5
4
Enclosures
Enclosures
Carton Contents
• T2 Subwoofer with Trim Ring
• (12) Mounting Screws
• (4) Trim Ring Screws
• (1) Socket head driver bit
• Installation and Operation Manual
Subwoofer Removal
Due to the size and weight of this subwoofer, it is attached to a wood shipping
baffle to provide additional support during shipment. You must remove the trim
ring to expose the mounting screws attaching the subwoofer to the wood shipping
baffle.
Recommended Enclosures
This manual outlines two specific types of enclosures that provide distinctly dif-
ferent performance. This section is to help you decide which type is best for your
application.
Sealed Enclosures
Sealed enclosures are the simplest to build. The most important part of building
a sealed enclosure is to make sure that the enclosure is airtight. Using glue and
some type of sealant on all seams will ensure solid construction and prevent air
leaks. The box volume will directly impact the performance of the speaker. Larger
enclosures will provide flatter response and deeper bass where smaller boxes will
provide a bump in the response curve and generally higher output for greater SPL.
Advantages of sealed enclosures:
• Small enclosures
• Linear (Flat) response
• No port noise
• High power handling at all frequencies
• Excellent for sound quality
• Extended low frequency output when compared to vented enclosures
Vented Enclosures
Vented enclosures vary only from the sealed enclosure in that a vent or port is
added to “tune” the enclosure. The enclosures recommended are designed for
great overall performance. Larger boxes tend to be easy to tune to lower frequen-
cies while medium and small boxes are easier to tune to higher frequencies. The
vented design is less linear in response than the sealed box but with noticeably
more output at the tuning frequency.
Advantages of vented enclosures:
• Higher average output than sealed
• Tuning frequency can be easily adjusted by changing port length
• Deep bass response with lower power requirements
• Great for high output with limited power
Vented vs Sealed
The graph shown here is a sample of how the F3 drop-off point differs between
sealed and vented enclosures.
Vented Enclosures
NOTE:
Vb is the internal volume, before any speaker and/or port
displacement is added. All external dimensions were based on
the use of 1” (2.54cm) materials.
NOTE:
When using enclosures other than recommended, call Technical Support
for correct application.
Optimum High Output Vented (Ported) Enclosure Sizes
H.O. Vented Enclosures
13”
16”
Total Internal Volume cu. ft. (Liter)
4.0 (113.27)
5.5 (155.74)
V
b
- Internal Volume cu. ft. (Liter)
3.1 (87.78)
4.11 (116.38)
Woofer Displacement cu. ft. (Liter)
0.25 (7.08)
0.29 (8.21)
Port Displacement cu. ft. (Liter)
0.65 (18.41)
1.1 (31.15)
F
B
- Tuning Frequency (Hz)
38.0
35.0
F
3
- 3dB Point (Hz)
32.0
29.0
H - Height - inch (cm)
16.0 (40.64)
20.0 (50.8)
W - Width - inch (cm)
38.0 (96.52)
33.0 (83.82)
D - Depth - inch (cm)
16.0 (40.64)
18.5 (47)
P - Port Area (Height x Width) and Length
- inch (cm)
14 x 3 x 20.5
(35.56x7.62x52.07)
18 x 3 x 23
(45.72x7.62x58.42)
NOTE:
The port shown can be placed on any face of the enclosure as long as the
port ends are not obstructed.
NOTE:
When using vented enclosures, for maximum reliability and power han-
dling ensure, that a subsonic or “infrasonic” filter is used so that only usable low
frequency signal is sent to the subwoofer.
Building an Enclosure
To work properly, the walls of the enclosure must be rigid and not flex when sub-
jected to the high pressures generated by the speaker’s operation. For optimum
performance, we recommend using
1” MDF
(Medium Density Fiberboard) and
internal bracing. The enclosure should be glued together and secured with nails
or screws.
Calculating Volume
Calculating volume is merely a matter of measuring the dimensions in inches and
using the formula: H x W x D divided by 1728 (cubic feet). See block below.
Box Volume
Height” x Width” x Depth”
Divided by (cubic feet)
1728
If two facing sides are of uneven length, add them together and divide by two to
take the average. Using this number will give you the volume without the necessity
of calculating the box in sections and adding the sections together. The thickness
of the baffle material reduces the internal volume so this must be subtracted from
the outside dimensions to determine the internal volume. The speaker itself also
reduces the internal volume. The amount of air displaced by each model is listed
on the specification sheet and should also be subtracted from the gross volume
calculation.
Sealed Enclosures
NOTE:
Vb is the internal volume, before any speaker and/or port
displacement is added. All external dimensions were based on
the use of 1” (2.54cm) materials.
NOTE:
When using enclosures other than recommended, call Technical Support
for correct application.
Optimum Sealed Enclosure Recommendation
Sealed Enclosures
13”
16”
Total Internal Volume cu. ft. (Liter)
1.85 (52.39)
2.40 (67.96)
V
b
- Net Internal Volume cu. ft. (Liter)
1.6 (45.31)
2.11 (59.75)
Woofer Displacement cu. ft. (Liter)
0.25 (7.08)
0.29 (8.21)
F
3
- 3dB Point (Hz)
55.5
43.3
Qtc - Enclosure Damping
0.54
0.74
H - Height - inch (cm)
16.0 (40.64)
20.0 (50.8)
W - Width - inch (cm)
20.0 (50.8)
21.0 (53.34)
D - Depth - inch (cm)
14.5 (36.83)
14.5 (36.83)
Recommended Sealed Enclosure Volume Range
Sealed Enclosures
13”
16”
V
b
- Volume range cu. ft.
(Liter)
1.00 to 2.00
(28.32 to 56.63)
1.5 to 2.5
(42.48 to 70.79)
Wiring Configurations
By varying the wiring configuration of your speakers you can create an impedance
load to match your system. Altering the wiring configurations gives a range of
options for impedance loads. Series, Parallel, or Series-Parallel wiring configura-
tions are different techniques for wiring speakers that provide different loads. Se-
ries configuration is a string method where speakers are wired end to end. Parallel
configuration uses two or more speakers wired across common terminals. Series-
Parallel configuration combines both techniques. Choose the wiring diagram that
corresponds to the number of woofers and the impedance of your amplifier.
Subwoofer Crossovers
There are two operational types of crossovers, passive and active. Passive cross-
overs (coils or inductors) are placed on the speaker leads between the amplifier
and speaker. An active crossover is an electronic filter that separates the audio
signal fed to different amplifiers. For optimum subwoofer performance, we recom-
mend using an active 80-100Hz low-pass crossover at 12dB/octave.
60.0
70.0
80.0
90.0
100.0
110.0
120.0
130.0
10.0
20.0
40.0
60.0
80.0 100.0
200.0
Frequency, Hz
Sealed Box
Vented Box
H
W
D
(2) 2 ohm SVC Speaker = 1 ohm Load
Parallel Wiring
2Ω
2Ω
1Ω
(2) 1 ohm SVC Speaker = 2 ohm Load
Series Wiring
1Ω
1Ω
2Ω
1" MDF
H
W
D
P
