The Cloak of Invisibility
One of the amazing things about loudspeakers is the incredible variety of sizes, shapes, colors, and finishes. For the audiophile or merely the person who has an interest in the technology itself, this a beautiful thing. There are other folks, though, for whom speakers are a necessary nuisance – at best considered an annoying piece of furniture that inevitably mucks up the ergonomics or décor-onomics (not a real word, but it gets the point across) of any room they’re located in. And that’s before accounting for the speaker cables and/or power cords running across the floor.
One solution is to use architectural speakers that are installed either in-wall or in-ceiling. This type of speaker not only offers the advantages of eliminating unwieldy or inconvenient boxes from the room, but it also gets rid of those ugly cables and wires that are so easy to trip over. It does not, however, eliminate the visual presence of speakers in the room, as nearly all architectural speakers utilize round, square, or rectangular perforated grilles. Sure, such grilles can usually be painted to match the color of the wall, but they remain a visible distraction from what might otherwise be a beautifully designed décor. Furthermore, if the room’s layout or wall/ceiling construction prevents installing the speakers in a symmetrical or similar eye-pleasing pattern, one or more of those grilles will stick out like a painted sore thumb.
The problems quickly multiply when you start adding multiple channels for a home theater system. As a result, homeowners, designers, and decorators have dreamed of the ultimate architectural solution: the invisible loudspeaker. Yet, short of some magic invisibility cloak straight out of Harry Potter (wand not included), how do you make a loudspeaker (or a 7.2.4-channel system of speakers) disappear?
Making Speakers Disappear
Although the sound quality hasn’t always been that great, invisible speakers of the non-magical type have been around for quite a while. Significant improvements have been made over the years, though, and there are now a considerable number of companies offering high-performance invisible speakers, including Amina, Nakymatone, Sonance, and Stealth Acoustics. Although each company differs in the particulars of its product designs, the ones under discussion here utilize a similar fundamental concept that involves installing an independent vibrating flat panel (rather than the usual cone/dome-shaped transducers) flush with the wallboard and then applying paint or other type of covering over it so it completely blends in with the surrounding wall. Of course, the entire process is much easier said than done. Unlike a traditional-style architectural speaker, invisible in-wall or in-ceiling speakers don’t have flanges surrounding the speaker grille – indeed, they don’t use grilles at all. Flanges can conveniently hide off-kilter, crooked, or roughly cut edges in the drywall opening that the speaker is mounted in. In addition, the face panel of the invisible speaker needs to be perfectly parallel with the wallboard but extend approximately 1/16th of an inch above the surface. This means that shims are often required during the installation to ensure the correct alignment.
Once installed, most manufacturers recommend using self-adhesive nylon mesh or paper tape along the edges where the speaker panel meets the wallboard and then feathering the speaker face to the wall with standard drywall joint compound. Depending upon the final finishing technique that’ll be used, a very thin skim coat can sometimes be applied over the entire face of the speaker. It’s imperative that imperfections in the joint compound be carefully sanded and corrected before the final paint (or other finishing) is applied in order to create a visually seamless transition between the panel and wall. Needless to say, unless you have extensive, professional-level AV installation, carpentry, taping and floating, and wall finishing skills, this is not a do-it-yourself project.
One advantage of invisible speakers (beyond being invisible, of course) is that the flat panel used to create and project sound into the room offers a much wider dispersion angle than do architectural speakers that rely on cone or dome transducers for mid- and, especially, high-frequency production. Whereas a typical in-room or in-wall speaker might have a relatively uniform high-frequency dispersion of around 30 to 45 degrees off-axis, invisible architectural speakers are often rated in the 80 to 90 degrees off-axis range. This is especially helpful in expanding the sweet spot to encompass more listeners as well as extending the coverage area in large rooms.
There are a couple of other issues to be aware of regarding invisible architectural speakers. Perhaps the most important is build quality and overall reliability. Just as an invisible speaker doesn’t go into a wall without a lot of effort, it doesn’t come out easily if it needs to be repaired or replaced –and, of course, the entire install process has to be repeated with the repaired or replaced unit. As a result, many companies incorporate built-in, self-resetting circuits, and/or high-pass filters to help prevent overloading the drivers to the point of failure. Furthermore, invisible speakers, like most architectural speakers, don’t offer the amount of bass output that many people look for when putting together a high-performance home theater or dedicated two-channel music system. Fortunately, there are also invisible subwoofers for folks who want the ultimate in stealthy sound.
Considering the company’s name, it shouldn’t be a surprise to anyone that Stealth Acoustics offers one of the most extensive selections of “totally invisible audio solutions” available today, including two models of invisible subwoofer systems – the B22G and B30G, which are sold and meant to be installed as two-panel systems.
The most impressive full-range invisible speaker system in the Stealth Acoustic’s lineup is the LRX-85, a three-way, two-panel system that the company says requires “no special bass-limiting filters, ancillary protection circuits or external subwoofers.” (If that’s not enough for you, there’s also an active, bi-amplified version, called the LRX-85ACT.) Because the bass-producing panel is separate from the mid/high-frequency panel, there is much more flexibility in terms of installation placement in a room. (The company suggests placing the two panels within one meter of each other.) Stealth Acoustics says that the LRX-85’s 300-watt power handling enables the speaker configuration to generate up to 105 dB of output with low-frequency response down to an impressive (for an invisible speaker, anyway) 35 Hz. Finish options include latex paint, flat finish, orange peel texture, light plaster, light wallpaper, light fabric, wood veneer, and other selected finishes.
In 1983, Sonance became one of the very first companies to make speakers specifically designed for architectural use. In the intervening years, the company’s product assortment expanded, and, as you would expect, it includes several models of invisible speakers. The two-way IS2 is “designed for tight installations or very small spaces,” while the larger, three-way IS4 is engineered for higher performance in larger spaces. The IS4 SST is a single-stereo speaker version of the basic IS4, while the IS4 C is one of the few invisible speakers on the market engineered specifically for use in 70- or 100-volt systems.
Sonance rates the IS2 and IS4 down to 50 Hz and 40 Hz, respectively, but the bass response can be reinforced invisibly with the company’s ISW dedicated subwoofer panel. The ISW uses two 2-inch voice coils to drive a 170 sq. inch planar diaphragm that Sonance says can reach frequencies as low as 35 Hz. Every IS-series speaker includes built-in, independent, self-resetting gel switches (for low, mid, and high, depending upon the driver configuration); and the planar paper surfaces can be used with up to 1/8-inch of flexible material – such as joint compound, plaster, or wallpaper – or paint.
Amina Technologies describes its invisible architectural offerings as “part loudspeaker and part construction material…designed to be just as much a rugged building material as they are a precise acoustic device.” The company’s Edge-series invisible speakers are meant specifically for applications in walls and ceilings constructed with drywall. During installation, the perimeter around the company’s Edge-series invisible speakers is filled, taped, and feathered before the surface is painted; but, since the Amina speakers in this series attach solely to the drywall, the company says that no special framing is required. Stylish interior décor often involves more than the standard skim-coat and paint, however. Amina’s Mobius-series speakers are engineered for installation in walls that don’t use drywall construction or situations where a specialist covering material is required.
The amazing variety of potential covering options includes wood, leather, natural stone veneer, wet plaster skim (up to 2 mm thick), acoustic or polished plaster, as well as composite material skins in various finishes, as well as a mirror finish. The Mobius-series speakers are so versatile in terms of installation and covering capabilities that they can even be integrated directly into furniture.
Aside from the unique company name and the penchant for using Dutch words for the models of its speakers, Nakymatone is unusual for the fact that each one of the company’s four models of invisible speakers includes an acoustically tuned anodized aluminum enclosure. Not only that, but the Echt, Mooi, Goed, and Twee also share the same overall physical (23 x 9 ¾ x 3 ½, HWD, inches) and required cut out (16 5/8 x 9 ¾, HW, inches) dimensions.
The numerically astute reader will notice that the enclosure is nearly seven inches taller than the cutout. This is not a mistake, however, as Nakymatone’s speakers are designed to be slid upward into the opening vertically. Once the bottom of the enclosure has cleared the lower edge of the cutout, the assembly is lowered until the surface of the raised acoustic panel, which has the same dimensions as the cutout, lines up with the edges of the opening. Once in place (and after alignment shims are inserted, if required), the enclosure is secured with screws along the outside edges at the top and bottom of the opening.
The Echt, Mooi, and Goed are full-range speakers with low-frequency outputs down to 60 Hz, 75 Hz, and 80 Hz, respectively. The Twee, named using the Dutch word for “two”, is a full-range single-speaker stereo model that matches the Nakymatone Goed in overall performance. The Laag (Dutch for “low”) isn’t technically an invisible speaker along the lines of the planar technology incorporated into the other Nakymatone speakers. Instead, it uses a cone woofer in a ported cabinet. The Laag’s 7.9 x 9.5 x 19.3 (HWD, inches) cabinet is too large to fit inside a standard 2×4 stud wall, however, so the enclosure is likely to be installed in a ceiling or closet. It includes a flexible tube that attaches from the output port of the subwoofer to a standard vent.
Although it doesn’t create true invisibility in the sense we’ve been talking about so far (with the exception of Nakymatone’s Laag subwoofer), another method of making a loudspeaker disappear is to camouflage it so it looks like something else – or at least looks like something that ought to be there. Typically, this involves concealing as much of the loudspeaker behind the wall or ceiling and allow the sound produced by the speaker to disperse into the room via a grille-covered hole in the wall that’s as small as is acoustically feasible. In most cases, the tiny grille is designed to mimic the appearance of a light fixture mounted in the ceiling.
Gray Sound, an architectural speaker company based in The Netherlands, offers two full-range models in the company’s Vox series. Although differing slightly in overall size, each model utilizes a square steel casing that mounts behind the drywall and is adjustable so that it can be aligned flush with the surface of the wallboard. After the ceiling is taped, floated, and painted, the speaker is screwed into the waiting housing, and the grille is attached.
The smaller of the two models, the Gray Sound C40 incorporates a four-inch round mid-bass driver with a coaxially aligned wide-angle titanium tweeter. (Gray Sound says the company’s tweeter provides up to 60 degrees off-axis of high-frequency dispersion whereas a “normal” tweeter offers closer to 45 degrees.) The cutout size is a mere 4.5 x 4.5 (inches), and the entire assembly requires a maximum of 3.2 inches of mounting depth. The Gray Sound C50 uses the same titanium tweeter mounted in front of a larger 5-inch mid-bass driver. Although the mounting depth remains the same, the cutout size to accommodate the extra width of the mid-bass driver is approximately 5.7 x 5.7 (inches).
The Gray Sound C40 and C50 are said to have frequency range output as low as 60 and 55 Hz (respectively). As such, for systems designed to provide more than a background music listening experience, the company suggests adding the S80 subwoofer. Incorporating an 8-inch woofer, the S80’s ported cabinet measures 7.9 x 9.45 x 19.3 (H x W x L, inches) and is designed to be mounted above the ceiling. A flexible tube connects to the port and directs the airflow output to a square grille that matches either the C40 or C50 in design, color, and size. The S80 is said to have a frequency response of 40 Hz to 117 Hz.
Hiding in Plain Sight
It’s often been said that one of the best ways to keep something secret – especially if you’re the military or a three-letter government agency – is to hide it in plain sight. Even if your intentions aren’t the sort of thing that would make a thrilling plot for the next Bond film, installing invisible architectural speakers in the walls or ceilings of your home is an excellent way of eliminating the physical inconveniences and visual annoyances of standard in-room speakers and traditional architectural speakers. Of course, there are trade-offs to be made when you go the route of invisible speakers, most importantly the additional cost and complication of installation. But once the speakers are installed and the paint, wallpaper, or other type of finish is applied, the speakers will be out-of-sight and out-of-mind – until you turn the system on. Then the fact that these speakers are meant to be heard and not seen will likely blow your mind and make you the envy of designers, decorators, and homeowners for whom the experience is more important than the components.