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Floorstanding loudspeaker

Price: 24 000 euro

Manufacturer: Acoustic Consulting

Acoustic Consulting | Gauder&Knapp GbR | Merklingerstrasse 67
71272 Renningen | Germany

tel.: +49 7159 920 161


WWW: Isophon

Text: Wojciech Pacuła
Pictures: Wojciech Pacuła, Isophon
Translation: Krzysztof Kalinkowski

Berlina RC 7 is the top offering of the German company Isophon, founded in 1929. The head of the construction team, Ronald Gauder is very proud of it, because he managed to include certain important solutions in this project. The first one is the way the cabinet is constructed called Rib-Construction. Here the cabinet is composed of thin layers of MDF with a hole milled inside, with washers made from an elastic material. The whole is bolted together from the top and bottom with six metal rods. Mr. Gauder calls those loudspeakers High-Emotion Sound Transducer System, because this rigid, but not “dead” cabinet, is the basis for high class drivers, bought from Accuton, valued by manufacturers of the best loudspeakers like Avalon Acoustics Lumen White, Kharma or Mårten Design just to name a few. And this combination should provide us with “emotions” The tested loudspeakers are big, heavy and will fare best in large rooms. But because they have a way to control the amount of bass, they will also work well in medium sized rooms. The bass-reflex port fires downwards, so the sound is not depending on the distance to the walls, to some extent of course. The sound of the loudspeakers suggests, that it is tuned very low. The amount of the bass can also be adjusted by the spikes. And I should also mention, that you need a powerful amplifier to drive them.

To date we tested::

  • Floorstanding loudspeakers Isophon Vescova


    Discs used for the listening session:

    • Stereo Sound Reference Record. Jazz&Vocal, Stereo Sound, SSRR4, SACD/CD.
    • Tulipany, soundtrack, muz. Daniel Bloom, feat. Leszek Możdżer Trio, Warner Music Poland, 77911, CD.
    • Ann Richards, Ann, Man!, ATCO/Atlantic Records/Warner Music Japan, WPCR-25181, CD.
    • Artur Lesicki Acoustic Harmony, Stone And Ashes, Fonografika, 559040, CD + Master CD-R; review HERE.
    • Charlie Haden &Antonio Forcione, Heartplay, Naim, naimcd098, CD; review HERE.
    • Chris Connor, Chris Connor, Atlantic/Warner Music Japan, WPCR-25163, CD.
    • George Michael, Patience, Sony Music UK, 515402 2, CD.
    • Gerry Mulligan Quartet, Dragonfly, Telarc, CD-83377, CD.
    • Jim Hall, Live!, Horizon/A&M Records/Universal Music Japan, UCCM-9225, CD.
    • Madaleine Peyroux, Bare Bones, Rounder/Universal Music LLC (Japan), UCCU-1188, CD.
    • Milt Jackson Quartet, Statements, Impulse!/Universal Classic&Jazz/Victor Entertainment, UCCI-9088, CD.
    • Savage, Ten Years Ago (Twenty Years Later), Extravaganza Publishing Srl/Klub80, CD002, CD.
    • Savage, Tonight, Extravaganza Publishing Srl/Klub80, CD001, 25th Anniversary Limited Edition, CD; review HERE.
    • Wong San, Feel Like Making Love, Pony Canyon, PCCY-50014, HQCD; review HERE.

    Japanese versions of the discs available on CD Japan.

    Those loudspeakers do not sound well when listened to from the side, without paying attention. They are not made for crocheting or baking, while silky sounds of the voices of Perry Como or Ann Richards are sounding. Those are loudspeakers that can reach us only in one way: when we devote our full attention to them, when we sit down to listen without any things to do, or any thoughts boggling our mind. They resemble a turntable in this aspect – in its case such “casual” listening is also out of the question. So this is the prerequisite to listen to the Isophon – we must concentrate on music. There are also others, like getting the right amplifier and having the right room to set them up. But about those I will tell you later, as they are derivative of the character of those loudspeakers.

    The Berlina RC7 sound with a very focused sound. It is not as live, as dynamically open (in terms of microdynamics mostly), as in loudspeakers with different cross-over frequencies. I mean it differently – no, there is nothing wrong with the dynamics of the loudspeakers. I would even say, that they are very fast, especially in terms they draw the head of the attack, how the information is given about the hit, the blow, the phrase, etc. Here the ceramic transducers, about which I wrote so much good words during the test of the Vescova, sound even better and give us all what they can (and this is by all means not a rule), so we do get: ideal speed, no fuzz in the attack and decay, coherence. A rigid piston, created by the ceramic diaphragm, is just doing what it was made for – move as fast as possible without breakup. That because they are very light and very rigid. And it does not work well each time – I do not know why. But in the Vescova and the Berlina, this speed of the ceramic drivers can be heard very well. However the first impression is just as I told before – the sound seems to be controlled in every possible aspect, even slightly “on hold”, as if placed on a soft cushion, leading each detail of the emission. This is the reason, that you cannot have a “casual” listen. And this all about the engagement of the listener. When we are busy with something else, and the sound will be somewhere aside, then it will be muffled and toned down. And there is nothing we can do about that, no electronics will change it. But when we sit in the middle, even at low volume levels, we get a very well balanced sound, without any drought. This is a direct result of steep cross-over filters, with 50dB/octave slopes. I remember well the sound of the Joseph Audio loudspeakers, which also use steep filters, and the effect was similar. Such way of cutting the frequency range gives some advantages, with the most obvious one being the absolute coherence I wrote about, but it also brings some inherent limitations. But I assume, that music lovers/audiophiles (for me only this combination makes sense) know what they want from an audio system and do it consciously.

    But let us return to the sound. It was the first time, that I did not hear much from the character of ceramic loudspeakers. In this I must agree with the Polish Isophon distributor, Mr. Roger Adamek, who told me that just after the loudspeakers reached him. It is not a “bad” character. Each material sounds in a characteristic way. This can of course be leveled with some other doings, but the pros and cons are “embossed” on a given technology. This is why a ceramic speaker has for me certain assets and equally important drawbacks. The assets: absolute speed and minimal distortion with warmth resulting from that, as a direct derivative of low distortion and not “warmth”. Drawbacks: the sound slightly closed, “intrinsic” so to say. In the tested loudspeakers, and the best Avalon I know, the assets were maximized and the flaws pushed back. But they both are important. The Berlina RC7 sounds like one transducer. Maybe somewhere in the upper midrange you can find a hint, that the midrange driver is a separate entity, but still for five speakers this is a splendid result. The sound is full and incredibly rich in timbres, shades, nuances and details. It is not overly detailed, this is not the case. Listening to music we just get a full picture, nothing is lacking. We get fullness, coherent and holographic. An important element of such sound is the way the treble is presented. Like I said, the sound of the Isophon seems rather warm. And even if this warmth is “natural”, I mean it is created not by adding something, but by the lack of such additions, yet at our homes we will perceive it as warmth. It is exactly the treble, that shows us, that we deal here with something else – there is a lot of information about cymbals, percussion, trumpet or air. Everything has fantastic weight, and the air is not stratospherically thin. The attack of the sound is not accented, and yet better than from most loudspeakers based on paper or polypropylene membranes. It is closest to what you can hear from metal diaphragms. This should not be surprising, because ceramics and metal (especially aluminum) can be formed into very rigid and light structures. Of course there are differences, but those are lesser between the two, than between those and paper and polypropylene. I do not want to generalize anything, that would be an error, but this is how I see it.

    Like I said before, the sound is very coherent. This is its dominant, and everything is subdued to that. This is why it is hard, at first, to split the sound into frequency ranges. I will return to the complete spectrum later, but now let’s talk about the midrange and bass. The latter is strong and full. We could say it is very, very full. This is one of the reasons, that the Berlina will sound better in large or very large rooms. Not that they will be bad in smaller ones – in my, medium sized room, in medium close listening setup, they sounded very noble. Although the jumper regulating the amount of bass was set to -1.5dB and the point of gravity was shifted towards the lower midrange, it was still a very coherent sound. But I think, that the Isophon will feel better is a large, open space. The character of the bass points to very good drivers – similar as was the case with the treble. This was a dense sound. The contrabasses from the discs Jim Hall Live!, Antonio Forcione & Charlie Haden Heartplay and Ann Richards Ann, Man!, although recorded in different times, in different ways, showed the size of the instrument well. Although live it sounds dryer, the belly of the instrument is not so audible, rather some kind of mélange constituted of the belly, the strings and the room response, yet the Isophon showed, that the recording techniques are just as they are, and that we listen to a recording and not a live event. At the same time it was surprising, how accurate the loudspeakers can be, how well they show what is in front of them, meaning the electronics, and how the disc was engineered and recorded, and how little “shit” reaches us. This is a full, vivid, incredibly deep sound, with vast space, dominated with the positive aspects of it. And that not because nothing can be heard, and the loudspeakers impose their character on everything, but because in the black grooves and silver pits and lands there is more than we could have imagined, and the role of a good system is just to extract all of that.

    Because I just returned to my computer with tea (my son bought a splendid Chinese jasmine tea) I read what I just wrote, and I was surprised, how little concrete examples were mentioned. But this is not the first case it happened. Because the Isophon, and a few more devices before them, are loudspeakers that do not ask to be analyzed. Their sound is holistic. Coherent and smooth.

  • There is no harshness or moments, on which we could built a contrapuntal analysis (‘yes’ and ‘no’). They are not ideal, I wrote about that already. But their value lies mostly in the fact, that they fulfill the criteria of high quality loudspeakers with ease: they are communicative; they do not stand between us and the music.

    This is the reason, that in this text I have so little examples taken from the discs listened to, although the list is not shorter as usual with hi-end products. I can only explain myself by saying, that when listening to the Isophon we do not focus on details, but we try to adapt to the new perspective created by them. And this is different than with most other loudspeakers. Only after some time I realized, what they remind me of. They sound similar to loudspeakers standing in an adapted, well damped room. The presentation of the sound stage around us and behind the loudspeakers is very attractive. We hear rather what was recorded and not the room. I do not really know how this was possible, because my room is not damped, it takes part in creation of the sound, but here this was not audible. Its influence could be noticed on the bass, which was shown stronger, and which will fare better in a larger room, but above that we could not hear, that the loudspeakers are playing in a ROOM.

    Those are exceptional products – quick, analytical, saturated and spacious. At the same time slightly warm, sweet, and with agile, not contoured, strong bass. Their presentation is not universal; however, it will have its supporters and opponents. Not all kinds of music sounded in my room in the way I would expect it to. And they are not easy to drive. The last point is easy to explain: the Isophon need a strong, high current, quick amplifier from the top shelf. The beautiful Tenor Audio 175S, I am using currently was fine, but I think, that they would sound better with the amplifier Soulution 710. I like also a lot how the Berlina sounded with Trigon electronics (version 2010) during the Audio Show 2010. Anyway, they need power and refinement. But rather no warming, this is not needed. Like I said, not all my discs sounded in a satisfactory way for me. They were not bad, but with jazz and classical the German loudspeakers were so good, that each departure from that was really noticeable. And now I am talking mostly about electronics – not the whole genre, but the club re-mixes from Depeche Mode single Fragile/Hole To Feed were a bit too “heavy”, too closed. They could use a bit more madness given by other high quality loudspeakers. In this case the coherence and a way of “self-control” of the Isophon (I mean the slight damping) were not working in their favor. But with Jarre and Vollenweider, where the rhythm is less accented, smoother, they sounded much better. The focusing of virtual sources is extremely precise. Without cutting them out of the rest of the event, they are still in the same fluid. Projection of voices, especially the female ones, is above average – they have their shape, they are large.

    The way how the stage is shaped depends, to some extent, on how we bend the loudspeakers. The distributor suggest to have them point directly forward, with no inwards angle, suggesting, that doing it otherwise is an error. I concur with that opinion, but with one modification – in my room it was equally good, or even better, when the angle was very sharp, with the main axes crossing in front of the listener. But the goal was the same – to avoid the tweeters radiating directly at our ears. In that second setting the stage is narrower, but this can be corrected by placing the loudspeakers wider apart, but it was also more precise and had better coherence. Those are not everyman’s loudspeakers, fitting in each room and to each electronics. They sound in a quite characteristic way. So you need to listen to them carefully, at your home – a listening session at the distributor will give only a faint idea, how they will behave in a certain system and room. The way the transducers were integrated in that loudspeaker is incredible, as well as the usage of their assets and covering up their shortcomings. We could use some more openness, some more freedom in the sound, but then we would probably lose some of the coherence and the way everything is glued together into one picture. Beautifully made hi-end loudspeakers.


    The Isophon Berlina RC 7 are large floorstanding loudspeakers in a bass-reflex cabinet. Their dimensions – height 1200mm and depth – 458mm speak for themselves. Like I said – this is a bass-reflex enclosure – in this case the ports, two PVC, with large diameter, are firing downwards. Due to that fact we have to be careful, how high we position the speakers on their spikes.

    All drivers were bought in the German Accuton – this are a 25mm tweeter, 173mm midrange and three 173mm woofers. The inverted dome tweeter (similar to JMLab), made from ceramic sinter, is suspended on a fold made from textile material. From behind the tweeter is covered with a plastic cover, which hosts a large Neodymium magnet. In this case the driver is without ferrofluid – this was noted on a sticker on its back. As option, at extra cost, we can have the loudspeaker equipped with a much better, 20mm diamond diaphragm tweeter. The midrange driver also has a ceramic diaphragm. It is suspended on a double folded, impregnated material, looking similar to the one used in the tweeter. On the surface of the diaphragm we can see two black rings – this is an element of damping the internal resonances – after cutting the rings, the place is sealed with a material resembling rubber. The spider is very solid, cast. The motor is also looking fantastic, made from milled elements from noble steel and having a strong magnet. The mid-top range is sealed with a horizontal shelf and heavily damped. There are actually more horizontal reinforcements in the cabinet – this is the additional function of this division plate. We have five more grommets and one more division shelf, at the bottom of the speaker. Below it there cross-over was placed and mechanically sealed, actually its mid-high range. The low range was placed separately, inside the woofer cabinet. The woofers have a diameter of 173mm each, and are also protected by a mesh placed in front of the fragile membranes, but here the suspension is made from rubber. In the cross-over we see five Intertechnika coils – four with a powder core and one with a solid core – two mass resistors and five electrolytic capacitors, also coming from Intertechnika. We can read in the company materials, that in the other cross-over section we can find noble polypropylene capacitors, gold-silver Mundorf, and ribbon air coils. The loudspeakers are connected using braid wires – the top and middle range with copper and silver plated copper cables, the bass section with thicker copper ones. On the latter there is an inscription “Made by Alfatec”. They do not look very expensive. Between the two cross-over sections there are much better, braid Clearwater cables, looking similar to Kimber. The cross-over frequency was set to 170 and 3400Hz, the midrange driver covers a bigger than usual, and the most important part of the sound spectrum. Unusual is also the way the frequencies are cut – Ronald Gauder chose to use filters with slopes of 50dB/octave. This has its implications on the sound, and I wrote about that.

    But maybe most important is the way, the cabinet was constructed. This is a very costly, time consuming and expensive technology, where vertical, steel rods (six of them here) are placed on especially cut and milled slices – in case of Isophon those are layers of 38mm thick MDF, with 3mm washers from elastic material, covered with silicone. The whole is then compressed together. This is of course not the first enclosure of that kind – let me remind you the, tested in “High Fidelity” Greek loudspeakers Mythos Ligeia, or the Italian Eventus Audio. However it is the first loudspeaker of that kind at Isophon. The front of the tested loudspeakers, also made from MDF, is covered with black varnish with a nice, uneven structure. The loudspeakers have the shape of a lute, they converge to the back, have oval side walls and no classic back plate. This is the reason, that a part of the back was cut away near the bottom of the loudspeaker, where the single wire terminals were placed together with the identification plate. The terminals are the WBT 0765 Midline series. There are also gold plated sockets and a jumpers to set the amount of the bass: -1.5/0/+1.5dB. This system is called Dynamical Bass Control. The loudspeakers are placed on four, very nicely looking, height regulated spikes. The Isophon are manufactured in Germany, in Rennigen, where the company moved in 1997.

    Technical data (according to manufacturer):
    Transducers: woofers - 3 x 173mm, midrange - 1 x 173mm, tweeter - 1 x 25mm
    Type: three-way, bass-reflex
    Cross-over frequencies: 170/3400Hz
    Slope: › 50dB/oct.
    Impedance: 4Ω
    Maximum power (sinus): 290W
    Maximum power (peak): 510W
    Dimensions (HxDxW): 1220 x 230 x 460mm
    Weight: 52kg


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    • Phono preamplifier: RCM Audio Sensor Prelude IC (tested HERE)
    • Cartridges: Air Tight Supreme, tested HERE, Miyajima Laboratory Waza, tested HERE.
    • Preamplifier: Ayon Audio Polaris III with Re-generator Power Supply; version II tested HERE)
    • Power amplifier: Tenor Audio 175S, tested HERE and Soulution 710
    • Integrated amplifier/headphone amplifier: Leben CS300 XS Custom version (reviewed HERE)
    • Loudspeakers: Harpia Acoustics Dobermann (tested HERE)
    • Headphones: Sennheiser HD800, AKG K701, Ultrasone PROLine 2500, Beyerdynamic DT-990 Pro, 600 Ω version (reviewed HERE, HERE, and HERE)
    • Interconnect: CD-preamp: Acrolink Mexcel 7N-DA6300, article HERE), preamp-power amp: Wireworld Platinum Eclipse
    • Speaker cable: Tara Labs Omega Onyx, tested HERE
    • Power cables AC (all equipment): Acrolink Mexcel 7N-PC9300
    • Power conditioning: Gigawatt PF-2 Filtering Power Strip (reviewed HERE)
    • Audio stand Base – under all components
    • Resonance control: Finite Elemente Ceraball under the CD (article HERE)
    • Pro Audio Bono platform under CD