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The e-mail: "My name is Jean-Michel Maumont, financial partner of Marc Henry and Hugues Borsarello in Audiosophie sarl. Marc and Hugues are the creators of the fully horn-loaded 3-way Grande Castine speakers you announced in the news section of 6moons last Friday on the recommendation of our friend Franck Tchang. We fully agree with Franck that France will be a small market for this kind of speaker and that we must rely basically on export and get the word out to an international audience. We would like to invite you to visit us in Paris and hear our speaker."


This had all the makings for one of our quite popular RoadTours. And guilty as charged, I had indeed posted a brief news announcement after Franck Tchang of Acoustic System Int. had pointed me at the French website and intimated that a closer encounter would be proposed in due course.


The last such invite had whisked me off to the South of France and Ocellia and PHY HP. How often does the opportunity arise to audition an ambitious new full-range hornspeaker not under the usually quite compromised show conditions but as set up in the designers' very own space and system?


All I knew at that point was based on my own news post. And that of course was culled from a then still rather rudimentary website:


"Musique Concrete in Paris by Hugue Borsarello and Marco Henry makes an ultra-efficient hornspeaker in the 108dB range called the La Grande Castine, a physically time-aligned fully hornloaded 3-way about which the website at present offers scant detail while the photo gallery is already better stocked.


"With talk of a possible visit to Paris in the air, we might have a bit more information to add by next month. Otherwise we'll have to wait for the website to begin listing more details about the specific design goals, drivers and implementation." Now I must add that unexpected encounters with big horn speakers have benignly 'interfered' with our lives before.

Reviewing Avantgarde Acoustic's Duo had occurred at the onset of my audio reviewing career and their subsequent acquisition represented my first truly serious foray into an ambitious hifi speaker and a commitment to delve deeply. Years later, a 6moons reader invited me to Limassol in Cyprus to experience his massive 6-way hornspeaker installation. Being introduced to the island at the precise time when we had plans to leave the US seemed like a sign. Going with the flow, we duly relocated to the Med a few months later. When the owner of those horns moved to Switzerland and invited us to visit him a few years later, the spectacular scenery around his residence right on Lake Geneva became a motivator for our subsequent move to Chardonne.



In short, hornspeakers have seemingly exerted strange influences on our lives to often become harbingers of exciting future adventures. Without any designs other than accepting a harmless audiophile invitation, I nonetheless marked this a special occasion. I prefer high-sensitivity speakers to all others but achieving 100dB+ values without horns is nearly impossible - and horns come with their own challenges, not the least of which is size when hornloading is to extend into the low bass; and specific colorations.


The name Grande Castine mirrors the speaker's development in Brittan'y Saint Cast Le Guildo near the famous Le Mont St. Michel. St. Cast's female inhabitants were known as Castines hence this dame became the Grande Castine. For specifics on a precursor to the latest iteration, the active crossover for the bass had been 18dB @ 250Hz and the passive networks for the upper drivers 6dB @ 300Hz and 6dB @ 4000Hz while the horn geometries were based on Jean Michel Le Cleach formulae.
At that time, the German tweeter had been a BMS 4540ND unit, making it a 500g 1-inch throat neodymium-powered polyester diaphragm compression driver with 114dB sensitivity, response to 30kHz, 8- or 16-ohm impedance and a 1.5" voice coil on a Kapton former inside a 2.2 Tesla magnetic flux field.

The 4.73kg Radian 950PB was a 2-inch exit neodymium-powered aluminum diaphragm compression driver with Mylar suspension. Its usable response is from 500Hz to 20kHz, sensitivity 111dB, impedance 8 or 16 ohms. The 4" voice coil operates inside a 19,000 gauss magnetic flux field.



The woofers were from Altec's 16-inch 515G Series which incorporated their largest 3.74kg Ferrite magnet structure, an edge-wound aluminum flat wire voice coil, a light cone assembly, low-distortion cloth suspension and a die-cast aluminum frame. The 30lbs 515-16G had an 11.3-ohm voice coil, a free air resonance at 37Hz, a BL factor of 25.1, a magnetic flux density of 15,000 gauss and, depending on chosen horn, a sensitivity from 103dB to 108dB.

The next communication from Jean-Michel Maumont arrived a day after the Paris show where the Grande Castine had been on static display. Relative to comments I'd gotten from Franck Tchang after he had actually sampled the speakers at their common dealer show room Connemara and reported the sound to be far from satisfactory, Jean-Michel explained that "Franck came for a very quick visit during the installation. This auditorium is quite small and the  speakers were far too close to the side and rear walls. We are currently working on an L-pad for the crossover as well as a special back chamber for the woofers to make for easier adaptation to  smaller rooms. The earlier info on the drivers we used is no longer correct. We extensively tested every single transducer on the market and no longer use the BMS, Radian or Altec drivers but switched to modified European pro drivers. The new woofer was from-the-ground developed just for us and sports a lighter cone, stronger magnet and more sophisticated technology.


"The bass horn only covers the 80-300Hz range. The first two octaves are  handled by a separate powered planar subwoofer. Franck  came at the beginning of the installation when we'd been out of the auditorium and Connemara owner Edgar Morineau was not yet fully aware of the adjustments of the electronic filter on this sub-bass channel. We also had some poor integration between lower and upper horn caused by the proximity of side and rear walls with our open rear bass horn. That never was the case in larger rooms. Now we are working on experiments to partially or totally enclose the 2 x 15"  woofers without losing the openness of the sound—one of the strengths  of this design—to facilitate the integration with smaller rooms. Several very qualified persons have already visited us at Connemara and very much appreciated the sound despite the room's  limitation for this kind of speaker - Dominique Mafrand aka Pierre Andre Viollet, reviewer of Prestige Audio Video magazine—"really amazing, sincerely"—and Jean-Marie Piel, Chief Editor of Diapason magazine - "the only horn  speaker I know I could live with."


"Our preference not to communicate the make of our new pro drivers stems from the fact that the moment one reveals their identity, people immediately conclude they can predict the sound from previous encounters with those drivers in very different speakers. For the 2-incher, we modify the volume of its stock front compression chamber to adjust its low-pass function while our rear-chamber modifications create a natural high-pass filter. With the 1-inch tweeter unit, the phase plug connects directly to the horn flare and we decompress the rear chamber. We also bypass the stock connectors."


With an original on-site audition in November likely delayed due to ongoing fine-tuning work in the field, we shall revisit this product launch when data have been finalized and I've traveled to Paris...

Musique Concrete website