SHOPPING CART

No items in cart.

• Order Status
• Payment Options
• Why buy from CAV?
• CAV News
• Technical Help
• Security & Fraud Policy
• My Saved Carts

• Get TechSmart! Knowledge Center

 

In-Wall Speakers
The Truth About In-Wall Speakers

Figure 1: In-wall Speaker Image

Terminology

Just so you know that you are reading about the correct subject, here are other names commonly used to search for this topic:

• In-Wall Speakers
• In-Ceiling Speakers
• Inwall Speakers
• Wall Speakers
• Wall Mount Speakers
• Speaker Wall Plates
• Flush Mount Speakers
• Speaker Wall Brackets
• Invisible Speakers
• In-wall Surround Sound Speakers

Note that since the industry has not yet settled on definitive names or spellings, we will use the following term compositions, “InWall Speaker”, “Inwall Speaker”, and “Wall Speaker” interchangeably within this article. You may find that some other terms may have alternating configurations too.

An Introduction to In-Wall Speakers

So you want to know about In-wall speakers? Want to make the right choice for you? Well, you have come to the right place. Simply and easily, this article will help you understand “In-Wall Speakers” and how to choose them without you being stuffed with marketing jargon along the way. This information has been written to provide the information that will allow you to make a more informed decision for your purchase or contracted installation. This article has been written, as much as possible, in friendly “plain English” so that you can understand the concepts as easily as possible. Common questions are presented, and then answered.

To meet your needs or budget, at various points and at the end of this article you can see links to recommend in-Wall Speaker brands and products. The experts at Contractor’s A/V.com, so as to make your decision even easier, have evaluated and approved of the in-wall speakers that are recommended.

Understanding the design and purpose of a particular speaker the fundamental knowledge necessary to utilize it properly. Some In-wall speakers are designed for some, but not other types of use. See Figure 1 as it is a typical in-wall speaker. Read on to learn more.

In-Wall Speakers or In-Ceiling Speakers?

This is the most popular question to address and clarify. Here, we are addressing “In-Wall” Speakers,” not “In-Ceiling Speakers,” although their designs and purposes are somewhat similar. In-ceiling speakers existed for commercial applications first, and were the predecessors of in-wall speakers. However, in the latest generation, in-wall speakers preceded in-ceiling speakers. The new generation of in-wall speakers were being used in walls and ceilings for many years, so a new breed of speakers developed with appropriately modified characteristics that we now call “In-Ceiling Speakers.”

Here are the fundamental differences between them:

First, generally in-wall speakers are rectangular, and in-ceiling are round. This is due to the fact that round ceiling speakers match light (and other) fixtures better, and rectangular (or square) in-wall speakers match the squared lines of walls including the vertical and horizontal features commonly found on them.

Figure 2: Horizontal Listening Plane

Second, in-wall speakers are most useful for applications where propagation on the horizontal (effective) listening plane is desired. (See Figure 2) This, of course, means that they are often a decent choice for home theater applications, stereo listening, etc. Usually this type of horizontal listening plane usage is not as effective for distributed (background) type applications, although in-wall speakers may be used for such. This is due to the fact that the objects often block the signal path and the signal may not be distributed as evenly as it would be from above, such as with a strategically placed ceiling speaker.

In-ceiling speakers are often designed to accommodate their location in the ceiling that may include both physical and performance criteria. Some in-ceiling speakers may even have a specific propagation axis for the direction of sound that accommodates a specific listening position, such as for home theater. More about those features later.

If you would like to know more about in-ceiling speakers, read more about them in the Contractor’s A/V.com TechSmart™ Article:  The Truth About In-Ceiling Speakers.

Click on this link for recommended in-wall speakers.

Click on this link for recommended in-ceiling speakers.

What is an In-Wall Speaker?

Don’t worry, we will not go into a rigorous technical explanation here, and everything will be described rather simply. The basics present enough to understand the concepts. However, so that we can convey the concepts effectively, we will get you used to the correct terminology. An individual transducer commonly named a “Woofer,” “Mid-range” or “Tweeter” is properly and individually known as “driver.” The entire speaker assembly we will refer to as a “loudspeaker,” but for sake of simplicity we will use the term “speaker” when appropriate to describe the entire device, i.e. frame/enclosure, driver(s), cross-over, etc. Also, it should be mentioned that most in-wall speakers are “direct radiator” type speakers. Simply put, this means that the sound propagated from the drivers goes straight to your ears instead of being manipulated acoustically or reflected in some way.

Let’s begin by saying that the physics of a driver’s proper performance requires that the waveform propagated at the front of the speaker be isolated from that of the rear of the driver. If the opposing waveforms meet at the proper frequency and time, then cancellation (no sound) occurs. This form of isolation for drivers is properly known as a “baffle.” A baffle can exist in many forms however. Most commonly, an enclosure commonly referred to as a “speaker box,” performs the function of isolation for the driver or drivers. A sealed speaker box, properly known as an “enclosure,” infinitely isolates or “baffles” the driver’s opposing waveforms, which is known as an “Infinite Baffle” enclosure.

Considering all of this, a wall can, rather conveniently, be used as an infinite baffle too. Back around two decades ago, some innovative companies came up with the idea to do just that. Enter, the In-Wall speaker! After that, scores of others followed with their own interpretations of in-wall speakers, and surprisingly most looked very similar from the exterior. Don’t be deceived though. Despite their similar exteriors there exists vast differences in quality, performance and reliability among them.

Most In-Wall speakers look very similar by virtue of their (exterior) bezel and grill. However, the entire design and overall make-up should be considered to choose one type of in-wall speaker for an application.

An in-wall speaker’s fundamental make-up is as follows:

• Bezel – Supports the entire structure, and may be considered the “Frame.”
• Drivers – An entire speaker assembly usually contains one to three drivers.
• Crossover - Divides the audio band, and sends the appropriate signal to each speaker.
• Grill – Covers the speakers, and allows sound through.
• Mounting Brackets – Keeps the whole assembly in the wall.
• Transformer - Changes the impedance from high to low for commercial 70V or 25V systems only.

What Types of In-Wall Speakers Exist?

Many types of in-wall speakers exist, and the differences may not be obvious, unless you know how to differentiate them.

Designed for General Purpose Applications.

In-wall speakers are designed either for general-purpose use or for specific applications.  Most “standard” in-wall speakers contain two to three drivers that are mounted on one (flat) plane, typically the bezel. Most In-wall speakers fall into the “General purpose” category, and, if configured properly, can work well for a variety of applications as described in the following topics.

Designed for Home Theater and Surround Sound

Although most in-wall speakers may be used effectively for home theater applications (with a proper configuration), some in-wall speakers employ designs for specific purposes such as for home theater applications. One of the most common of this type is that for home theater surround applications. These unique in-wall speakers come in many forms such as adjustable or di-pole. In some other cases, such as for a di-pole speaker arrangement, part of the speaker assembly resides within the wall, providing a somewhat less unsightly solution. Some of the latest even have motor assemblies and a control unit that has stores memories for varied configurations.

Esoteric and Unique Designs

Other in-wall speaker designs may include a number of deviations from the standard type mentioned above.

Surround Sound Speaker Designs

Some are utilized for the purpose of home theater rear “surround sound” type speakers. The surround sound type speakers are commonly offset so as to provide improved directionality, and in some cases they do. In other cases, the surround designs provide much less of an appropriate path with many acoustic problems before the wave-front even leaves the speaker. The lesson here is to be careful when making a choice for an in-wall speaker. Gimmicks are common, and “marketing speak” pervades.

Integrated Wall Speakers

Recently, some manufacturers have begun to deviate from the standard rectangular shaped bezel (frame) design where the diaphragm becomes an integral part of the wall itself. These “integrated” in-wall speakers are a departure from the common designs, although some may be rather useful. Their respective performance and ease of installation varies significantly, so due to the vast number of configurations, they will not be discussed further here.

Where and Why Should I Use In-Wall Speakers?

In-wall speaker types are often mixed and matched to a variety of applications. They can be a better solution than box, cabinet, or “on-wall” speakers when used correctly. In-wall speakers are a simple, efficient and elegant solution for many types of applications. Unfortunately, commonly used configurations are sometimes to the detriment of the overall purpose such as that for home theater, distributed or multi-zone audio. Be sure to configure your system appropriately for the best results.

Most will fit into typical drywall, sheetrock, or gypsum walls, between the studs, of course. Usually they have innovative support brackets that hold them in the wall. These simple and interesting brackets often self-adjust and progressively apply pressure from the rear. Note that when planning, it is wise to leave some space, usually at least a couple of inches, between the studs for the brackets.

Although doing otherwise may work sometimes, generally it is best to use an “In-Wall Speaker” in a wall, and an “In-Ceiling Speaker” in a ceiling. Why? Because there can be some significant design differences between them. The most significant difference is that ceiling speakers are often taller or deeper than an in-wall speaker that is designed to be shallow. Conversely, an in-wall speaker may be designed to perform better in a wall’s stud-bay as opposed to a ceiling’s environment.

Limited Space Situations

In-wall speakers prove to be an excellent choice for situations where space is limited, and a wall is available. Consider though that they must still be placed strategically so as to deliver sound on the desired axis (line of direction).

Aesthetic Appeal

In-wall speakers are a great option where you do not want to see much. This is due to the fact that, in most cases, the majority of the assembly is inside of the wall. Some exceptions to this are in-wall di-pole surround speakers that must protrude for the sake of clearing the wall surface by virtue of their function. Another exception is automated, adjustable in-wall speakers in that they must move into a position that is usually outside of the wall. Nonetheless, much of the assembly still remains inside of the wall and looks better because of it.

Speaker Enclosures May Not Work Well

In some situations, it is not desirable or even practical to mount a speaker enclosure on a wall. This could be for a number of reasons, such as safety, aesthetics, budget, etc. In this case, in-wall speakers are often a good solution. One significant compromise in this situation is that of not being able to articulate (move and direct) the speaker into the optimal position. The use of home theater type in-wall speakers proves to be a better choice for this application.

Layout Basics: How Do I Use In-Wall Speakers?

Here we explain the most common applications for in-wall speakers. Note that a true, in-depth attempt to configure a listening space is not for the faint of heart in that it can be a substantial amount of effort and calculations. However, our objective here is not to overwhelm, but to recommend some fundamental best practices for proper in-wall speaker configurations.

There are three primary uses of in-wall speakers; general listening (including “background” listening), “Home Theater” and  multi-zone distributed audio purposes.

General and Stereo Listening

The simplest means to listen with in-wall speakers, not associated to localized video, is to use a simple stereo set-up for a more “critical listening” environment.  This is not meant to be for distributed sound as that application may also have a stereo configuration, but is more a “background” type listing situation.

It is best to use many of the same principles that you would with speakers that are external to the wall. Optimally, the in-wall speakers should be placed on the “horizontal listening plane.”

The height or vertical dimension for the appropriate horizontal listening plane is determined by the height of your ears from the floor in whatever listing position your prefer. Its intersection with the wall determines where the center of the speakers should be placed. Simply, sit in the primary seating position, measure the height from the floor to your ear canal. This measurement will be the optimal height. It can deviate, usually higher, but ideally should not be more than 18 inches above.

Find the vertical centerline. For this measurement, simply find the left to right center of your listening space and mark it. Usually this is directly along the center of your listening position if it is not the center of the room. The speakers’ horizontal placement dimensions can be determined by locating them 30-40 degrees to the left and right sides of the vertical centerline. With a protractor, measure an angle of 30-40 degrees from the centerline of where your head would be for listening in the primary seating position. Locate those two points on the wall, to the left and right of the centerline. Those will determine the horizontal locations of your speakers’ center-point. Note that both speakers should be an equal distance from the centerline, so make the necessary adjustments.

Home Theater

Home theater layout is one of the most commonly misunderstood issues, and is commonly mis-configured. This is especially true with regard to the use of in-wall speakers due to the limitations of their mounting methods as opposed that of wall mounted or freestanding speakers. In-wall speakers can be used for this purpose quite effectively, but some factors should be considered.

Home theater is a unique application in that the purpose of the audio signal is to compliment the video image, and the speaker configuration is dependant upon the orientation of the image. This concept is known as “localization,” and, again, refers to the orientation of the speakers with respect to the image. Home theater speaker layout is a topic for another article, so it will not be addressed completely here.

In-Wall Distributed Audio Systems for Entertainment

This issue can be rather involved for optimal results, but fundamental rules, if followed, can achieve good results for an in-wall distributed audio system.

Mono In-Wall Speakers

The use of one in-wall speaker per zone is not uncommon where only a monaural (one channel) signal is desired. This type of configuration is most commonly used in commercial applications, particularly for paging or public address type systems.

Two Stereo In-Wall Speakers

Stereo audio signal can, of course, be used for background listening or for localized purposes such as for a TV or other video device. A stereo pair of in-wall speakers, or multiples of them may exist within each zone too, depending on the application.

Stereo Multi-Zone Audio

Multi-zone (distributed) systems are the most common uses of in-wall speakers. They may be used for primary (not background) listening. For stereo imaging to work effectively with this application, there must be consistency between the stereo pairs. In other words, the speakers should be placed so that the left and right channel signals are separated with some primary listening position as an objective. Consider the horizontal listening plane when evaluating this issue and determining the set-up.

In the case of multiple sets of speakers, keep consistency in mind. All left signal should be placed on one side of the zone and all right on the other. Don’t mix them. Consider the primary listening positions(s) and again, the horizontal listening plane.

Stereo Background Music

As mentioned previously, in-wall speakers may be used for background music as well as a number of other application types. If this is their primary function, remember to follows the rules of set-up for Stereo in-wall speakers. Note that in-ceiling speakers may yield better results for a multi-stereo speaker pair type application.

Distributed Audio for Public Address or Paging with In-Wall Speakers

Generally this is a commercial application, and is not a good idea to use in-wall speakers for this purpose due to proper coverage considerations. However, although not ideal, in-wall speakers can be used for this purpose under certain circumstances.  In-ceiling speakers typically work better for the sake of coverage.

Importance of Speech Intelligibility for Distributed Audio Systems

Distributed audio systems have existed for much time in the commercial realm in many forms, and are used for background music or public address. As of the last ten years, similar products and design philosophies developed for consumer use in residences. Regardless of whether the system is used for a business or home, for music or public address, intelligibility reigns. If in-wall speakers must exist for a distributed application, some basic configuration rules should be followed. After all, what good is a sound system if the details of speech or musical details cannot be understood? More often than not, intelligibility is overlooked.

Multi-Zone Audio Systems

A “multi-zone audio system” may be derived from distributed audio applications, music and speech. It is an extension of such in that speakers (or groups of them) are divided into logical “Zones.”  Note that a “zone” of a “Multi-zone” system can be either an entirely isolated area such as a separate room or it can simply be a particular coverage area of an open space. In-wall speakers can be used for this application as mentioned above, but effective applications of them are limited. In-ceiling speakers are typically a better choice.

Do I Need In-Wall Speaker Wire?

The answer is definitely “Yes.” Here’s why. By virtue of the fact that in-wall speakers are actually in the wall requires that the wire be too. All wires within the wall for the sake of safety and code compliance must be Class 2 or Class 3 for most residential applications. You will find most in-wall speaker wire is rated Class 3. Note that the “Class” of a wire is determined by its characteristics set forth by the National Electrical Code (NEC). If you are at all unsure of how to run wires safely, consult a professional.

If in-wall speaker wire is used in commercial applications safety and code compliance may require utilizing conduit or plenum grade wire. It is best to check with your city’s authorities for details affecting your installation.

What About In-Wall Speaker Installation?

Installation of in-wall speakers is quite easy with the right tools. They are designed that way. Always follow all safety precautions and installation rules provided by the manufacturer. Consult the manufacturer and/or a qualified professional if you are not sure of any step during the installation.

Installation Considerations for In-Wall Speakers

Before installing in-wall speakers, some foresight can help yield better results. These tips may offer some Of course, always use common sense when installing or placing anything, especially an in-wall speaker. Always use the manufacturer’s installation instructions as well.

Beware of Hazards

Always thoroughly examine the areas before deciding on a place for in-wall speakers. There are ways to identify common hazards such as wiring, excessive heat/cold, structural members, etc. Consulting a professional is the best practice.

Bordering Walls and Sound Transmission

Consider that any in-wall speaker that is installed in a wall will usually propagate sound within the wall and out of the opposing side too, depending on the wall design and the volume at which the speaker played. This means that you should consider opposing rooms or spaces that may be imposed upon by the sound when a speaker is playing. Insulation may assist with dampening some of unwanted sound transmission, but full isolation can require a substantial effort and materials. The idea here is to examine any room or space that could potentially be affected by the speaker placement.

Exposure to Elements

When choosing a location for an in-wall speaker it is wise to consider exposure to elements. Heat or cold, the weather, ducting, vents, fireplaces, etc. may adversely affect your speakers, particularly over time. Excessive sunlight is another element that is often overlooked that can deteriorate the integrity of yours speakers as well. Cold can cause moisture within components and eventually cause many of the components to crack or deteriorate. Heat even at relatively low levels can melt or distort components. None of these occurrences are safe, so look for them.

How Do I Choose an In-Wall Speaker?

Choose an in-wall speaker by the features that you need. Depending on your needs, specific features may be more appealing than others. Some layouts may actually require specific features. The tough part is that many manufacturers do not assess features such as specifications in exactly the same way due to varied testing methods or the lack thereof.

First consider the basic in-wall speaker features as follows:

• Power (Watts) – Indicates the electrical power handling capacity, relating to the amplification.
• Frequency Response – Indicates the range and regularity or the frequencies across the audio band.
• Sensitivity – Indicates the level of response based on a referenced amount of signal.
• Number and Type of Drivers – Determines the general performance characteristics and potential.
• Moisture Resistance – Necessary for outdoor or high-moisture situations such as bathrooms.
• Aesthetics (Looks) – Types vary from virtually undetectable to very obvious.
• Quality – Determined by many factors including overall design, performance brand, etc.

Other Application Specific Features of In-Wall Speakers

Some applications require specific features and allow better functionality and integration with the rest of the system.

Consider the following common features:

• Mono/Stereo Configuration – Accommodates one or two channel signal.
• Weather/Water Resistant – Provides better resistance to moisture and weather elements.
• Infrared Eye Port – Allows an infrared (IR) receiver to be mounted on the bezel.
• Bass & Treble Controls – Allows basic high and low frequency adjustments per speaker.
• Offset Axis/Directional Drivers – Provides the propagation of sound focused on a specific path or location.
• Adjustable Tweeters/Mid-Range Drivers – Allows the propagation axis to be adjusted.
• Connection Type – Accommodates one or more types of connectivity ranging from bare wire to a variety of specific wire terminations.
• Rough-In Bracket (Optional) – Provides a specifically placed and properly shaped opening for newly placed dry-wall.

Click on the link for recommended in-wall speaker wire products.

Click on the link for other recommended speaker wire products.

Can I Use a Subwoofer with My In-Wall Speakers?

Subwoofers are an excellent addition to most in-wall speaker configurations. They provide the low frequency signal below that of what most in-wall speakers (with a high and mid-frequency driver) can provide. There are two significant types, in-wall subwoofers and floor-standing subwoofers. Further, they may or may not include an integrated amplifier. A subwoofer (or other type of speaker) with an integrated amplifier is known as an “Active Subwoofer,” whereas one without is known as “Passive Subwoofer.”

What Size or Type of Subwoofer Should I Choose?

Subwoofers for home use often contain a single low-frequency driver commonly known as a “Woofer” or, in this case, a “Subwoofer.” There are many factors that affect the design and use of a subwoofer. For the sake of ease, we will only address some fundamental guidelines for choosing one.

Of course, there are some criteria to consider that affect the use and performance of a subwoofer. They include the overall quality of design, frequency response, inputs, controls, and the true amplifier power. These may affect your choice as well. Note that the objective of choosing subwoofer is to obtain one that can compliment the in-wall speakers that you have chosen to use.

Floor Standing Subwoofers

By virtue of the physics of low frequency drivers, they are substantially larger in relation to that of the high and mid-frequency drivers. This combined with the fact that human beings cannot localize sound (roughly) below 130Hz, means that for practical purposes they may be a completely separate assembly. A floor-standing subwoofer works well in this case, especially when space is not an issue. They can perform more predictably since they have been built and tested to do so.

Also note that floor-standing subwoofers can be active or passive. A passive subwoofer will require a separate amplifier that may reside with the amplifier(s) for the in-wall speakers in your system. Consider that you will likely need to run additional wiring if you decide to use one.

Click on this link for recommended subwoofers and active floor-standing subwoofers.

In-Wall Subwoofers

In residential environments, in-wall subwoofers are usually passive in that cooling, connectivity, power, limited wall thickness and code compliance are difficult issues with which to contend, if an active subwoofer were used. However, active in-wall subwoofers are starting to emerge, and can work rather effectively. In-wall subwoofers can be an effective option for almost any in-wall speaker system, especially if space is limited and aesthetic impact is an issue.

Click on this link for recommended in-wall subwoofers.

Subwoofer Driver Size

A popular questions is “What size Subwoofer should I choose?” To address this issue, once again, there are some basic concepts to acknowledge. The size of the driver utilized in the subwoofer determines the volume of air that is displaced when the driver is moving, thus the low frequency capabilities of a larger driver will provide more sound pressure level and lower (audible) signal as driver size increases.

As a rough gage, most systems in a small room (12 foot x 12 foot) can effectively use an eight-inch or ten inch driver design. However, if you desire to hear the lowest frequencies of your audio signal, then larger is better. Larger rooms may need to consider a twelve-inch driver, or even two, depending on the performance capabilities of the rest of the system. Remember too that a subwoofer with equalization controls (such as for Bass, Treble, phase, and cross-over point) allows one to adjust the level to match the rest of the system’s performance.

Other Types of Issues or Products to Consider for Use with Your In-wall Speakers

There are other products that may be necessary to make your in-wall speakers work properly and effectively. Here are some to consider along with the information for a basic understanding of each.

CL3 In-Wall Speaker Wire

In-Wall speakers require that, of course, the speaker wire supplying their signal be in the wall too. This means that safety is paramount. Class three speaker (CL3) wire is the best to use for in-wall speakers in that the wire you use should meet the requirements set forth by the National Electrical Code (NEC).

Click on this link for recommended in-wall speaker wire.

Distributed Audio System Amplifiers

Your in-wall speakers will require one or more audio amplifiers to supply them with amplified signal. There are a few methods to accomplish this as described below:

One Channel Amplifiers

One channel monaural audio amplifiers are commonly utilized in 25V and 70V commercial systems. The basic premise of these is that they use the properties of a higher voltage, high impedance line to run long distances. A speaker with a transformer may be attached, in parallel, to the line at various points along it. The transformer changes the impedance, and as a result, the draw from the line which allows the speaker to function properly. This method is effective for long runs and works well since it is one “serpentine” line that allows the speakers to be attached at any point.

These One channel monaural audio amplifiers usually contain features that compliment such use, and are usually built with a commercial environment in mind. Although these types of amplifiers are an effective solution for commercial applications, they usually are not a good choice for residential applications.

Click on this link for recommended commercial audio amplifiers.

Two Channel Stereo Audio Amplifiers

Two channel audio amplifiers are one of the more popular methods used for residential distributed audio systems. They can range from a simple stereo receiver to a dedicated (discrete) audio amplifier.  However, once more than two pairs of speakers are used with them, an impedance matching device becomes necessary. (See “Do I need an Impedance Matching Device?” below for more information.)

Click on this link for recommended stereo amplifiers.

Mutli-channel, Multi-Room & Multi-Zone Audio Amplifiers

The best method to use for multi-zone distributed audio systems is a multi-channel audio amplifier. This method provides many individual audio amplifiers in one device. The advantages are many:

• Have fewer impedance matching issues since each amplifier can be loaded most effectively.
• Have individual control of each amplifier to each speaker or zone.
• Get better overall performance.
• Some have integrated paging features.
• Some have integrated control features.
• Most are easily expandable.

Click on this link for recommended multi-room amplifiers and multi-zone amplifiers.

Other Amplifier Methods

There are other distributed audio system methods that utilize CAT5 wire to distribute signal. Some of these methods send the audio signal along with control information to a control pad in each zone. The control pad contains a low power audio amplifier that then sends the amplified signal to the local speakers. This method may work for basic audio distribution needs, but the previously mentioned audio amplifier types make overall performance, upgrades and reconfiguration easier.

Do I need Impedance Matching Devices or Speaker Selectors?

As previously mentioned, once more than two (eight ohm) speaker pairs are used with an amplifier, an impedance matching device becomes necessary.  These are commonly known as “Speaker Selectors” or “Speaker Impedance Matching Devices.” Speaker selectors contain three channels or more. Note that when making a purchase decision, it is a good practice to buy a device that has another channel or two in case you want to add more speakers or zones to your system. Plus, there is the added benefit that the device conveniently manages the many wire terminations necessary then provides a single wire connection to the amplifier.

There exists a fundamental electrical theory, known as Ohm’s Law. When the electrical load imposed by a multiple speakers system is considered along with the acceptable load of a typical audio amplifier, there is significant mismatch. The theory behind this law indicates that the use of an impedance matching speaker selector will resolve this mismatch in that it modifies or regulates electrical the load for the benefit of the audio amplifier. For sake of simplicity, we will not discuss more of this theory it in this article, although it is important to acknowledge it. (For more information, see our article “The Truth About: Speaker and Amplifier Relationships)

Resistor Based Speaker Selectors

This design, from most manufacturers, provides a simple and cost effective means to use multiple speakers to a single amplifier. Typically they provide two impedance matching channels that are commonly used for stereo pairs of eight-ohm speakers. The two channels may be split into non-correlated (different) mono channels too. Some even come configured with an “A/B switch” so that a second amplifier may be used as an alternate. Note though, that most resistor based speaker selectors handle relatively lower power applications, usually 100W RMS continuous or lower. Always check your device for its power handling capacity.

Some may contain a bypass switch that allows the use of impedance matching volume controls, thus rendering the device just a speaker selector switch.

For the sake of impedance matching, a resistor-based device will sacrifice a significant amount of amplifier power into the resistors. (See more information about autoformers in the next section.)

Auto-Former Based Speaker Selectors

Auto-Former based speaker selectors can often be a better option.  Here are some of the benefits:

• Power - Autoformer volume controls offer a higher power capacity.
• Frequency Response - Autoformer volume controls offer improved frequency response.
• Heat - Heat dissipation is minimized.
• Efficiency - Power from the amplifier is used more efficiently.
• Simplicity - Some types of autoformer volume controls allow simple impedance matching features.

Click on this link for recommended impedance matching speaker selectors.

Do I Need In-Wall Speaker Volume Controls?

Most consider some sort of volume control to be a necessity for in-wall distributed audio system since they allow each zone’s speaker output to be adjusted as appropriate. First, volume controls can be used with either in-wall or external to the wall type speakers. They are commonly used since having an all in-wall system is often desired. Consider too that volume controls handle two channels to simultaneously control a stereo pair of speakers, with the exception of 70V/25V commercial types that are one channel, mono. They can be used to control just one channel if you desire to do so. The two most common design styles of volume controls are rotary knob or slide-switch types. Also, the styles can include Decora or integrated plate designs.

Speaker Selectors with Volume Controls

Instead of using an impedance matching speaker selector, an impedance matching volume controls, all set accordingly, may be used. These volume controls are virtually the same design whether they are used within a speaker selector, or if they are used as “in-wall volume controls” for a distributed audio system application. You might say, “Why ever use a separate speaker selector?” Although impedance matching volume controls may be convenient, there may be some compromises.

Some volume controls limit the range of adjustment that allows a “matching” adjustment of minimum impedance. If you desire to maximize the steps of attenuation (lowering of signal level), then separate volume controls and a speaker selector will be necessary.

Resistor Based Volume Controls

Resistor based volume controls can be an effective solution in the right circumstances. They offer value in that they are relatively inexpensive and simple in their design. When using them, amplifier power should not be scarce, but be within their specifications. The resistors, by their own nature, may significantly impose upon the power available for the speakers.

Autoformer Based Volume Controls

Autoformer based volume controls are usually a better solution than resistor based designs. They require minimal power dissipation compared to the resistor based designs, so the amount of power that is drawn from the audio amplifier by the circuit is maximized. Often, autoformer based volume controls allow adjustments for the sake of impedance matching.

Click on this link for recommended in-wall volume controls.

List of Recommended Products That Contractor's A/V.com has Evaluated

These products have been evaluated by our expert staff, and have considered the information presented in this article. You will find quality and value in each and every one of the products that Contractor’s A/V.com has listed.

Click on following links for recommended products: