Niles Audio CM8SW User Manual
INSTALLATION & OPERATION GUIDE
INSTALLATION & OPERATION GUIDE
CM8SW
SUBWOOFER
B LENDING H IGH F IDELITY
AND A RCHITECTURE
®
®
Congratulations!
Thank you for choosing a Niles ceiling mount loudspeaker. With proper installation and
operation, you'll enjoy years of trouble-free use.
The CM8SW is a ceiling mount subwoofer uniquely designed to provide unobtrusive
low frequency augmentation. The selectable high and low-pass filters make it suitable for
use with a wide variety of satellite speakers.
Niles manufactures the industry's most complete line of custom installation components
and accessories for audio/video systems. For a free full line catalog write: Niles, Catalog
Request, P.O. Box 160818, Miami, Florida 33116-0818
TABLE OF CONTENTS
FEATURES AND BENEFITS 2
HOW MANY SUBWOOFERS? 4
CONNECTIONS 5
IMPEDANCE 7
TREATMENT & PLACEMENT 9
INSTALLATION FUNDAMENTALS 10
INSTALLATION IN NEW CONSTRUCTION 14
INSTALLATION IN EXISTING CONSTRUCTION 15
FINAL INSTALLATION IN NEW OR EXISTING CONSTRUCTION 16
OPERATION 18
SPECIFICATIONS 19
WARRANTY REGISTRATION CARD 21
LIMITED WARRANTY 22
Features and Benefits
Features and Benefits
TCC Speaker Cone
The Niles CM8SW is a high-performance
passive subwoofer that compliments the
entire Niles ceiling mount loudspeaker
line. It’s dual voice-coil injection molded
TCC (talc, carbon and ceramic) woofer
provides outstanding bass response
The illustration below shows how
a typical Niles CM loudspeaker
mounts into a ceiling.
Knockout wire tie allows
the wire to be secured to
the bracket throughout the
new construction process.
It knocks out cleanly when
the speaker is installed.
New construction
wings instantly snap
into the bracket
without screws.
New Construction Bracket serves as
a “hole saver” when drywall has not
been applied. It is not necessary when
retrofitting to existing ceilings.
High-Power Handling
The CM8SW employs an exceptionally
heavy-duty magnet/voice-coil/spider
assembly that is capable of handling high
power amplifiers (up to 150 watts).
Figure 1
Model CM8SW Shown
Dogs swivel 9
clamp the speaker
frame to the drywall.
Frames are molded with
a slight texture to assure
good paint adhesion.
0°, then
Wings are scored for
easy size trimming.
Brackets and wings
attach to the ceiling joists
with nails or screws.
Figure 2 Figure 3
SAT
FULL
The CM8SW ceiling mount subwoofer includes an
easy access, baffle mounted high pass filter to
prevent over-excursion of the satellite’s woofers.
CUT
The CM8SW ceiling mount subwoofer includes
an easy access, baffle mounted low pass frequency selection switch.
Mounting screws tighten
the “Dogs”, clamping the
speaker to the drywall
Rust-proof aluminum Grilles make the
CM8SW series perfect for moist
environments.
SUB
00Hz
1
140Hz
2
Features and Benefits
Infinite Baffle Design
The CM8SW is designed for optimum low
frequency reproduction in traditional ceiling environments and varying air volumes.
It does not require a special enclosure to
provide high performance.
Selectable High-Pass Filter
Installers can also select whether or not to
filter the low frequencies from the satellite
speakers at a fixed frequency of 120Hz.
Like the low-pass filter, this selection is
accessed via baffle mounted controls
(See Figure 2).
Adjustable Low Pass Filter
Installers can select passive crossover for
both woofer and satellite speakers via
baffle-mounted controls that are
accessible even after the subwoofer has
been installed (See Figure 3).
Weather-Resistant Construction
All components of the CM8SW are weather resistant. The aluminum grille and stainless steel mounting screws are rustproof.
This makes the subwoofer ideal for moist
environments which would cause some
brands of speakers to discolor. Protected
outdoor installations are perfectly suited
for the CM8SW.
MicroPerf™Grilles
The CM8SW employs Niles’ exclusive
MicroPerf grille construction. The exceptionally tight hole pattern provides
acoustic transparency at all audio frequencies and enables the woofer element to
remain invisible. MicroPerf grilles can be
painted to blend seamlessly with the
surrounding decor.
No-Strip Speaker Wire Terminals
Dual Niles patented gold-plated no-strip
speaker wire terminal connectors accom-
8 gauge wire.
modates 12-
1
Easy Installation
The CM8SW employs a bracketless
mounting system for existing ceilings.
Simply cut a hole in the mounting surface,
remove the grille from the subwoofer,
connect the wires and place the speaker
in the hole. Then tighten the four mounting “dogs” via the front panel screws. The
dogs first swivel 90°, then clamp the frame
to the drywall as the screws are tightened.
Hole Saving Bracket
Available as an optional accessory, the
CM8 New Construction Bracket can be
installed as a “hole-saver” before the drywall goes up. The drywall contractor cuts
the hole as the drywall is installed, reducing installation time and minimizing the
chances for lost wires.
3
How Many Subwoofers?
For most applications a single CM8SW is
appropriate. However, in large rooms, high
performance listening rooms or in home
theaters, an array of two or more CM8SW
will deliver astounding results. Unlike
other subwoofer systems, a Niles
Subwoofer Array is concealed. Consider
the distance between the subwoofer(s) and
the listener, the size of the amplifier and
the desired quality and volume of sound
when deciding how many CM8SWs to
install in your home.
Decibels and Power
65dB Conversation at three feet.
75dB Sewing Machine at three feet.
85dB Vacuum Cleaner at 10 feet.
95dB Subway Train entering a station
3dB The smallest difference of sound
10dB Perceived as twice as much loud-
Any speaker requires twice as much
amplifier power to increase 3dB and ten
times as much power to increase 10dB.
Comparison of 1, 2 or 4 Subwoofers
1 Sub 95dB 101dB
2 Subs 100dB 106dB
VLSA of 4 Subs 103dB 109dB
2 x Watts = 3dB Increase in Volume.
2 x Subs = 3dB Increase in Volume.
2 x Subs = 1/2 the subwoofer excursion for
If you double the distance from the subwoofer to the primary listening position
you decrease the volume by 4 to 6dB.
at 20 feet.
the human ear can easily detect.
ness if it is an increase (half as
much if it is a decrease).
16’ x 18’ x 8’ Room @ 12’
25 Watts 100
the same volume.
Watts
How Many Subwoofers?
Single Stereo Subwoofer
One CM8SW can produce the bass sound
from both the left and the right channels
because of its unique dual voice coil
design. One voice coil powers the left channel and the other powers the right channel.
A stereo crossover divides the signal and filters it according to the position of the
switches on the front panel. A single stereo
subwoofer is compatible with any 4 ohm
stable amplifier. Eight ohm stable amplifiers
may be used with a Niles IM volume control (see Impedance section on Page 7)
Dual Subwoofer Systems
Using two CM8SW subwoofers in a system
raises the maximum attainable volume of
the system by 3dB. Additionally, at lower
volumes, excursion — and therefore distortion levels — are reduced. In a large room,
or a home theater system, the effect on
bass quality is extremely desirable.
Another 2dB increase is possible if the
voice coils of each are CM8SW paralleled.
This requires a multi-channel amplifier or
an amplifier capable of driving the 2 to 2.6
ohm load of the overall system.
VLSA Installations
A Very Large Subwoofer Array (VLSA)
installation lowers the amount of excursion
required to achieve a high sound pressure
level. Lowering excursion dramatically
improves the quality of the sound. VLSA
installations are most appropriate when the
listener appreciates detail and bass extension, but must have a concealed installation. A VLSA of four subwoofers must have
a multichannel amplifier with one channel
assigned to each subwoofer.
4
Connections
Left Right
CM8SW CM8SW
Wire to
Corresponding
Output
E
ither Input okay
Satellite Speaker
Amplier
Satellite Speaker
Left Right
CM8SW
Amplier
Left and Right
No-Strip wire input terminals
Left and Right
No-Strip wire output terminals
Satellite SpeakerSatellite Speaker
Connections
Dual Subwoofer Systems
A four conductor (Left+, Left-, Right+ and
Right-) wire 16 gauge or larger (see side-
Single Stereo Subwoofer
A four conductor (Left+, Left-, Right+ and
Right-) wire 16 gauge or larger (see side-
bar on speaker wire gauge) is run from
the amplifier location to the local volume
(See Figure 5).
control
bar on speaker wire gauge) is run from the
amplifier location to the local volume
control (See Figure 4).
Figure 4
A Single CM8SW Hook-Up
From the local volume control the four
conductor cable is run to the CM8SW and
connected to the Input connectors. A two
conductor wire is connected to each of the
stereo outputs and fed to the left and right
speakers. Now, the volume control will
raise and lower the volume for the subwoofer and the left and right speakers
simultaneously. Additionally, the crossover
is now connected so that the crossover
5
switches can be adjusted.
Figure 5
A Dual CM8SW Hook-Up
From the local volume control a two conductor cable is run to each of the CM8SWs
and connected to either the left or the right
Input connectors.
Each of the satellite speakers must be connected to the correct subwoofer. Typically,
a two conductor wire is connected to one
of the outputs on the left channel subwoofer and fed to the left satellite speaker
and another two conductor wire connects
the right channel subwoofer and satellite.
Now, the volume control will raise and
lower the volume for the subwoofer and
the left and right speakers simultaneously.
WR+
W
R–
L–IN R–IN
CM8SW
L
L
C
C
H
H
Additionally, the crossovers are now connected so that the crossover switches can
be adjusted to your requirements. You must
adjust the crossovers on each speaker with
this hook-up.
Optionally, a jumper of wire may be
connected between the L+ and the R+;
and between the L- and the R-. This connects both voice coils of the CM8SW,
giving you a 2dB increase in output.
Since each subwoofer’s impedance
drops from 8
amplifier is 2
the satellite speaker’s impedance.
Figure 6)
Ω to 4Ω, make sure your
Ω stable to accommodate
(See
.
crossover) by a separate amplifier channel.
Connections are straight-forward; two
conductor wires connect each amplifier
channel to each individual subwoofer.
(See Figure 7).
Figure 7
Connections to a VLSA are normally made from
each CM8SW to a multi-channel amplifier like
the Niles SI-1230 twelve channel amplifier.
Each CM8SW has a jumper installed to
parallel the voice coils for maximum effi-
(See Figure 6).
ciency.
The crossover controls on each subwoofer
affect only the subwoofer response. Level
controls on the amplifiers facilitate blending and compensation for placement.
Connections
Figure 6
Connecting the two voice coils in parallel with a
jumper (a piece of speaker wire).
Very Large Subwoofer Array
(VLSA)
Using four or more CM8SW subwoofers
in a system creates a system of unprecedented clarity, with stunning bass impact
and potentially extraordinary maximum
volume capability. Because of the
extremely low impedance of a parallel
VLSA system, multiple channel amplifiers
are normally used to power them.
Because of this, in-wall volume controls
are incompatible with VLSA systems.
In a system of this type, it is recommended
that the satellite speakers be driven full
range (or with an external electronic
Speaker Wire
For most applications, we recommend you
use 16 or 18 gauge wire. For wiring runs
longer than 80 feet we recommend 14
gauge wire. The No-Strip speaker wire terminals can accommodate 12-20 gauge
wire. When you run wire inside walls, spe
cial jacketing (CL-2 or CL-3) is required to
both protect the wire and for fire prevention. In some areas conduit is required. For
a trouble-free installation, low voltage wire
such as speaker wire must be run in accordance with the National Electrical Code
and any applicable provisions of the local
building code. Consult your local Niles
dealer or your building contractor if you are
unsure of code requirements in your area.
-
6
Impedance
Impedance
With One or Two Subwoofers
When one or two CM8SW subwoofers are
connected to the satellite speakers, the
overall system impedance to the amplifier
lowers.
System Impedance in Ohms (Ω)
One or Two Subwoofers
8
Ω Sats 4Ω Sats
1 Sub 4
2 Subs @8Ω each 4Ω 2.6Ω
2 Subs @4Ω each 2.6Ω 2Ω
If the impedance is too low for your amplifier utilize a Niles speaker selector or IM
volume control to match the impedance.
VLSA (Four or More Subwoofers)
A VLSA (Very Large Subwoofer Array)
installation lowers the amount of excursion required to achieve a high sound
pressure level. Lowering excursion dramatically improves the quality of the
sound. VLSA installations are most appropriate when the listener appreciates detail
and bass extension, but must have a con
cealed installation.
Each subwoofer should have its voice coils
connected in parallel for full output, therefore the impedance of each is four ohms.
Because of this low impedance, a multichannel amplifier stable to 4 ohms is the
best way to drive more than two subwoofers. Each CM8SW is connected to its
own channel of a multi-channel amplifier.
Ω 2.6Ω
specification may also be noted on the rear
panel of the amplifier. If your amplifier is
not able to drive a four ohm load it may
only be used to power a CM8SW
satellite/subwoofer system when an impedance magnifying volume control is incorporated into the system
An amplifier stable to four ohms may be
connected without impedance matching
devices. Parallel connections via the “A”
speaker terminals to one or two CM8SW
subwoofers (If the voice coils are not in parallel) and one pair of eight ohm satellite
speakers results in a four ohm load.
The “B” speaker terminals cannot be used
to power a second pair of speakers any-
The low impedance drive capability
more.
of your amplifier is already utilized by the
satellite/subwoofer combination. If you are
connecting other speakers in other rooms
you must install either a speaker selector or
impedance magnifying volume controls.
A few professional/audiophile amplifiers
advertise the capability of driving two
ohm speaker loads. These amplifiers may
be used without impedance matching
devices if the rating is quoted as “RMS” or
“Continuous” power and the amp does
not push too much power.
-
Check Your Amplifier’s Specs
Every amplifier has a minimum impedance
specifications. Check your owner’s manual
to determine whether or not your amplifier
is capable of driving a four ohm load. This
7
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