Gauder Akustik Berlina RC 9

Theory Meets Practical Application

Equipment report
Gauder Akustik Berlina RC 9
Gauder Akustik Berlina RC 9

I first laid eyes on the $175,000 Gauder Akustik Berlina RC 9 loudspeakers at CES 2015. They were part of a system put together by Axiss Audio that included Air Tight reference tube electronics and the company’s Opus-1 cartridge mounted on a Transrotor Tourbillion ’table. That room earned my cost-no-object Best of Show award. The sound was full and rich with plenty of body and macro-dynamic oomph on an orchestral recording I brought along for audition. There was no hint of the edge, brightness, or sterility that has been known to plague certain ceramic-driver designs in the past. Instead, there was an exceptional portrayal of what was on the recording without any colorations that I could identify being superimposed by the speakers.

The Berlina RC 9 is a reference-quality four-way speaker system utilizing a ¾" pure-diamond tweeter, a 2" pure-diamond midrange driver, a 7" ceramic lower-midrange driver, and three 7" ceramic woofers paralleled in a 12th-order bass-reflex enclosure.

This completely custom creation is derived from the mathematical models developed for the speaker by Gauder Akustik. Without getting too technical, Dr. Roland Gauder, a physicist, uses Euler’s formulas to describe every parameter of the speaker system (drivers, cabinet, and crossover) and its performance characteristics (including vibration, oscillation, damping and decay of driver diaphragms, cabinet materials, and electrical components). Laplace transforms are then applied to create transfer functions from which the cabinet size, Thiele-Small parameters, and values of electrical components can be calculated.

Dr. Gauder’s physics-driven, top-down systems-design approach means there are no off-the-shelf driver solutions. Everything must be custom-made. For the drivers, the derived Thiele-Small parameters (along with additional requirements) are transferred to the manufacturer, who then produces the exact physical component specified via the mathematics. There is no room for compromise or deviation with such designs; the drivers have to be made precisely as ordered-up by Dr. Gauder. The German dynamic-driver company Thiel & Partner GmbH met this challenge, and was able to construct custom Accuton (diamond and ceramic) drivers for the RC 9. Strict adherence to specifications has resulted in drivers that are rigid and nimble and that have strong magnetic properties. These custom drivers perform, as required, without the modifications, patches, and accommodations typically necessary to fit or tune a driver into a loudspeaker.

The crossover network is also part of this systems-design approach. The RC 9 crossover moves into the rare area (for loudspeakers) of having greater than 60dB-per-octave passive networks, with less than half-an-octave of acoustic overlap between the drivers. Additionally, the four-way crossover network is symmetrical, which significantly increases its complexity, but Dr. Gauder feels the sonic results are more than worth the expense and effort for his reference Berlina RC 9 loudspeaker. The benefit of symmetrical crossover design (which puts components into both the positive and negative legs of the speaker connection) is said to be to a more natural sound, and an easier load on the power amplifier. According to Gauder Akustik, the components in the crossover are exclusively sourced from Mundorf and Intertechnik, ensuring consistency, quality, and reliability.

The bass section of the Berlina is unique in two ways. First, the bass is high-pass-filtered to 21Hz, so there is no need to be concerned about DC leakage current from the amplifier’s speaker output terminals or subsonic rumble from analog sources directly affecting the RC 9’s performance. The other feature is an equalization system that allows the bass to be tailored to the room. On the rear of the speaker there is an electrical selector plug for “Dynamic Bass Control.” The choices are a 0dB neutral setting along with a +1.5dB boost and a -1.5dB cut. If the selector plug is completely removed, the user will gain an additional setting that provides a -3dB cut. The effect of this room equalization is mostly, but not exclusively, observed in the 70–100Hz range where room peaks, lack of energy, and other anomalies are typically noticeable and may need to be controlled.

The RC 9 enclosure features a high-quality oval-shaped rib construction—from which the “RC” in the name is derived. The idea came to Dr. Gauder when contemplating how he thought nature would build a loudspeaker—like a human, with a sternum (faceplate), ribs (sides), and spine (for stability)—to enclose a volume of low resonance. Dr. Gauder chose the construction technique in order to suppress any loudspeaker’s inherent tendency to vibrate and add unwanted resonant energy to the sound. To accomplish his goal of removing as much vibration as he could, the Berlina RC 9 uses a stack of 50mm individual ribs separated by 4mm damping ribs. Gauder Akustik believes that these thick, heavy, stiff ribs create favorable conditions to keep vibrations from interfering with the speaker’s sonic reproduction of source material. To further reduce and isolate vibrations, each of the adjacent 50mm single ribs is structurally different. The RC 9 cabinet is constructed with 26 single ribs and 25 damping ribs. The front faceplate is 38mm thick with an additional 3mm of constrained-layer-damped heavy black flagstone that has a textured finish to further help break up acoustic resonances. The ribs are compressed together with six threaded rods, three on each side) that provide the necessary pressure to acoustically seal the enclosure. On the rear of RC 9 are two sets of WBT NextGen binding posts that allow bi-amp or bi-wire configurations. The bottom of the rib construction has the port for the bass-reflex system at a fixed distance from the bottom granite base upon which the speaker sits. This base is made of black Star Galaxy granite—which is what is used in the trim of some Mercedes-Benz automobiles, among other high-end stone applications—connected to the lower rib by three stainless cone footers. The single ribs are finished in high-quality, high-gloss piano white or black.

In late February of 2015, I received an inquiry about reviewing the Berlina RC 9. In mid-April, Gauder Akustik’s U.S. distributor Arturo Manzano of Axiss Audio in California and Dr. Roland Gauder himself flew in to install the Berlina RC 9s in my listening room. The speakers arrived in individual wooden crates, side by side on a single pallet. To begin the installation, the top/side covers of the wooden crates are removed from the pallet; inside, each speaker is secured, face down, on a rolling base. Once the bottom of the crate is removed, the 220-pound speakers are easily rolled into the listening area. There, the speakers are lifted to their vertical position with the rolling bases still attached. Straps securing the speakers to the bases are then removed, which allows the two speakers to be separated. Once their protective cloth covers are lifted off, the attractively finished products are ready for speaker-wire connection, position adjustment, and playback.

The Berlina RC 9 speakers I received were the same ones I’d heard at CES 2015. The speakers had a high-gloss piano-white finish with white damping rings. This external color, juxtaposed against the black flagstone faceplate holding the pure-diamond and ceramic drivers, made a striking visual appearance.

My listening room is approximately 18' wide and 43' deep, with an 8' ceiling (a little over 6000 cubic feet). The listening space has permanent openings that add few thousand cubic feet of additional space. This room has proven to be very good with low frequencies. Subjectively, the room doesn’t overload with bass, and measured low-frequency response is typically very smooth across the frequency spectrum. We set the Berlina RC 9 speakers in a position along the 18' wall that has worked well for nearly all the speakers that I’ve used. During setup, we could adjust the speakers for improvements and use the supplied Gauder Akustik test-signal CD to adjust bass.