Niles Audio PSW8 User Manual

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I N S T A L L A T I O N & O P E R A T I O N G U I D E




A N D A R C H I T E C T U R E®


Thank you for choosing a Niles loudspeaker. With proper installation and operation, you'll enjoy years of trouble-freeuse.

The PSW8 wall mount subwoofer is uniquely designed to provide unobtrusive low frequency augmentation. The selectable high and low-passfilters 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




























































©2000 Niles Audio Corporation. All rights reserved. Niles, the Niles logo, Blending High Fidelity and Architecture and Systems Integration Amplifiers are registered trademarks of Niles Audio Corporation. BumpBack and MicroSensor are trademarks of Niles Audio Corporation. Dolby is a registered trademark of Dolby Laboratories Licensing Corporation. Decora is a registered trademark of Leviton Manufacturing Co. Because Niles strives to continuously improve its products, Niles reserves the right to change product specifications without notice. The technical and other information contained herein is not intended to set forth all technical and other specifications of Niles products. Additional information can be obtained on-lineat or by calling Niles at1-800-289-4434.Printed in Taiwan. 11/00 DS00278ATW

Features and Benefits

Injection Molded TCC (Talc, Carbon and Ceramic) Woofer with Butyl Rubber

Surround and Vented Pole Piece

The Niles PSW8 Subwoofer employs a newly developed cone material that combines injection molded polypropylene with talc, carbon and ceramic stiffening agents. The result is a cone that offers extreme stiffness and light weight for accurate, dynamic response. Additionally, the woofer employs a vented pole piece for increased bass linearity and a Butyl Rubber Surround for improved damping and clarity as well as moisture resistance.

Figure 1

Model PSW8 Shown

Inverted Dust Cap

The inverted dust cap feature of the PSW8 actually reinforces the cone to further increase the stiffness-to-massratio and reduce distortion. In a subwoofer application, this dust cap inversion offers the additional benefit of reducing the “oil can” effect that can cause traditional woofers to produce unwanted high frequency overtones.

Antiresonant Wave Bracing

The HD speaker’s baffle design employs specially molded ribs that increase the rigidity of the baffle and raise the resonant frequency so that less “out-of-phase”cancellation takes place. Equally important, the ribs are curved and crossed to further shift vibration modes away fromlow-basscanceling frequencies. This keeps bass tones rich and dynamic.

New Construction Wings



Speaker Baffle

IR Knockout


Figure 2

The PSW8 In-wallsubwoofer includes an easy access, baffle mountedhigh-passfilter to preventover-excursionof the satellite’s woofers. It also has an easy access, baffle mountedlow-passfrequency selection switch.

Benefits and Features


Benefits and Features

High Power Handling

The PSW8 employs an exceptionally heavyduty magnet/voice-coil/spiderassembly that is capable of handling high power amplifiers (up to 150 watts).

Infinite Baffle Design

The PSW8 is designed for optimum low frequency reproduction in a traditional 2 x 4 stud wall with varying air volumes. It does not require a special enclosure to provide high performance.

Selectable Low-PassFilter

Installers can select to roll off the high frequencies from the PSW8 at 12dB per octave at either 100Hz or 140Hz. This selection is accomplished via baffle-mountedcontrols that are accessible even after the subwoofer has been installed.

Selectable High-PassFilter

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-passfilter, this selection is accessed via baffle mounted controls.

Moisture Resistant Construction

All components of the PSW8 are moisture resistant. The aluminum grille is rustproof. This makes the subwoofer ideal for moist environments which would cause some brands of speakers to discolor. However, the PSW8 is not waterproof and direct contact with water should be avoided.

Low Diffraction, MicroPerf

Aluminum Grilles

HD speakers include aluminum grilles. The painted aluminum grille has hundreds of precisely sized perforations, creating an acoustically transparent grille.

No-StripSpeaker Terminals

The PSW8 is equipped with both left and right speaker level input terminals to accommodate a stereo amplifier driving a single subwoofer.

Output terminals are also provided to utilize the switchable low-passfilter and provide for convenient wiring to the satellite speakers. All terminals are Niles patentednon-stripdesign, which greatly simplifies installation.

Easy Retrofit Installation in your Existing Home

Designed for ease of installation, the Niles mounting system makes retrofit installations simple and fast. A supplied template assures fast and accurate hole cutting. The bracket slips behind the drywall and the screws secure the bracket to the frame, sandwiching the drywall between them. The speaker baffle attaches to the frame, and the grille mounts over the speaker.

Snap-inBaffle Assembly

This proprietary Niles design enables installers to attach Niles loudspeaker assemblies to previously installed frames without additional hardware or tools. Niles' Snap-indesign makes it easy to upgrade Niles' speakers after installation without the hassles associated with removal and reinstallation of traditional designs.Snap-inbaffles make installation of Niles speakers easier and faster than otherin-wallbrands.

Three Stage Installation System for Remodels or New Construction

You install only the parts you need for a particular stage of construction. When the framing and wiring are finished, you install the bracket. After the drywall is up, but before the painter begins to paint, you install theframe and provide the rustproof aluminumgrilles to the painter so that they can be painted to match the surroundings. Only when construction is completely finished do you put the valuablespeaker in the wall. You don’t have to mask or prep the speaker for painting, and worries about theft during the final phases of construction are never an issue!


How Many Subwoofers?

For most applications a single PSW8’s is appropriate. However, in large rooms, high performance listening rooms or in home theaters, an array of two or more PSW8s 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 PSW8s to install in your home.


Decibels and Power


Conversation at three feet.


Sewing Machine at three feet.


Vacuum Cleaner at 10 feet.


Subway Train entering a station


at 20 feet.


The smallest difference in volume


the human ear can easily detect.


Perceived as twice as much loud-


ness if it is an increase (half as


much if it is a decrease).

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 16’ x 18’ x 8’ Room @ 12’


25 Watts

100 Watts

1 Sub



2 Subs



VLSA of 4 Subs



2 x Watts = 3dB Increase in Volume.

2 x Subs = 3dB Increase in Volume.

2 x Subs = 1/2 the subwoofer excursion for the same volume.

If you double the distance from the subwoofer to the primary listening position you decrease the volume by 4 to 6dB.

Single Stereo Subwoofer

One PSW8 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 settings 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 PSW8 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 PSW8 paralleled. This requires a multi-channelamplifier 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 multi-channelamplifier with one channel assigned to each subwoofer.(See Figure 7).

Subwoofers? Many How




Single Stereo Subwoofer

A four conductor wire (Left+, Left-,Right+ andRight-)16 gauge or larger is run from the amplifier location to the local volume control.(See Figure 4).


Dual Subwoofer Systems

A four conductor wire (Left+, Left-,Right+ andRight-)16 gauge or larger is run from the amplifier location to the local volume control.(See Figure 5).


Left Right




Wire to











Left and Right

Left and Right

Input terminals

Output terminals




Satellite Speaker

Satellite Speaker

Figure 4

A Single PSW8 Hook-Up

From the local volume control, the four conductor cable is run to the PSW8 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 switches can be adjusted.

Satellite Speaker

Satellite Speaker

Figure 5

A Dual PSW8 Hook-Up

From the local volume control, a two conductor cable is run to each of the PSW8s 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 from the left channel output on the left channel subwoofer and fed to the left satellite speaker and another two conductor wire connects from the right channel subwoofer output to the right channel satellite.


Now, the volume control will raise and lower the volume for the subwoofers and the left and right speakers simultaneously. Additionally, the crossovers are now connected so that the crossover switches can be adjusted to your requirements. You must adjust the crossovers on each subwoofer 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 PSW8, giving you a 2dB increase in output. Since each subwoofer’s impedance drops from 8Ω to 4Ω, make sure your amplifier is 2Ω stable to accommodate the satellite speaker’s impedance.(See Figure 6).

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 PSW8 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, inwall 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 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 PSW8 to a multi-channelamplifier like the NilesSI-1230twelve-channelamplifier.

Each PSW8 has a jumper installed to parallel the voice coils for maximum efficiency.

(See Figure 6).

The crossover controls on each subwoofer affect only the subwoofer response. Level controls on the amplifiers facilitate blending and compensation for placement.

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 terminals of the PSW8 speakers will accommodate up to 12 gauge wire. When you run wire inside walls, special jacketing (CL-2orCL-3)is required to both protect the wire and for fire prevention. In some areas conduit is required. For atrouble-freeinstallation, 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.





With One or Two Subwoofers

When one or two PSW8 subwoofers are connected to the satellite speakers, the overall system impedance to the amplifier lowers.

System Impedance in Ohms ()

One or Two Subwoofers




1 Sub



2 Subs @8Ωeach



2 Subs @4Ωeach



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 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.

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, amulti-channelamplifier stable to four ohms is the best way to drive more than two subwoofers. Each PSW8 is connected to its own channel of themulti-channelamplifier.

Check Your Amplifier’s Specs

Every amplifier has a minimum impedance specification. Check your owner’s manual for the specification for four ohm low impedance drive capability. If there is no

clear indication and your amplifier or receiver has two sets of speaker terminals (typically labeled “A” and “B”) your amplifier may be capable of driving a four ohm load. Perform the following test to be sure:

Parallel/Serial Speaker Connection Test

1.Hook up one pair of speakers to the “A” speaker terminals of your amplifier. Leave the “B” terminals unconnected to speakers.

2.Engage both the “A” and the “B”. Listen for sound.

If your amplifier plays sound when “A” and “B” are engaged, it is capable of driving a four ohm speaker load. If your amplifier does not play sound when “A” and “B” are selected, it is only capable of driving an eight ohm speaker load. An eight ohm stable amplifier may only be used with a PSW8 satellite/subwoofer system by installing an impedance magnifying volume control.

An amplifier stable to four ohms may be connected without impedance matching devices. Parallel connections via the “A” speaker terminals to one or two PSW8 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 anymore. The low impedance drive capability 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.


Using Speaker Selectors With

Standard Volume Controls

In multi-roomsystems with standard volume controlsany Niles speaker selector will maintain a four ohm load if you leave one set of room outputs unused for every speaker system with an impedance of less than four ohms (such as a PSW8 connected to a pair of four ohm satellite speakers). The protection switch must be constantly engaged. Niles HDL series speaker selectors have a rear panel constant protection feature.(See Figure 8).

The benefit of a speaker selector is that even with the protection circuit constantly engaged, more power will be delivered to any single pair of speakers playing by itself (all other speakers off).

In a multi-roomsystem there is one indispensible control for trueconvenience—alocal volume control. It allows you to adjust the volume of the speakers and the subwoofer without leaving the room.

Niles makes a wide range of high performance indoor and outdoor volume controls in Standard or Decora® style face plates (just like your light switches and dimmers). All of these volume controls enable full power to be delivered to each speaker system when turned all the way up.

The combination of a speaker selector and a standard volume control will deliver high volume when only one pair of speakers is playing.

Figure 8

Setting the constant protection switch on the Rear Panel of a Niles HDL series speaker selection system.

Using Impedance Magnifying

Volume Controls

The simplest way to increase the impedance of a satellite/subwoofer system is to install a Niles VCS-2D-IMorVCS-2S-IMimpedance magnifying volume control instead of a standard volume control. This control has a behind the wall jumper which is set at the time of installation to “magnify” the speaker system’s impedance.

(See Figure 9).













































































































Figure 9

Setting the jumper on the Niles VCS-2D-IMorVCS-2S-IMImpedance Magnifying Volume Control

For example: In the two times position, an IM volume control will enable an eight ohm stable amplifier to play a 4 ohm speaker system without overheating. The available power will decrease, which you will perceive as a 3dB drop in maximum undistorted volume.

If the jumper is set to the 4x position, a 6dB drop in volume will be perceived.

If the jumper is set to the 8x position, a 9dB drop in volume will be perceived.

A 10dB drop is perceived as half as loud, so there are limits to the amount of magnification you can use unless the amplifier is very powerful (3dB increase every time you double the power) or you never listen at high volumes. Consult the Decibels and Power chart on page 4.



Placement & Treatment

Treatment & Placement

Typically, sheetrock encloses the subwoofer in most installations. Sheetrock has a fairly loud resonant “twang” compared to the rigid non-resonantenclosures of most floor standing subwoofers. None of the following modifications are absolutely necessary, however any one or combination of them will improve the performance of the subwoofer.

Minimum Enclosure Size

The PSW8 will produce magnificent results if the wall cavity behind the woofer is a minimum of 1900 cubic inches. If the wall studs center measure 4” deep (2x4) and are spaced 14-1/4”apart (16” spacing) you would want the length of the air cavity to be a minimum of 33- 1/3”. A larger cavity is fine.


Lay a batten of fiberglass insulation (e.g. R-19un-battedinsulation) behind of the speaker. If you have more than one subwoofer in the room, place the same amount of insulation behind each subwoofer. If your enclosure is smaller than the recommended 1900 cubic inches, try packing more insulation into the space behind the speaker. This effectively increases the enclosure size.

Enclosure Bracing

Insert small pieces of 1x2 or 1x1 scrap wood as wedges between the front and back panels of sheetrock if possible. Do not use too long of a piece as you could create a bulge in the wall surface.

Enclosure Lining

Purchase some subwoofer damping material from a car stereo store (there are various brands available, e.g. Dynamat). Apply the damping material to the back of the wall behind the PSW8 and to the sheetrock surrounding the wall beside the subwoofer.

Speaker Placement Techniques

Although the PSW8 has extensive ability to compensate for unusual placements with its crossover switches; placement is still the primary tool for satisfying your particular listening needs.

Maximizing Output

The Boundary Effect – Placing your subwoofer near the floor or in a corner will increase the volume of bass sound produced by the subwoofer! This is called the boundary effect. Generally, you can expect a 3dB increase in sound pressure level by harnessing the boundary effect.

Proximity – Place the subwoofer as close as possible to the primary listening position. Sound dissipates indoors at approximately 4dB to 6dB for each time you double the distance from the subwoofer to the listener. Therefore you can expect a 4dB to 6dB increase in output every time you halve the distance from the subwoofer to the listener.

Improving the Stereo Image

Place the subwoofer(s) as close as possible to the satellite speakers.