Subwoofer Types
How do subwoofers
affect your Home Theater experience? What is a subwoofer,
anyway?
Subwoofers
are becoming more and more crucial to the home theater experience.
When you go to the movie theater, you marvel not only at
the images projected on the screen, but the sounds emanating
around you. What really grabs you, though, is the sound
you actually feel; the deep bass that shakes you up and
gets you right in the gut.
A specialized
speaker, known as a subwoofer, is responsible for this experience.
The subwoofer is designed only to reproduce the lowest of
audible frequencies.
With
the popularity of home theater sound systems resulting in
specialized speakers for center channel dialogue, main soundtracks,
and surround effects, the need for a speaker to reproduce
just the deep bass portion of a movie soundtrack is all
the more important.
Passive Subwoofers
Passive
subwoofers are powered by an external amplifier, in the
same fashion as other speakers in your system. The important
consideration here is that since extreme bass needs more
power to reproduce low frequency sounds, your amplifier
or receiver needs to be able to output enough power to sustain
bass effects in the subwoofer without draining the amp.
How much power depends on the requirements of the speaker
and the size of the room (and how much bass you can stomach!).
Powered Subwoofers
To solve
the problem of inadequate power or other characteristics
that may be lacking in a receiver or amplifier, powered
subwoofers are self-contained speaker/amplifier configurations
in which the characteristics of the amplifier and sub woofer
are optimally matched.
As a
side benefit, all a powered subwoofer needs is a line output
from an amplifier. This arrangement takes a lot of the power
load away from the amp/receiver and allows the amp/receiver
to power the mid-range and tweeters more easily.
Additional Subwoofer Characteristics
Additional
subwoofer design variations include Front-firing ,
and Down-firing, and the use of Ports or
Passive Radiators.
Front-firing
subwoofers employ a speaker mounted so that it radiates
the sound from the side or front of the subwoofer enclosure.
Down-firing subwoofers employ a speaker that is mounted
so that it radiates downward, towards the floor. In addition,
some enclosures employ an additional port, which forces
out more air, increasing bass response in a more efficient
manner than sealed enclosures. Another type of enclosure
utilizes a Passive Radiator in addition to the speaker,
instead of a port, to increase efficiency and preciseness.
Passive radiators can either be speakers with the voice
coil removed, or a flat diaphragm.