SPL
170
Subwoofer
OWNER'S MANUAL AND
INSTALLATION GUIDE
SOUNDSTREAM TECHNOLOGIES
120 Blue Ravine Road · Folsom · California 95630 USA
tel 916.351.1288 fax 916.351.0414
(REV A, 7/22/97)
Vented (Continued)
· 4.5 ft3 @ 25 Hz (Two
105
100
95
90
85
80
75
70
65
60
55
50
HEAT TRANSFER AND THE
SPL170 -- 30 % BETTER COOLING
4"
x
16" ports)
-
D e s i g n e d
thunderous
f o r
home
One of the major features of the SPL170 is its incorporation of materials and coatings to
provide transfer and elimination of heat.
theater bass. Use with
20 Hz high pass filter
for very high power
handling.
10
100
1000
·
·
When heat is produced in the voice coil, it must be removed. During speaker operation,
heat from the voice coil is radiated and convected into the air and metal in the motor
parts.
Frequency Hz
Vented (V)
The SPL170 includes unique aluminum plates attached to the top, pole and back plates
to increase heat conduction from the steel parts. Additionally, the steel parts are black
coated to increase their ability to absorb heat from the voice coil.
Sealed Bandpass
105
100
95
90
85
80
75
70
65
60
55
50
·
·
Rear = .87 ft3 sealed
Front = 1.5 ft3 @ 75
ALUMINUM
COOLING
PLATES
Hz
(Five 4" x 10"
ports)
o u t p u t
-
Very high
i n tiny
10
100
1000
Frequency Hz
enclosure. Great for
SPL vehicles -- 102
dB with 2.83 volts
Sealed
Bandpass
(SBP)
105
100
95
90
85
80
75
70
65
60
55
50
input!
Response
limited to 45 to 100
Hz.
·
·
Rear = 1.2 ft3 sealed
Tests show almost 30% improved heat transfer from the 170’s voice coil. This produces a
dual benefit to power handling and output:
Front = 1.5 ft3 @ 62
Hz (Three 4" x 10"
ports) - High output
with response to 35
Hz. Good enclosure
for Rock and Rap
music. 100 dB with
2.83 volts input.
10
100
1000
Frequency Hz
1. More power handling before voice coil meltdown.
2. Reduced electrical resistance in the voice coil windings resulting in more current flow
capability.
105
100
95
90
85
80
75
70
65
60
55
50
Footnote: The Physics of Heat Transfer
·
·
Rear = 2 ft3 sealed
Front = 1.5 ft3 @ 53
10
100
1000
Frequency Hz
Heat energy, q, radiated between two bodies is determined by the formula:
q1-2 = s eA1F1-2(T14-T24)
SPECIAL APPLICATION NOTE:
The three enclosures above have been designed with flexibility in mind. One
single enclosure could be constructed to utilize all three response curves. An
adjustable rear volume and port "covers" could allow use of all three
An important part of this equation is e which is the “emissivity”. The larger e is, the more heat
transfer takes place. e is largest for a black surface (1.0). That’s why wood stoves and car
radiators are painted black.
10
3
SPECIFICATIONS & THIELE/SMALL PARAMETERS
SUGGESTED ENCLOSURES
Infinite Baffle
25-500
96 dB
2/8
Frequency Response (Hz)
Sensitivity (2.83v/1m)
Impedance (nominal Z, ohms)
Rated Program Power, Watts
Fs (Hz)
· Excellent performance for all types of music at moderate levels
100
Sealed
95
800
· 1.0 ft3 - Great all
90
85
80
around performing
26.2
.371
7.43
.390
67.1
6.36
180
75
70
box. Very small
enclosure. Good for
Rock and Rap.
65
Qts
60
55
50
Qms
10
100
1000
Frequency Hz
Qes
Sealed
· 2.0 ft3 - Slightly deeper
response. Strong
bass at 20 Hz in car.
Good for Rock, Rap
and Jazz.
100
95
90
85
80
75
70
65
60
55
50
Efficiency Bandwidth Product (Fs/Qes)
Vas (ft3)
Vas (liters)
Vas (m3)
.180
160
10
100
1000
Frequency Hz
Cms (um/N)
2.24
2.475
14.75
131.0
.089
890
DCR (ohms)
Levc (mH) @ 1 KHz
105
100
95
90
85
80
75
70
65
60
55
50
BL (Tesla m)
Vented
Sd (in2)
· 2.0 ft3 @ 40 Hz (Two
4" x 13.5" ports) - Very
strong output from 40
Hz to 100 Hz.
Sd (m2)
Sd (cm2)
10
100
1000
Suggest using high
pass filter near 40 Hz
for maximum power
handling and output.
Very small enclosure.
9.5
X max; one way (linear mm)
X max; one way (peak mm)
Vd (linear cm3)
Frequency Hz
Vented (V)
27
847
105
100
95
90
85
80
75
70
65
60
55
50
· 3.2 ft3 @ 28 Hz (Two
4" x 18.5" ports) - Very
strong output to 30 Hz.
Good for home theater
or accurate bass in
Vd (peak cm3)
2403
0.000847
0.002403
230
Vd (linear m3)
Vd (peak m3)
10
100
1000
Mms (grams)
Frequency Hz
358
Magnet Assembly (oz)
118
Magnet Weight (oz)
9
3
385
BUILDING THE ENCLOSURE
SELECTING AN ENCLOSURE
There are several different enclosure designs for different applications.
The SPL 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.
· Determine the dimensions of your enclosure.
· Be certain the box you have designed will fit into the location you have
chosen. Sometimes making a cardboard box with the same outside
dimensions is helpful.
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.
· Use 3/4 inch thick Medium Density Fiberboard (MDF) or High Density
Particleboard. It is preferable to cut the wood with a table saw to ensure
straight, even joints. If a table saw is not available, a circular saw is
acceptable.
· Use a “T” square to verify precise right angle gluing.
Pros
Cons
· Use a high quality wood glue and air nails or wood screws to assemble the
enclosure. Elmer’sâ woodworker’s glue and Weldwoodâ work well. To
guarantee an airtight box, seal each inside joint with silicone sealant.
· Excellent low frequency extension
· Excellent transient response
· Uses almost no trunk space
· Lower power handling
· Low to medium efficiency
· For Sealed Enclosures, stuff the chamber with 50-75% filling (approximately
1.5 pounds per cubic foot) of fiberglass insulation or Dacronâ .
Sealed Enclosure
· For Vented Enclosures, staple 1 inch thick fiberglass insulation or Dacron to
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.
all walls of the enclosure except the baffle to which the woofer is mounted.
· Use the supplied gasket to seal the woofer in the enclosure and eight(8)
wood screws or T-nuts and bolts. Progressively tighten each of the bolts or
screws to prevent warping the woofer frame.
Pros
Cons
· Very good low frequency
extension
· Medium efficiency
· Use slide-on connectors to attach speaker wires. Do not solder wires to the
· Very good transient re-
sponse
· High power handling
SUGGESTED ENCLOSURES
The following designs include a variety of enclosure sizes and types.
Each design has two frequency response curves; one showing predicted
“In-Car” response, and the other showing “Half-Space Anechoic” (out-of-car)
frequency response. The performance difference between the two curves is a
result of the natural acoustics of an “average” automotive environment. This
“average” transfer function is only an approximation of what you may expect to
see in your car. Every car is different. Each curve was generated using 2.83
Volts across both voice coils in parallel and measured at 1 meter. Also, each
frequency response curve includes a 12 dB/octave low pass at 100 Hz for
sealed and vented enclosures and 200 Hz for bandpass enclosures. The
response curves can help you visualize relative performance differences
between designs. Read through the descriptions given for each enclosure and
select the one that suits your needs.
Sealed
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
Cons
· Good low frequency exten- · Low power handling
sion down to the tuning fre-
quency
below the tuning fre-
quency
· High power handling down · Almost no output
to the tuning frequency
· Higher output than sealed
enclosures
below the tuning fre-
quency
Remember: all suggested enclosure volumes are Net, and DO NOT include
woofer, port, and bracing displacement!
Vented (V)
8
5
ENCLOSURE VOLUME FLOWCHART
Sealed Bandpass Enclosure
Sealed bandpass enclosures enclose both sides of the woofer(s). An
airtight enclosure is built around the front and back of the woofer and
one chamber is ported to a specific frequency.
Measure maximum possible dimensions
Pros
Cons
Multiply wall thickness by 2
· High power handling
within the operating
frequencies
· Low power handling
beyond the tuning
frequency
· Very high output within · Poor to moderate
the range of the oper-
ating frequencies
transient response
· Poor low frequency
extension
Subtract this from each dimension to
arrive at Gross Internal Dimensions
Sealed
Bandpass
(SBP)
Multiply LxWxD to arrive at
Gross Internal Volume
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
walls, and any internal bracing will reduce the total amount of the
actual air space available. The following worksheet has been designed
to provide you with the necessary steps to accurately calculate the
absolute (Net) internal volume of any given enclosure.
Deduct Vf (volume of the speaker frame)
from Gross Internal Volume
Braces?
Calculating Cylindrical Port Volume
No
Yes
1. Measure the outside diameter of the port and divide by 2 for the
radius.
2. Square the radius and multiply by 3.14 (p) to arrive at outside port
Calculate brace volume and deduct
from Gross Internal Volume
area.
3. Multiply the area by the length of the port inside the enclosure for
To convert to LITERS:
Divide in3 by 61.03
the port volume.
You are at Net Internal Volume
in cubic inches (in3 )
To convert to CUBIC FEET:
Divide in3 by 1728
length inside
enclosure
outside
diameter
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