Choosing the Right Woofer/Enclosure System
The purpose of the subwoofer
enclosure is to allow a subwoofer driver to produce the desired bass frequency
response. Not everyone likes the same kind of bass. A 19-year-old hip-hop
fan would want a different kind of sound from a 30-year-old jazz lover.
The keys to getting what you want is understanding the advantages and
disadvantages of each type of box and matching the right box to the right
driver.
Sealed Enclosures
Sealed enclosures will take up less space in the vehicle. Use a subwoofer
driver that is specifically designed for small sealed enclosures like
the Polk dX and Polk/MOMO subwoofers. Sealed enclosures usually produce
a flat, extended and "tight" bass response but are less efficient than
ported enclosures, so you'll need a powerful amplifier to get loud bass.
A sealed box is a good choice for customers looking for an accurate, more
sophisticated sound. It is critical with this kind of design that the
box be well constructed and absolutely airtight. Air leaks will cause
noises that are easily mistaken as blown driver noises.
Ported Enclosures
Ported or "vented" boxes have the advantage of delivering high bass output
with less amplifier power than is needed for a sealed enclosure. Ported
boxes can have very good deep bass response but will be less "tight" sounding
than a sealed box. Vented boxes are larger than a sealed enclosure. At
high volume levels the port can make a "chuffing" noise because of high
speed air-flow in the port tube. Ported systems with high "Vent Air Velocity"
(see
Interpreting Subwoofer Technical Data) are not good choices
for people who want to play their systems very loud.
Bandpass Enclosures
This type of enclosure consists of two enclosure sections. The first section
is a sealed and the second section is ported. The woofer is loaded into
the sealed side and then the front of the cone is firing into the ported
side. This design is called "Bandpass" because it will only reproduce
certain bass frequencies |within a narrow section of the audio band. The
advantages of this type of enclosure are very high efficiency and steeper
filtering of unwanted midrange frequencies. Bandpass boxes can produce
awesome amounts of bass with very little amplifier power. But there is
a price to pay for this efficiency. Bandpass boxes tend to produce "one-note,"
somewhat "boomy" bass and are large. People who like to listen to Bass
CDs tend to like bandpass boxes. They are also a good choice in systems
where another woofer handles the mid-bass chores and the bandpass is needed
only for reproducing the very lowest bass range. Even though they are
ported, bandpass boxes have low Vent Air Velocity and can play very loud
without excessive port noise.
DON'T FORGET!!
To Ensure Good Bass from Your Box:
1. Pre drill all screw holes.
2. Seal all interior seams with a silicone caulking.
3. Install a gasket on the back of the basket.
