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Audio Consulting Rubanoide 2023 -Long 2.jpg

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What they say ...

Simply put, this is one of the finest loudspeakers money can buy, ... period !

As one reviewer aptly summarized his experience with an AC system :

“For lack of any other way to put it, this is a system that has to

be heard to be believed"


Another comment :

"In its totality, it is not like anything else I have heard before".  


Yet another :

"My entire point of reference just went out the window".


Finally :

"This is a review about the pure listening experience, because an Audio Consulting system can only be heard, not criticized"

Handmade in Switzerland

The Rubanoide Loudspeaker


Rubanoïde ... The name derives from the French word "ruban", which is equivalent to the English ribbon. The "oid" suffix turns it into "ribbon-like" as this new driver operates similarly to the way ribbon speakers work while still being different from a true ribbon. The basic Rubanoïde concept was developed by a French engineer who is nearly 80 years old today. He labored over this project for 20 years because his invention, while deceptively simple in concept, is quite tricky to implement and even more difficult to usher into regular production.

Swiss Audio Consulting has advanced the Rubanoïde development further by working on the wooden frame and other proprietary aspects. The Rubanoide development focused on a single driver with extension to 150 Hz.  Audio Consulting offers a double-driver version, the Dvaijnoy, extending bandwidth to about 100Hz, "allowing for most critical fundamentals in natural instruments and human voices to be reproduced by this new breakthrough driver".

​The Rubanoïde works as a bipole unlike Magnepans, Apogees and most electrostatics. The use of extremely strong magnets achieves the high efficiency with a purely resistive impedance to work well with even single-ended triode amplifiers.

​"Like the big electrostatics (with however far higher efficiency) and good horns, this stunning driver has velocity impedance air coupling unlike the pressure coupling of almost all other drivers. The efficiency in energy transfer from the membrane to the air is such that even for higher frequencies, the sound is more realistic and dynamic than for example a Raven R3 ribbon. This is particularly interesting as the Raven features a 30mgr moving mass while the Rubanoïde has a 30gr moving mass.

Features for the Rubanoide 2.0 include 98 dB efficiency from 150Hz to 20,000Hz. The Bass unit developed in collaboration with Sven Boenicke, deploys a 12" custom woofer and extends the system's response down to 33Hz.

The Rubanoide 2.0 is now extended at both frequency extremes via Audio Consulting's new 25 cm Ribbon Supertweeter, and can be further extended via pair of Subwoofers, resulting in a truly awe-inspiring system.


More about the Rubanoide 2.0 :

  • Historical Roots :


  • The speaker has it roots in the history of a very original loudspeaker driver when Paul Paddock and Ben Stutz launched the Linaeum driver in 1983.

  • John Eargle in his “Loudspeaker Handbook”, provided some description and details of the physical set up of the Linaeum, on page 394.

  • Going back as early as February 1927, we find first traces of such a type of loudspeaker by Clyde J. Fitch in the Magazine “Radio News”. It was introduced as a “three foot roll type speaker” with “excellent tone quality”. That was to show how old the basic idea of a line source/wave bending driver is.

  • The German word “Biegewellenstrahler”, literally “radiator of bended waves” explains part of its behavior, while some piston movements also have to be considered when we try to explain its physics.

  • Audio Consulting’s version of this type of driver : 

  • Audio Consulting started research work on the Rubanoide (from the French language, meaning “similar to a Ribbon”) in 2005.


  • The major task was to avoid any type of plastic for the membrane’s material (which was the case for all Linaeum drivers) and achieve a driver of at least 40cm in height. If assembling the magnetic set up is far from being trivial, if not to say even dangerous because of the magnetic force of the magnets used, the real challenge turned out to be the paper for the membrane.

  • Changes in the atmosphere’s moisture content may easily lead to blocking the moving coil within the air gap and thus totally prevent the speaker from working, switching it to “airplane mode”.

  • While plastic membranes of any sort where excluded for sonic reasons, we had to find the right paper that had to be completely dimensionally stable when facing important changes in the air’s humidity content. After two years of experimenting many types of paper from many parts of the world, we found such a special item. We keep it confidential for the time being, but may say that it is 100% dimensionally stable even when laid into plain water. By this point, we found ourselves with a functioning driver by the end of 2007.

  • We then had to find out in which part of the audio spectrum this driver will perform best. While the efficiency of close to 100dB/w/m for a single driver was very promising for its use as a near-to-full-range-driver, the question arose of how much it may play as a full range driver? After many hours of testing and listening we started using the single element Rubanoide with a 12dB/oct crossover at 250 Hz, this whilst the Rubanoide Dvaijnoy (double Rubanoide) is being used from 120 Hz also at 12 dB/oct.

  • The Rubanoide driver is in essence a dipole driver with the advantages of dipole drivers, but with much higher efficiency than most other dipole drivers. Even a single element of the Rubanoide driver is already close to a line source, ... whilst installing one atop the other in a pair, definitely is a line source.

  • Efficiency around 100dB/w/m, and speed coupling to the air’s impedance, allow for micro and macro dynamics encountered normally only with horn drivers. This, however, with the advantage of needing only one driver from 120Hz, resp. 250Hz to the higher end of the audio spectrum.

  • If properly set up in the listening room, it also provides a sound stage of incredible realism.

  • We have developed three commercial products using the Rubanoide driver:

    1. The “Rubanoide”, featuring one Rubanoide speaker element atop a modified transmission line speaker using a 12” paper cone driver. The efficiencies of both drivers are similar, allowing for a speaker basedm on a 12dB/oct crossover with in house made crossover elements.

    2. The “Rubanoide Dvaijnoy”, featuring two Rubanoide drivers, one atop the other and designed with its speaker-based crossover set at 120 Hz. Several high-end active sub woofers have been used with the Dvaijnoy and very good results were achieved in doing so.

    3. The “Rubanoide three Way Speaker”, that includes two Rubanoide mid-high drivers per side, as well as one Rubabass 2 low frequency dipole driver for frequencies below 120 Hz. The latter is technologically similar to the Rubanoide medium drivers, but features about double the paper surface than the Rubanoide, which is equivalent to about 2.5 times the surface of a 15” driver per side.

  • We also decided to add a super tweeter for frequencies above 12 KHz. After another year of R&D, we ended up using a dipolar design.


  • A few thoughts about the Rubanoide’s sound : 

  • With its resonance frequency set at 26 Hz, the Rubanoide driver is much more a full range driver when we consider its sound qualities over the entire bandwidth.

  • The neutrality, resolution, dynamics and life like character of the Rubanoide are one of its kind ... Unique. The absence of any spider, and the use of a suspension that is very different from any suspension found in classical loudspeakers are part of the explanation of this unique driver’s features.

  • We also have to realise that with the Rubanoide, the vibrational energy is transmitted to the air in “speed” mode, much more than in “pressure” mode.

  • The German word “Biegewellenstrahler”, or “radiation of curved waves” explains, in part, the Rubanoide’s physical behaviour. In fact, this is very similar to a horn that transforms the pressure mode of the compression driver to a speed mode at the flare of the horn in order to meet the air’s impedance and most efficient transfer of energy.

  • One also has to keep in mind that the active surface on the front side of a Rubanoide is 0.12 square meters, roughly equivalent to the surface of four 8-inch drivers.

  • Also, the big difference between the Rubanoide and a horn system would be the Rubanoide’s now we have the equivalent of another four 8-inch drivers coupling to air in the opposite polarity.

  • Add a 100dB/w/m efficiency, and one gets a very unique driver.


  • All Rubanoide based speakers we offer are absolutely unique systems :


  • The 2023 Rubanoide 2.0 version :  Starting in 2019, we developed a new Rubanoide mid-range driver.

    • It now handles more power, and plays at lower frequencies, in fact as low as 100 Hz.

    • Resonance frequency is around 11 Hz which is extremely low for a mid-range driver.

    • This allows it to play far away from its always disturbing resonance frequency.

    • New crossover parts also are part of the change:

      • Toroidal filter chokes

      • Custom made oil-film capacitors

      • Custom made silver-electrode capacitors

      • The dipolar AMT tweeter is now included ...

      • ...and makes the Rubanoide 2.0 a fully- fledged three way system.



RUBANOIDE 2.0  3-Way

$ 105,000   / Pair


Frequency Range

33-20'000 Hz




@ 150 Hz


8 ohms


H 140 cm, W 35 cm, D 50 cm


55 Kg each

Audio Consulting Rubanoide 2023 - Small.jpg






The “Rubanoide Dvaijnoy”, features two Rubanoide drivers, one atop the other and designed with its speaker-based crossover set at 120 Hz.


Several high-end active sub woofers have been used with the Dvaijnoy and very good results were achieved in doing so. We recommend the Grimm Audio SB1.


Also required to complete the system is a high quality audiophile level Low-Pass Crossover for the Subwoofer. For this purpose, we recommend the German-made active, but importantly, "Analog" SPL Crossover. 



The Grimm SB1 with ‘DMF’ is a technological marvel. By applying ‘Digital Motional Feedback’, a control technology from the renowned Dutch high-tech industry, it became possible to achieve exceptionally low levels of distortion and full dynamic control. With an SB1 added for the bass frequencies, the LS1 system offers low distortion over the full audio band and redefines the term ‘transparency’. This is bass control like you’ve never experienced before.


“Digital Motional Feedback offers bass control like you’ve never experienced before.”

At frequencies below 100 Hz loudspeaker drivers need to move a vast amount of air and therefore have high excursion levels, while also the fundamental resonance – which is present in any loudspeaker – induces unwanted delayed effects. The result is that all conventional loudspeakers exhibit a rising distortion in the bass region with additional “thickening” of the bass by the resonance.


In electronics, feedback is used to minimise distortion. To apply feedback in electro-mechanical systems like an active loudspeaker, an acceleration sensor needs to be mounted on the cone to monitor its motions. This so called “Motional Feedback” technology has been presented a few times before in history but the precision and control as found in the Grimm Audio SB1 is unique. By adding smart digital processing and current drive, the low distortion of the already high-performance aluminum woofer is further reduced by as much as 30 dB, solving all problems that are related to low frequency resonances and distortion


" ... As our bass improves to move away from the ‘drone-cone’ effect, so does the rest of our bandwidth benefit. There’s less haze overlaying it, less blur, bloat and noise. Some swamp drains. Improve what happens down low and what’s higher up can’t help but improve with it. As below ... so above. The SB1 are that sort of sub. They raise our listening IQ. We hear more and do so more easily, in areas that have nothing to do with bass though of course the bass is included. (…) Because of it one needn’t crank the volume. Excellent visibility starts already at the bottom of its range. Perhaps that’s actually the biggest benefit of all? "  Srajan Ebaen | 6Moons | September 2021

The SB1 is not just the perfect companion for an LS1be system. It also brings your 3rd party home cinema or active crossover system to high levels of performance. Reviewer Ruud Jonker of the Dutch magazine Music Emotion tunes his crossover ... and is impressed :


" To tempt the Gods I started with Liszt’s Prelude & Fugue on the theme BACH, performed by Felix Hell. The gigantic and palpable power of the sound that the small SB1s produced struck me. (…) What the SB1s are doing here is masterful. That enormous amount of acoustic energy is produced in great quality. No thickening when the frequencies drop and no fuzziness, smearing and loss of tonality. There is absolutely no whipping undefined fog of sound. On lesser systems, such a church organ often turns into a vague something, where all kinds of tones intertwine and form a mess ... Above all, the SB1s fit into a real world scenario. In today’s time, hi-fi should be as compact as possible and not be a disturbing factor in the living environment. For that setting, there is no solution that is more useful and elegant than the SB1 ... Oh Lord, give me an SB1 ! ”  Ruud Jonker | Music Emotion | September 2021


$ 118,500   / Pair


$ 12,800   / Pair

Recommended / Required Component


[ Active / Analog ]

$ 3,000




Frequency Range

100-20'000 Hz



High Pass Dvaijnoy ​Crossover

@ 120 Hz


4 ohms


H 145 cm, W 55 cm, D 32 cm


36 Kg each


10" ULF Driver

Digital motional feedback for 30 dB less distortion

Linear response from 500 Hz down to 20 Hz

DSP controlled frequency curve

Modified woofer and 700W class D amplifier

Dimensions : H 21.3 cm x W 35.8 cm x D 34 cm

11 Kg each







The Rubanoide 3.0 is a three way speaker, that includes two Rubanoide medium drivers per side, as well as one Rubabass 2 low frequency dipole driver for frequencies below 120 Hz.


The latter is technologically similar to the Rubanoide medium drivers, but features about double the Rubanoide 2.0's paper surface, which is equivalent to about 2.5 times the surface of a 15” driver per side.


Here again, we decided to add a super tweeter for frequencies above 12 KHz. After another year of R&D, we ended up using a dipolar design.


RUBANOIDE 3.0  3-Way

$ 300,000   / Pair



Frequency Range

30-20'000 Hz


Over 96dB/w/m

High Pass AMT Supertweeter ​Crossover

@ 12 kHz

High Pass Dvaijnoy ​Crossover

@ 300 Hz

Low Pass Rubabass ​Crossover

@ 300 Hz

Crossover Components

Silver wire coils and transformers

Silver capacitors


4 ohms


H 195 cm, W 65 cm, D 80 cm


98 Kg each

Constantin Gregg-Saad with Audio Consulting Reference System
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