SELECTING AN ENCLOSURE
There are several different enclosure designs for different applications.
The REFERENCE subwoofers work
very well
in
all
the following
enclosure designs. it is up to you to select the specific enclosure that will
work the best for your particular application.
Infinite Baffle
Infinite baffle is the simplest type of subwoofer installation. In this type
of installation, the woofer(s) is mounted to a baffle which is then mounted
to either the rear deck or back seat of the vehicle. The best results are
achieved when the trunk area is virtually airtight and isolated from the
passenger compartment.
Pros Cons
@Excellent low frequency extension
l
Lower
power handling
*Excellent transient response L o w to medium efficiency
Uses almost no trunk space
Sealed Enclosure
Sealed enclosures are relatively simple to build and
install, as all that is required is an airtight box. The
larger
the
sealed enclosure, the more the performance
resembles that of an infinite baffle installation. Small
sealed enclosures work very well
in midbass
applications.
Pros Cons
Very good low frequency Medium power
extension handling
Very good transient Medium efficiency
response
Vented Enclosure
Vented enclosures use a sealed enclosure with a vent
or port in the box which is tuned to resonate at a
specific frequency.
Pros
Good low frequency
extension down to the
tuning frequency
High power handling down
to the tuning frequency
Higher output than sealed
enclosures
Cons
Low power handling
below the tuning
frequency
Almost no output
below the tuning
frequency
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Sealed
( S )
-_
:
1
I
ii1- -
Bandpass Enclosure
enclosures
enclose both sides of the
woofer(s). An
airtight
enclosure is built around
the front and back of the
woofer and one or both
chambers are ported to
specific frequencies.
Pros
Sealed
Bandpass (SW)
Cons
Vented Bandpass
High power handling within Low power handling beyond
the operating frequencies the tuning frequency
Very high output within the Poor to moderate transient
range of the operating response
frequencies Poor low frequency extension
Isobaric Woofer Configuration
There are two basic types of woofer
configurations, standard and isobaric. The
standard uses a single woofer
and is the
type used in most subwoofer installations.
There are instances, however, when the
airspace available for
a subwoofer
enclosure is not large enough to
accommodate a particular design. In
these instances, an Isobaric configuration
------
(also known
as
push-pull, compound, clam-shell,
and composite) may work. This configuration
involves two woofers operating as one. The
most common use of the Isobaric configuration
is two woofers bolted together and the polarity is
reversed on one of the woofers so that one
pushes while the other pulls. The benefit of the
Isobaric woofer configuration is that the Vas
(equivalent airspace) of the woofer is halved. By
the same token, the necessary airspace for the
Isobaric Vented Bandpass
Isobaric Sealed Bandpass
(ISOSBP)
woofer to perform in an enclosure is cut in half. The are disadvantages
to the design, however, the main being that even though you are using
two woofers, the output is equal to one woofer in an enclosure twice the
size
of
the enclosure
for the lsobaricly configured woofer.
- CALCULATING (NET) INTERNAL ENCLOSURE VOLUMES -
When constructing any type of enclosure, you must be aware that the
outside dimensions DO NOT represent the true (Net) volume inside.
Such things as woofers, ports, thickness of enclosure material, dividing
wall septums, and any internal bracing will reduce the total amount of the
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