Interview with mr. René Kellenberger (CEO and speaker designer of No-Limit Audio)
No Limit Audio is described as a Swiss company whose goal is to eliminate every boundary between music and its listener, focusing its expertise on the design and manufacture of loudspeakers. With more than three decades of experience in high-performance speaker design, the company approaches sound reproduction as an artistic experience that must be delivered with the utmost clarity and vibrancy. Its loudspeakers are not seen merely as playback devices but as instruments designed to convey the feeling of live musical presence directly into the listener’s living room.
Crafted from premium materials and featuring high-frequency drivers from the renowned Accuton brand, combined with intelligent acoustic solutions and meticulous attention to detail, these speakers deliver distortion-free sound with full-bodied richness and, above all, a lively and airy soundstage. Across product lines that meet various needs and aesthetic preferences, No Limit Audio aims not only for maximum fidelity but also for an emotionally moving listening experience. It is a proposition for those who wish to experience music in its most authentic and truthful form. The company is now represented and based at the premises of Sonus Hi-Fi.
The No Limit Audio model we experienced, paired with the famous YBA Passion amplifiers and the ultra-high-end Swiss Soulution electronics, is called Reference One. It is currently the top floorstanding model in the lineup, designed for music lovers seeking a natural yet highly “live” listening experience with exceptional resolution. A three-dimensional, tangible soundstage is among No Limit’s primary design goals for its floorstanding flagships, which are priced around thirty thousand euros.
The Reference One consists of two separate enclosures: the upper cabinet features an 18 cm glass-fiber mid-woofer and a 2 cm Accuton tweeter mounted in a small horn (forming a two-way monitor/satellite), ensuring outstanding resolution and transparency with minimal distortion. The separate lower cabinet, made from solid wood, houses the woofers and subwoofers. With two 22 cm drivers, it provides the music with a firm foundation, absolute clarity, and explosive low-end response.
The Reference One Series 2, as it is fully named, includes two satellite units and two subwoofer units, offering a frequency response of 58–30,000 Hz for the top modules and 32–60 Hz for the sub-bass modules, along with a sensitivity rating of 92.5 dB/W/m. The floorstanders are available in solid oak finishes (“white chalk” or “grey”) priced from €28,900 per pair, or in a high-gloss rosewood finish at €32,300. There is also a carbon-HDF and white high-gloss version available, likewise priced at €32,300 per pair.
· What defines a truly “high-end” speaker in your view — craftsmanship, materials, some kind of ‘advanced’ sonic charismas (please describe), neutrality or ‘personality’ ? Tell us more about your design philosophy and your history on speaker design.
For us, a truly high-end speaker is one that successfully eliminates all the traditional issues found in conventional hi-fi designs. This means there is no phase distortion, the crossovers are simple and use no resistors, relying only on 6 or 12 dB filter characteristics. The speaker should also have minimal membrane resonances, a resonance-free cabinet, and optimized micro-vibration damping in the drivers.
Additionally, high efficiency is achieved through lightweight membranes, the strongest possible magnetic induction, and aerodynamic optimization to minimize losses. In our view, a high-end speaker is one that cannot be further optimized, because every aspect of its design has already been perfected. After more than three decades of development, we believe we have found complete solutions to all traditional speaker problems—making our products represent the true pinnacle of speaker technology.
· Can you walk us through your design process, from the first concept sketch to the finished product of your best current model, the Reference One ?
When I was around 15 years old, my uncle gave me a pair of BRAUN speakers, although one of them wasn’t working anymore. I took out the tweeter and placed it on top of the speaker to investigate, and I discovered that the solder joint on the connecting cable had simply come loose. Once I reconnected the cable, I immediately noticed that the speaker—with the tweeter now sitting on top—sounded much better. There were two reasons for this improvement: No vibrations were being transferred from the bass unit to the tweeter anymore.The open hole where the tweeter used to be allowed the bass driver to breathe, since the cabinet was previously a closed design. The difference in sound quality was so huge that it inspired me to study loudspeaker design.
In 1992, at the age of 23, I opened my first hi-fi shop in Switzerland. By 1996, I began importing and distributing high-end audio systems—including brands such as YBA, VTL, Cambridge, Straight Wire, Audioplan, Totem Acoustic, and Acoustic Energy throughout Switzerland, Germany and Austria. In 2008, I sold my entire business to Euronics Switzerland and returned to my true passion: developing my own loudspeakers. Even the best speakers I had experienced never felt truly “high-end” to me—meaning they didn’t reproduce every kind of music with a completely natural, uncolored, and lifelike sound. The result of this lifelong pursuit is No-Limit-Audio—speakers designed to sound absolutely realistic, holographic, and natural, with no compromises and no limitations.
· How do you balance aesthetics with acoustics — form versus function — when designing your speakers?
For us, form clearly follows function. We use a clean, precise design language that allows us to create straightforward, timeless designs. This approach also enables us to work with exceptionally rigid cabinet materials, such as 27 mm solid oak or 24 mm tank-grade plywood.
· Many high-end speaker manufacturers, such as Stenheim or YG Acoustics, rely on aluminum or other enclosures, while others like ProAc, Spendor, or Sonus Faber favor MDF cabinets. Why do you choose to work with oak wood instead? Do you believe the other materials can’t achieve the same level of sound reproduction as your designs?
You know, aluminum is also a strong material, but it immediately starts to vibrate and ring (similar to a metal-dome tweeter). To control these resonances, you need to invest heavily in damping. In our opinion, it’s better to start with a hard but naturally stable material like solid wood, rather than trying to fix resonance problems afterward.
MDF, on the other hand, is basically compressed paper dust with a lot of glue — not really ideal for building a resonance-free high-end speaker. It’s just easy to shape, inexpensive, and simple to paint. Compared to MDF, which costs about €20 per square meter, our 27 mm solid oak panels cost around €500 per square meter — roughly twenty-five times more. But the acoustic benefits are immediately noticeable: higher dynamic range, greater transparency, and much clearer, more detailed bass.
· Many audiophiles talk about the ‘soul’ of a speaker. How do you ensure your designs convey emotion, not just precision? Or the emotion is clearly amplifiers & sources ‘job’ ?
You know, the true emotions lie in the music — not in the hi-fi equipment. When there’s no coloration, no phase distortion, and the dynamics are as high as with our No-Limit-Audio speakers, you immediately feel the emotions in the music. You don’t have to search for them.
· Do you prefer tube amplification or solid-state driving your speakers, and why?
We prefer fast, neutral amplifiers with high resolution for our speakers, but ultimately, the choice of amplifier type doesn’t matter—both technologies can deliver excellent results.
· How do you test and tune your speakers to ensure they reproduce music exactly as intended? Please tell us more about your reference or preferable equipment mating great with your speakers.
After completing development and measurements, our final evaluations are always done by ear. In our test room, we use components from YBA, Brinkmann, Jadis, and NBS—each among the very best in its field. And finally, there are my own ears; my colleagues in the company even call me the “Golden Ear.”
· What’s one design challenge you’ve faced that pushed your engineering skills to the limit — and how did you solve it?
One key aspect of our design is the proprietary waveguide technology used in the mid and high ranges. It ensures exceptional phase stability, minimizes the need for crossover components, and delivers up to 12 dB more dynamic range in the midrange frequencies. Equally important is our focus on reducing resonances wherever possible and optimizing the speakers’ aerodynamic efficiency. In a world dominated by wireless and smart devices, we believe there will always be true music lovers who attend concerts, the theater, or the opera—and they will never be satisfied with a simple Wi-Fi speaker. After years of dedicated development, I am confident that our speakers represent the pinnacle of loudspeaker technology. If I had to choose one album to showcase their capabilities, it would be The Road to Hell by Chris Rea—a beautifully crafted record with excellent production quality and a deeply emotional vocal performance.
For further information & details: No-Limit-Audio, Sirnacherstrasse 6 , CH-9500 Wil, Switzerland, Tel. 0041 76 380 71 11, www.no-limit-audio.com
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