popular belief, a speaker is more
likely to be damaged by trying to get too much volume from a low-powered amp than
from a high-powered one. Hear distortion? Turn it down. Contact Polk Customer Service
800-377-7655 (9am—6pm, EST, Monday through Friday).
Low Frequency Cut-Off For Mid-Range Speakers
In Systems With Subwoofers
Now that you have a subwoofer in your system, you may want to decrease the amount
of bass going to your mid-range speakers. This will get you better mid-range sound and
increase the power handling. There are two ways to roll off the bass before it gets to your
mid-range speakers. One way is to use a “bass blocker,” a capacitor placed in series with
the speaker input. Bass blockers are installed in series, one end connected with the positive
lead from your amplifier and the other end connected to the positive lead of each of your
speakers. Bass blocker capacitors (200 microfarad @ 100volts, non-polarized) are available
at any RadioShack or parts supply house. The other route is to use an electronic crossover
device that allows filtering below 100Hz or so. Find these devices at your authorized Polk
Audio dealer.
Permanent mounting is not only the safest installation, but usually produces the best sound
quality. This Custom Enclosure is heavy and has a smooth surface finish, and can slide
around in a trunk during aggressive driving or a collision if unsecured. This could result
in damage to the enclosure or the car.
Use either the mounting brackets provided, or, if you do not wish to drill into your car
body, use a couple of large, well-placed pieces of industrial-strength hook & loop fastener
attached to the enclosure and the trunk surface. Polk Audio takes no responsibility for
damage done to car structures if this product is not secured.
Once you have found the best location, use the enclosed mounting brackets to secure the
subwoofer enclosure to the body of your car. Use the screws included only to attach the
bracket to the subwoofer enclosure. Attach the brackets to the bottom of the enclosure only.
No screws are provided for car-body mounting purposes due to various types of trunk mate-
rials. The installer needs to choose the appropriate screw type and length for the intended
trunk-mounting application. The installer must be careful when drilling into the car struc-
ture not to damage any important elements (fuel lines, electrical conduits, you know; stuff
like that). Polk Audio takes no responsibility for damage done to car structures when
securing this product. If you are at all uncertain about the best and safest way to install
your subwoofer enclosure, consult your local Polk Audio dealer or professional installer.
Break It In
Your Polk/MOMO Custom Enclosed Subwoofer will achieve even greater performance once
it is thoroughly broken-in. To break in your new custom enclosed sub, play 20 to 30 hours
of music at moderate levels. Get more information online at Polk University:
http://www.polkaudio.com/car/faqad/index.php
Amplifier Power Requirements For Polk/MOMO
Custom Enclosed Subwoofers
With one subwoofer we recommend an amplifier with a power rating of at least 200-
Watts (x 1 in bridged mode) to sufficiently drive this woofer. If you have a noisy car or
intend to play your system at loud listening levels, more power is necessary to achieve
the best performance. More power is always better. Consult your Polk Audio dealer for
specific recommendations.
Optimal Crossover Setting
We recommend using an active crossover with a 12 to 18dB per octave low pass filter slope,
and setting it to an initial setting of 80 to 90 Hz as a good starting point. This is an optimal
crossover setting on most vehicles.
