In-Wall Speaker Selection & Installation Basics
In-wall speakers are becoming more popular these days with aesthetics playing a major role in dictating the theater system components. In the olden days (think Pong), in-wall speakers typically didn’t offer the sonic chops to be taken seriously, but a lot has happened since then (think Call of Duty 4). Technological advancements in driver design, system integration and active room equalization is allowing enthusiasts to bring the Cineplex theater experience into their own homes, even when using all in-wall speakers and subwoofers. Of course this is assuming the right speakers are chosen and installed properly. This article explores some basic fundamentals for choosing and installing in-wall type speaker products in efforts to realize their maximum performance and yield the best possible experience to the end users.
Step 1: Choosing the Right Speakers
Before getting into the down and dirty on installing in-wall products, you must first choose the proper products for your application. In choosing the products, the first question you should ask yourself is:
Are these speakers being installed in an existing home or during pre construction?
If you answered “pre construction”, than it is highly recommended that you select speakers with back box enclosures as this provides them with a controlled enclosure space to yield better performance, particularly in the lower frequencies, as well as isolating their sound from transferring into adjacent rooms.
Some Examples of Back Box Enclosed In-wall speakers
Dali in-wall (left pic) Triad in-wall (right pic)
Assuming you are like most people looking to install a home theater into an existing room with the drywall already up, you basically have two options:
2. use free air in wall products and create your own back box or install a retro fit back box that some manufacturers offer for their products.
For those choosing option #2, I will show you how to create your own basic back box that although won’t replace a true enclosed speaker design, does incredibly well and is relatively easy to implement.
So your options include in-wall, in-ceiling, in-wall/on-wall hybrids or flat panel mount speakers. The focus here is in-wall and in-ceiling products but many of the guidelines I outline can be utilized for all of these speaker types.
Step 2: Positioning the Speakers
Speaker Placement General Illustrations
A good starting point is to go with an ITU 7.1 recommendation for speaker placement with some excellent placement notes courtesy of Soundoctor which is also very compatible with the THX recommendation as per the diagrams below. Since most rooms are rectangular, the THX diagram is usually a more practical layout.
ITU Speaker Layout (left pic) THX 7.1 Speaker Layout (right pic)
The Front LCR Speakers
Speaker positioning is perhaps the most important consideration when fidelity is of concern. Ideally the three front speakers (Left, Center, Right) should be placed at ear height (seated position) as close to equidistant from the listening area as possible to provide the most direct path of audio between the speaker and the listener - line of sight if you will. If you can’t manage equidistance, be sure to compensate via the receiver/processors time management circuitry.
Utilizing in-ceiling speakers for the front three channels is usually not advised for those concerned with fidelity of playback, especially for music. Placing a speaker too far off axis from the listening position not only hinders its high end frequency response and off axis power response, but can often lead to that “voice of God” effect which is more prominent for the front three speakers than the surrounds since human hearing is far more directional in front of your head than it is to the sides or behind. I highly recommend reserving in-ceiling speakers for the front three speakers as a last resort only.
For more information on how we perceive sound, check out our articles on Human Hearing.
Ideally you would follow the same placement guidelines for box speaker surround installs which are two side channels placed slightly above ear height and slightly back from the listening area (depending on speaker type) and the two direct radiating back channels at the same height about 6-8 feet apart depending on the distance to the listening area (80% separation from the distance to the listening area is a good rule of thumb here). In my application, I installed two in-ceiling speakers as my bedroom system is a 5.1 system.
In the Audioholics showcase Master Bedroom, I was fortunate to have access to the house during pre-construction and thus chose to integrate dual in-wall subwoofers with back boxes. I placed them about ¼ the length of the front wall from each side wall so that they would be roughly equidistant from the bed. Using two subs is always preferred as it provides better and more uniform bass distribution to a wider listening area, as well as increasing the maximum available output.
Placement is critical and it is recommended that you try to use symmetry relative to the listening area when placing multiple subs in a room to minimize path differences and ensure they properly acoustically sum to avoid cancellations or overly boosting certain frequency ranges.
For placement guidelines, please consult our article: Subwoofer Placement – the Place for Bass.
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Recent Forum Posts:
Are there sonic problems associated with in-wall speakers and how the sound reflects off the wall aligned with the front baffle? You wouldn't need a BSC circuit in your crossover
What about building a sealed speaker box and putting it into the wall? Any difference compared to mounting it on a stand 18" in front of the wall?
I ask because my bonus room has roughly 6 feet of attic space behind the walls. I may flush mount speakers and subwoofer(s) in the future if the sound will not suffer from doing so.
I realize ported speakers in a flush mounted configuration could only work if they were front ported.