by Steve Olszewski, VP, Stealth Acoustics
Steve Olszewski is the Vice President of high-end invisible speaker brand, Stealth Acoustics. A diverse career has seen Steve as an audio/visual systems engineer, installer, musician and business owner. Since joining Dimensional Communications in 1976, he has overseen the growth of Dimensional’s Integrations business and the creation of Stealth Acoustics. He currently lives in the coastal Pacific Northwest, near Seattle, WA in the USA.
Here, Steve provides an insight into what specifics to look for when selecting an invisible speaker for a custom install, while also explaining the benefits that invisibles offer over their more traditional counterparts.
Invisible speakers have been around for a not-inconsiderable amount of time, yet are only recently reaching a market recognition and performance capability on a par with visible speakers. The unique aspects of having a high quality, invisible soundstage for home cinemas, critical listening and distributed audio in a residential property, as well as a commercial space, is a compelling proposition for AV installers, architects, interior designers and homeowners alike.
This trend is not just about hiding speakers; it’s also to do with taking the visible and ‘in your face’ aspects of technology and making it recede into the background. In other words, the drive is towards achieving the art of concealment without compromising on speaker performance.
Easily able to make a powerful aesthetic statement at the same time as they can deliver on both price and performance, invisible speakers offer a host of benefits. But it’s important to be clear that not all invisible speaker technologies on the market are the same. This has a major impact on the resulting sound, with some devices producing arguably audiophile quality and full spectrum sound and others performing far less well, whether it is in subjective aural quality or a measurable response.
Still, there are common elements to all invisible speakers, in addition to a few key differentiators.
Common to virtually all invisibles is the general method of taking electro-mechanical audio motors and using these devices to actuate a flat surface membrane with vibrations, resulting in the production of sound. Common also is the ability to mount invisible speakers into walls or ceilings and ‘float’ them with joint compound or plaster into the adjoining surfaces to create a homogenous, invisible (if installed correctly) blend of ceiling or wall and speaker. This provides a range of room layout possibilities not available with traditional units. Typical coverings or finishes for invisibles can include plaster, paint, wallpaper and even thin wood materials.
Traditional speakers are typically ‘full-range’ devices, usually extending between 35Hz at the low frequency spectrum and 18kHz at the upper. Music and other audio recordings fall within these parameters, with deep bass notes and sound effects like explosions reaching deep into the lowest registers of human hearing (around 20Hz). High frequency listening content can reach well into the upper limits of human hearing (around 20kHz), especially considering the overtones and natural harmonics that occur in music or other content. It’s also important to remember that output matters as well, with good speakers being able to reach over 100dB without sacrificing on clarity or response.
Not all visible speakers faithfully reproduce full range sound or provide high output, with the same being true for certain invisibles, but getting the best available invisible for your client’s budget is important. Natural bass extension, and high frequency response, if both are properly balanced within the unit, will allow most listeners to enjoy the content without complaint that “something is missing”. Reaching high SPL’s of clean output (typically measured at 1 meter from the device) is also desirable even if the speaker usually isn’t driven that loud, as the speaker components will be under less stress at lower volumes if able to handle a higher output, with peaks being more easily handled for increased reliability.
While almost any invisible speaker can reproduce for example, the range of a violin, even non-critical listeners appreciate solid bass response that drives emotion or provides impact, such as in action movies, certain orchestral works and modern music. Lacking such bass response, a speaker, invisible or not, will not be as well received as one that produces tangible bass down to about 35Hz – the lower notes of a double bass or piano. Assuming the remaining audible frequencies are reasonably well presented up to about 18kHz – the upper range of an orchestral triangle or cymbal – along with an extended bass response, most listeners will be satisfied when listening to a wide range of content. Adding invisible subwoofers into the mix can extend response down into the sub-bass region for even greater impact and realism, but invisible speakers with cone woofers typically only need subs for extremely low sounds, such as home theatre applications.
So what are the key differences with invisible speakers? Since all invisibles install in a somewhat similar fashion, the differences boil down to four essential elements; component and face material, frequency response, sound quality and of course, price:
Component and face materials
These vary widely between invisible speakers. Some use a single motor, some use multiple motors, while the best feature motors and cone woofers run through a traditional crossover just like regular speakers (such as the Stealth Acoustics LRG Series). Face materials vary widely and all affect sound quality. The best face materials provide a pleasing, natural resonance, are extremely durable and immune to moisture from paint, finishing materials or the surrounding environment.
Frequency response
Frequency response is measurable and if it gets down to the 35Hz range or below and up to the 18kHz range with a reasonably flat response, the speaker has the basics covered. Reading the speaker specifications is important, and the manufacturer should be capable of giving you an honest report of frequency response and output whilst exposing any limitations or special operating conditions.
Sound quality
Sound quality itself is somewhat more of a subjective consideration than what a response curve will imply. You must really listen to a speaker carefully to understand the subtle nuances in quality of sound reproduction.
Price
Finally there is price. It’s important to note that you can pay more for a less capable speaker, invisible or not, but this seems to be especially true with invisibles. Therefore, it’s important to do prior research and ‘try before you buy’ if possible.
So, if you’re considering invisible speakers in your custom or commercial AV installation, take the time for a listening demo and read the specs. Play full range music with a strong bass output and movie clips with explosions, or perhaps something orchestral with tympani, double bass elements and cymbals to expose the response of the speaker. Even better, play some dance music and turn it up loud – that’s where powerful speakers hold up and weaker ones fall down. Ask how the speakers are constructed and how they make sound, paying close attention to quality of build and looking for typical speaker components like cone woofers, crossover networks and protection circuits. In the end, a speaker is a speaker. They all couple mechanical vibration to air to make sound, and the best invisible speakers use components similar to visible speakers, just in a more creative (and hidden) manner.
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