Niles Audio OS7.5 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





Indoor/Outdoor Loudspeakers


A N D A R C H I T E C T U R E®


Thank you for choosing Niles OS Indoor/Outdoor loudspeakers. With proper installation and operation, you’ll enjoy years of trouble-freeuse.

Niles manufactures the industry’s most complete line of custom installation components and accessories for audio/video systems. To learn more about Niles products, visit our website: or call us at800-BUY-HIFI (800-289-4434).













































Niles once again raises the bar. With our first OS Indoor/Outdoor models we revealed a radical new understanding of loudspeaker capabilities. Niles original OS Indoor/Outdoor loudspeakers are constantly praised for their ability to deliver exemplary reliability and outstanding sound quality. These attributes have made Niles OS Indoor/Outdoor loudspeakers the best selling loudspeakers in their class.

The goal of our new OS Indoor/Outdoor line-upis to raise this bar with refined appearance and superior sonic performance. Once again establishing a benchmark by which all others are judged. The new Niles OS Indoor/Outdoor loudspeakers owe much of their performance and sound quality advantage to design elements pioneered in theaward-winningNiles DS Directed Soundfield™ loudspeakers. Their engineering advances come from our integrated approach to driver and cabinet design. By integrating the woofer basket into the baffle of the cabinet we are able to increase the woofercone-areatocabinet-widthratio. Thus enabling OS Indoor/Outdoor loudspeakers to provide levels of bass performance that substantially exceed their physical size. However, deeper and more powerful bass isn’t the only refinement in the new OS Indoor/Outdoorline-up.A new and modern style enables OS Indoor/Outdoor loudspeakers to blend seamlessly with the architectural elements both indoors and out. After the installation is complete, you will be astonished by the experience of hearing such clean and powerful sound coming from such elegant appearing loudspeakers.





Patent Pending Integrated Woofer/Baffle Assembly

Increases the woofer cone-areatocabinet-widthratio for enhanced bass output

Interlaced Carbon Fiber Woofer Cone

Reduces breakup and lowers distortion

Butyl Rubber Woofer Cone Surround

Damps resonance and provides exceptional durability

Dispersion Stabilizer

Distributes midrange tones for clear off-axissound

Tri-laminateTeteron Dome Tweeter

1" fluid-cooledtweeter providesultra-widedispersion for clear, detailed and extendedhigh-frequencies

Weatherproof Engineering

Enables OS loudspeakers to handle extreme hot, cold and moist environments, exceeding the military’s strict anti-corrosionspecificationMIL-STD-883D

Advanced Material Science

Elevates appearance and longevity of the cabinet and grille, plus enhances the performance of the woofers, tweeters and crossovers

Architectural Friendly Design

Delivers stellar acoustical performance yet tucks discretely away into corners and under eaves


Low Diffraction Grille and Front Baffle

Ensures that the sound waves emanating from the woofer and tweeter are not reflected by the surrounding parts of the loudspeaker for precise imaging and acoustical accuracy

Rigid, Acoustically Inert Cabinet

Prevents transmission of unwanted vibrations for clean and dynamic bass response


Reduces installation limitations to provide great sound from the beaches of Miami to the harsh winters of Minneapolis

Home Theater Applicability

Enables OS loudspeakers to be used as left, center, right, or surround loudspeakers in home theater systems

Integrated Mounting Bracket and Shelf Stand

Provide a variety of secure, quick and easy mounting solutions

Tapered Shape

Facilitates mounting in corners and under eaves

Inverted Gold Plated 5-WayBinding Posts

Repel moisture and ensure positive connections in virtually any conditions over long periods of time











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Figure 1 OS .5 Parts Guide



Mounting Bracket




Nail Hole




Wire Hole


Binding Posts


Screw Hole


Threaded Insert (1/4"-20Thread


Bracket Knob


Shelf Stand

NOTE: Bracket and Shelf Stand are used depending upon installation requirements. See Installation Instructions.




Tools and Materials Required

A wire stripper

A pencil

A level (optional)

Three screws or bolts suitable for the mounting surface

The proper screwdriver for your mounting hardware

A drill bit of the right size and type

An electric drill


The OS loudspeakers connect to your receiver or amplifier using 2-conductorloudspeaker wire (See Figure 2). For most applications, we recommend using 16 or 18 gauge wire. For wiring runs longer than 80 feet, we recommend 14 gauge wire. The binding posts on OS loudspeakers accommodate up to 12 gauge wire directly. Larger sizes can be accommodated using spade, banana, or pin connectors.


Wire size is expressed by its AWG (American Wire Gauge) number. The lower the number, the larger the wire, i.e. twelve AWG is physically larger than fourteen AWG.

When you run wire inside walls, outdoors or in marine installations, special jacketing or conduit is required for a trouble-freeinstallation and conformation to the local and national building codes. If you are not sure of the correct wire jacket or type of conduit to use, consult a professional audio/video installer, building contractor, or the local building and inspection department.

Incorporating a Volume Control

It’s possible to control the volume of the sound at the loudspeaker location. Plan to wire the system so that each pair of loudspeakers has its own volume control. Niles makes a wide range of indoor and outdoor volume controls with and without muting capabilities. Consult your local Niles dealer for more information. Volume controls are connected in line with the loudspeaker, so you must connect the wire from the amplifier to the volume control and then from the volume control to the loudspeaker (See Figure 3).



Figure 2

Figure 3

Wiring directly from a receiver

Incorporating a volume control

or amplifier


Recommended Amplifier Power

For optimum performance, we recommend an amplifier with a power rating of: five

(5) to one hundred (100) watts per channel for the 0S 5.5 loudspeaker; five (5) to one hundred twenty five (125) watts per channel for the OS 6.5 loudspeaker; five

(5) to one hundred fifty (150) watts per channel for the OS 7.5 loudspeaker. Ironically, most loudspeakers are not damaged by large amplifiers but by small amplifiers. If you are playing at high volume, a small amplifier will run out of power very quickly. When an amplifier runs out of power it creates damaging “clipping” distortion. A large amplifier will play at the same volume without distorting. See the section “Operation” for more information about clipping distortion.

Placing Loudspeakers for the Best Sound Quality

An OS loudspeaker’s dispersion pattern is very broad. This allows good sound quality over an extremely large listening area. However, if a single pair is positioned to provide coverage of a very large room or patio, you will have “hot spots” of loud sound when you are near the loudspeakers. The best way to avoid hot spots for a large space is to use several pairs of loudspeakers evenly spaced throughout the room. A good rule of thumb is to install a pair of loudspeakers for every 200 to 400 square feet of listening area. Your local Niles dealer is a good source for advice on loudspeaker placement for your particular installation.



When using more than one pair, it is usually best to alternate a left channel and then a right channel, so that you have the best possible stereo coverage possible.

The position of the loudspeakers and their surroundings play a very important role in how a stereo image is created. You should experiment to find the very best position for your loudspeakers. Here are some guidelines to make the process quick and easy.

Figure 4

Illustration depicts the optimum placement zone for a listening distance of ten feet.

Make sure you are not blocking or reflecting the sound off of furniture or other objects. You should have a direct line of sight with the front of the loudspeaker. To determine the best position, measure the distance between the ideal listening position and the wall you plan to mount the loudspeakers on. Try to place the loudspeakers so that they are at least one-halfthe listening distance apart (this maintains a large, pleasant stereo “image”) and less than the entire listening distance (this avoids a“hole-in-the-middle”effect). For example; if you are ten feet back from the wall, the loudspeakers should be between five and ten feet apart (See Figure 4).


If possible, mount the loudspeakers between eight and twelve feet high. The less the downward angle of the loudspeaker, the further the sound will carry. If the sound is carrying into areas where you do not want sound, try pointing the loudspeakers more downward, this will reduce the amount of sound further away from the loudspeaker.

You can control the loudspeaker’s bass output by placement. This is called the boundary effect. You will get more bass response by mounting the loudspeaker directly to a wall or other flat surface (any boundary close to the loudspeaker will reinforce the bass frequencies). You can increase the bass output even more by mounting the loudspeaker in a corner or under an eave (See Figure 5) This type of placement gives the loudspeaker two boundaries, thus reinforcing the bass sounds even more. Of course, if you wish to hear less bass, try moving the loudspeaker away from the boundary (See Figure 6).


Figure 5

Figure 6

Placement for more bass output

Placement for


less bass output

Mounting Methods

The OS loudspeakers can be mounted either horizontally or vertically. The bracket knobs will keep the loudspeaker angled correctly in any position once they are tightened. You can choose from three mounting methods to attach the loudspeaker to the wall, ceiling, or other mounting surface.

1.If the loudspeaker is never going to be exposed to sudden accidental impacts, wind, waves or earthquakes you can simply hang it on a nail using the nail hole(s) on the bracket (See Figure 7).



Nail Mounting

Screw Mounting

Custom Bracket Mounting

Figure 7 TheOS loudspeaker can be mounted three ways.

2.The safest and most secure way to mount the loudspeaker is by screwing it to the mounting surface using your own hardware (suitable for the surface you are mounting to) and the bracket supplied with the loudspeaker (See Figure 7).

3.There is a threaded brass insert (1/4" – 20) on the back of the OS loudspeakers for attaching a custom bracket (See Figure 7). This allows you to position the loudspeaker at unusual angles or varying distances from the mounting surface.

Safety First!

Be careful to use hardware that is designed for the surface you are mounting to. The OS 5.5 loudspeaker with the bracket weighs 6 pounds. The OS 6.5 loudspeaker with the bracket weighs 9 pounds.The OS 7.5 loudspeaker with the bracket weighs 11 pounds. It is recommended to utilize attachment methods capable of supporting 10 times the weight of the loudspeaker and bracket.

Some local building codes require the use of an additional safety cable to mount loudspeakers on a wall. If so, the 1/4"-20threaded insert on the rear of the enclosure can be utilized for securing the safety cable to the enclosure. Construction of the safety cable and attachment of the cable to the wall needs to meet the local building codes.

If you are not sure of a safe way to mount the loudspeakers or are unsure of your local building codes, consult a professional installer or a building contractor for the proper installation techniques and requirements.

You will maximize the useful life of the loudspeaker, by placing the loudspeaker so that it receives less exposure to the elements. Look for the best overall compromise between sound quality, convenience, and exposure. Do not compromise safety.



The enclosure, the brackets, and the grilles of the loudspeaker can all be painted to match the surroundings. Because we want you to preserve the acoustic qualities of the grille, please paint the grille according to the grille painting instructions. Make sure you pick a paint that is appropriate for the mounting location. There are interior and exterior paint types, and even paint for marine uses. If you are not sure what paint to use, consult a paint store professional or a painter.

Tools Required

A spray can of primer paint

The correct paint for the environment/use (oil or water based paint is fine)

A paint brush or applicator if the paint is not in a spray can.

A paper clip or an awl (for removing the grille)

Masking tape

2 paint masks (supplied)

A damp cloth and a dry cloth

Preparing to Paint

1.Separate the parts of the loudspeaker. You should remove the brackets and the bracket knobs. Remove the grille by hooking it with a bent paper clip or the tip of an awl and pulling it away from the cabinet (See Figure 8).

Figure 8

Removing the grille using a paper clip




2. Wipe off the sides of the cabinet, the bracket, bracket knobs, and grille with a


damp cloth. Do not touch or rub the loudspeakers on the front baffle. Make sure





everything is dry before masking.



Mask off the binding posts and the brass threaded inserts on the back panel with


masking tape.




Mask off the threaded inserts on the top and bottom with masking tape.




Protect the front of the loudspeakers by inserting the supplied paint masks in



place of the grilles.

Painting the Cabinet, Bracket Knobs and Bracket

1.Apply two thin coats of a sandable spray primer to the cabinet and knobs. The bracket doesn’t require a coat of primer.

2.Allow the primer to dry completely.

3.Apply the finish color.

4.Allow the paint to dry completely.

5.Carefully remove the masking material.

6.Do not reattach the loudspeaker to the bracket until the bracket is mounted. Try to keep all handling of the freshly painted parts to a minimum.

Painting the Grille

The grille is important to the sound of the loudspeaker. Do not fill the holes of the grille with paint. The grille is constructed of aluminum with a perfectly even powder coat overall. This powder coat is an ideal primer.

If you are using a spray paint, use two thin coats without any primer. If you are using a compressor and a spray gun, use the finest, most diffuse setting. Practice on paper if you are not experienced in painting with spray paint.


If you are using an applicator or brush and a can of paint, thin the paint first. Thick paint will tend to clog the grille holes. To ensure a uniform appearance, paint the front and back of the grille.

Replacing the Grille

After the grille dries, carefully fit the grille into its recess so that it is barely in place. Starting with one corner, go around the loudspeaker, pushing the grille in a little bit each time. You should be gentle; the aluminum grille can be bent easily out of shape. You will feel a positive “snap” when it is in place.





Mounting the Bracket (if attaching the loudspeaker to a wall, ceiling, beam or other solid structure)

1.Loosen the bracket knobs and remove the bracket from the loudspeaker.

2.Hold the bracket up to the mounting surface. The loudspeaker can be mounted either horizontally or vertically. Hold the bracket so that the loudspeaker wire fits through the large, circular wire hole in the center of the bracket. Align the bracket to be square with the surroundings (use a level for accuracy).

3.Mark the locations of the three oval-shapedscrew holes (See Figure 9). Be sure to use all of the holes.

4.Drill pilot holes into the mounting surface.

Figure 9

Mounting the Bracket

5.Pull the loudspeaker wire through the wire hole in the center of the mounting bracket. Align the bracket so that the holes all line up.

6.Use your hardware to attach the bracket to the mounting surface.


Attaching the foot (if using the loudspeaker in a free standing mode)

1.Loosen the bracket knobs and remove the bracket from the loudspeaker.

2.Tighten the top knob so it does not vibrate.

3.Remove the bottom knob by unscrewing it from the cabinet.

4.Place the supplied shelf stand on the loudspeaker with the two shorter feet towards the front of the loudspeaker (See Figure 10). Make sure the ridges on the shelf stand engage the ridges on the cabinet.

Figure 10 Mounting the shelf stand on the OS loudspeaker

5. Tighten the bottom knob so that the shelf stand does not move.

Connecting the Loudspeaker

Bottom of the OS

1.Separate the two conductors of the loudspeaker wire so that at least two inches of each conductor are free.

2.Strip one half inch of insulation from the end of each conductor of the loudspeaker wire.

3.If you have any connectors (gold pins or bananas) which you prefer to use, affix them to the stripped wire ends now. Only gold plated connectors should be used outside as they will not tarnish or corrode.

4.If using the bracket to attach to a solid surface, slide the loudspeaker onto the bracket. Do not tighten the knobs completely. Angle the loudspeaker so that the rear terminals are accessible. If using the shelf stand, position the loudspeaker on the stand and place it on the shelf or table where you want it.




5. Connect one stripped wire end to the black and one to the red terminal. Pay

attention to the markings on the wire. Each loudspeaker wire must be connected



to the amplifier in the same way.


6. If required, attach the safety cable to the loudspeaker enclosure. See Safety First


section for details.


7. Verify that the loudspeakers are in-phaseas described in theLoudspeaker Phase




8. Angle the loudspeaker for the best sound possible.


9. Tighten the bracket knobs using only your hands. Use of any power tools may


over-tightenthe knob, and strip the threads of the insert.


10. Check that the entire installation is safe and secure.


Loudspeaker Phase


Loudspeaker wire has two conductors. One conductor is attached to the negative


(-)terminals and one conductor is attached to the positive (+) terminals of both your


loudspeaker and your amplifier. Usually, the wire is marked for your convenience.


There are different ways to mark the wire; a stripe, a ribbed area you can only feel,


different colors of metal wire on each conductor, or there might be a fabric strand


or string wound into one of the conductors. Of course, there are some wires which


appear completely identical. Be careful to avoid mistakes. If you do, one


loudspeaker will be playing out of “phase” with the other loudspeaker. An out-of-


phase pair of loudspeakers work against each other and the sound of the two


loudspeakers playing together will lack in bass and output. If you suspect the sound


is not right and you cannot see any markings on the wire, try this simple test:


1. Point the loudspeakers at each other, rather than at you.


2. Play some music with the amplifier or radio set to Mono.


3. Stand so you are the same distance from each loudspeaker and listen to the


richness of the bass and the loudness of the sound.


4. Turn off the amplifier and reverse the connections on one loudspeaker only.


5. Repeat the listening test with the same setting of the volume control. When the


sound has a richer bass and is slightly louder the loudspeakers are working


together or “in-phase”.



Listening at Higher Volumes

Outdoors there are no walls to reflect and contain the sound. It requires more power to achieve a reasonable volume of sound outside than it does when you are indoors. You also frequently find yourself very far from the loudspeakers. It is possible to turn the volume so high that the amplifier runs out of power.This creates “clipping” distortion.

Clipping distortion makes treble sound very harsh and unmusical. When you hear harsh sounding treble from any good loudspeaker indoors or outdoors, turn the volume down immediately! Those harsh sounds are masking some much more powerful ultra-high-frequencysound spikes which will quickly damage any fine loudspeaker.


You can clean the OS loudspeakers with a dampened soft cloth or paper towel. If the loudspeaker is mounted high up on a wall or ceiling, use a broom to gently brush it off. Hosing off the loudspeaker is not recommended, as the tweeter is a precise mechanism which might be damaged by a high pressure stream of water.





OS 7.5 Loudspeaker

Recommended Amplifier Power

5W – 150W

Nominal Impedance

8 ohms

Frequency Response

60Hz – 23kHz +/-3dB


91dB for 2.83V pink noise

Wiring Requirements

Sixteen to eighteen gauge 2-conductor(unshielded or shielded) wire for runs up to eighty feet. Fourteen gauge2-conductor(unshielded or shielded) wire for runs up to two hundred feet.

Dimensions (Loudspeaker with U-Bracket)

8-3/16"Wide x13-5/16"High x9-3/16"Deep

Weight (loudspeaker and Bracket)

23 lbs. per pair

2 Year Limited Warranty

OS 6.5 Loudspeaker

Recommended Amplifier Power

5W – 125W

Nominal Impedance

8 ohms

Frequency Response

70Hz – 23kHz +/-3dB


90dB for 2.83V pink noise

Wiring Requirements

Sixteen to eighteen gauge 2-conductor(unshielded or shielded) wire for runs up to eighty feet. Fourteen gauge2-conductor(unshielded or shielded) wire for runs up to two hundred feet.

Dimensions (Loudspeaker with U-Bracket)

7-7/16"Wide x 12" High x7-3/4"Deep

Weight (loudspeaker and Bracket)

18 lbs. per pair

2 Year Limited Warranty

OS 5.5 Loudspeaker

Recommended Amplifier Power

5W – 100W

Nominal Impedance

8 ohms

Frequency Response

95Hz – 23kHz +/-3dB


90dB for 2.83V pink noise

Wiring Requirements

Sixteen to eighteen gauge 2-conductor(unshielded or shielded) wire for runs up to eighty feet. Fourteen gauge2-conductor(unshielded or shielded) wire for runs up to two hundred feet.

Dimensions (Loudspeaker with U-Bracket)

6-1/4"Wide x9-7/8"High x6-3/4"Deep

Weight (loudspeaker and Bracket)

12 lbs. per pair

2 Year Limited Warranty