Translation: Krzysztof Kalinkowski

I do not know the loudspeakers from the brand Isophon. I know, I know, confessing to something like this might seem somewhat unprofessional, but it is better to set everything straight from the beginning. I know them only from Munich shows and tests. I never heard any of the loudspeakers from that German manufacturer in controlled environment, meaning in my or in a known system. So in some way it is true that I did not do my homework. During my studies, on the first seminar from psychology said one thing, that I remembered well and try to apply it in my life: no specialist is an oracle. There is no way for that, and the earlier we accept that, the better for us. This was about another specialty than expert audio journalism (and this is my area), but it is equally true here and now. Please consider this: is it possible to listen to every device in the world? This is physically impossible, because physics (I am talking about the one that is valid now and not about quantum physics) states that it is impossible to occupy two different places in space. And one would need to listen to a dozen of products at the same time, at least, to be able to tell: I heard everything. If somebody from your environment or from your beloved audio magazine says that then he is lying.

And I simply did not have the opportunity to test the Isophon. In “Audio” the loudspeakers are traditionally handled by Andrzej Kisiel, and in HFOL it just did not happen. Maybe it should be like that. The first product of that company that we will test is also a novelty for the manufacturer, as we deal here with loudspeakers that do not have drivers with classic paper, polypropylene, metal or silk diaphragms but ones made from ceramics. This is not a one time happening from Isophon, but a part of a bigger whole: Vescova opens the line of loudspeakers equipped in such drivers, with the models Cassiano and Arabba positioned higher. This is a two-and-a-half construction equipped in drivers from the German Accuton, used also in the ultra-expensive models of the American company Avalon Acoustics, that made it famous. Why ceramics is used? We feel intuitively that this delicate and fragile material looks great in expensive porcelain, but not necessarily in speakers. But as usual this is only a part of the truth. It is true that ceramics is very fragile and delicate as they are very prone for impact. This makes it crack like an eggshell. Hence the protective meshes in front of the drivers. On the other hand they are very rigid and realize – probably in the best possible way – the idea of the rigid piston that every diaphragm should be. In addition the parasitic vibration is damped inside the frequency range – problems for these drivers are the peaks outside of it. It is also known, that their linearity is satisfactory only in very narrow interval. This is responsible for another characteristic of that kind of speakers – very steep filters are needed in the cross-over. Isophon is not an exception here, but probably reached the extreme – in the whole speaker line the filters drop like a stone in the water – 50dB/octave. Such steep analog filters in loudspeakers are an absolute rarity and big experience is needed to not destroy anything. However steep filters bring not only advantages, but also some uninteresting phase behavior and troublesome energy arrangement. But engineers always have to make choices. Here we get absolutely rigid diaphragms at the cost of absolutely steep filters.

I did mention Avalon – and that was on purpose. This is a very renowned company, and I heard its speakers many times in many systems, on many shows, etc. And I have a problem with them: I never heard that what all reviews in the world speak about, the sound was always dull, flat, aggressive or too warm. Not even one speaker of that company sounded like I thought it should. I think that there is potential in them, I want to believe in that, but nobody from my acquaintances was able to get it out of them. And I would probably let it go and not care anymore about Avalon, if not for the ecstatic statements about those speakers by three independent sources I value: Roy Gregory, editor in chief “HI-Fi Plus”, Martin Colloms, editor of “HIFICritic”, and “Hi-Fi News” , author of the book High Performance Loudspeakers and Winston Ma, owner of the record company First Impression Music (photographs of his previous system HERE, now he uses the top model Sentinel). All the mentioned gentlemen are professionals with long expertise, trustworthy and use those constructions for their pleasure and as tools. This is food for thought, because… nobody is an oracle and I can be wrong.

On one hand I approached the test with a blank page – I did not know the brand, on the other with the burden of previously bad experiences with ceramics in hi-end loudspeakers (I tested some time ago the loudspeakers Swar from Kustagon/Amparo that I liked, but this is only a fore room of what we are talking about). The uninteresting listening to another legend of ceramics, the Dutch company Kharma also did not help the case. Still I was very interested in this listening test, because for the first time I could confront the show listening, heard opinions, etc, with what I heard in my own system. And one thing is clear from the very beginning: loudspeakers with ceramic drivers are very picky when it comes to the choice of the cooperating equipment; require long positioning and – most importantly – acceptation of some limitations. If the latter are a barrier we can cross then it is fine – we get a package of characteristics not found anywhere else. Or maybe they are, but I did not hear them anywhere else. I will talk about the sound in a moment, now something about the first two things. The system first. I think that the loudspeakers absolutely need a clean, quick solid-state amplifier. I did not have access to a very powerful tube, like the Manley Neo-Classic 250, tested by me some time ago, but knowing its kind of sounding, I can tell, that it is probably the wrong way to go. This is partially supported by Colloms, who drives his Eidolon Diamond by solid-state amplifiers from Conrad-Johnson, the Premier 350. The system of Winston Ma has very powerful tube power amplifiers, but the Isophon need something else. In my system with the Luxman M-800A http://highfidelity.pl/!ev/artykuly/19_11_2007/luxman1.html it was splendid, first of all due to the brilliant current efficiency of this amplifier, but the more power the better.
The second thing is the setup of the speakers. The tested Isophon loudspeakers are a two-and-a-half way design, with a ceramic dome tweeter on top and two identical mid-woofers in a 1 and ½ configuration, where one of the drivers works in a closed cabinet with the tweeter and the second one, transmitting only a part of the bass spectrum is vented with a bass-reflex port. Isophon placed it on the bottom of the cabinet, making the coupling with a hard surface (the floor) a constant, what should ease the setup in some way. This is deceiving, nothing is as easy as it seems. The Vescova sounds with a strong, energetic bass and needs quite a distance from the back wall. It is advisable to place them in a big room. I handled the bass in my room by plugging the bass-reflex with a sponge (what brought also additional advantages, but about that in a moment). Equally important to the distance from the back wall turned out to be the distance between the loudspeakers – the Isophon like space. It is worthwhile to place them quite wide apart. In my system they were initially placed on the inside of the Dobermann Harpia Acoustics http://highfidelity.pl/!ev/artykuly/18_09_2007/harpia1.html that I use on a daily basis, and that are placed wide apart, but I quickly realized that on one side I have to place the German loudspeaker on the outside. One more thing – tow-in. The distributor tells, that it is best to have them set straight forward. In my system they sounded better towed-in, but not pointing at the ears. So one has to experiment.


So prepared I listened, quietly, almost all the time. Almost all the time, because it was the first time I heard what is the hype about ceramic drivers, and for the first time I heard elements of the sound that do not exist in reproduction anywhere else, maybe except systems like the Wing Ancient Audio http://highfidelity.pl/!ev/artykuly/22_02_2008/aa1.html . Sitting in the shadow of those loudspeakers we immediately lose ourselves in their incredibly clean sound. I have no doubt that the distortion of those speakers, and probably the ceramic drivers in general, are at a really low level. This gave an incredibly precise attack of the instruments and brilliant reverb. Everything had a perfect time of start and sustain. Without a trace of brightening. This is really a paradox, as usually precision is associated with slight underlining of the attack, and sometimes hardening of the timbre and sharpness. This is also the easiest way to simulate such a sound. But then it is in 100% rubbish. Only here it can be heard, that all known to me dynamic speakers have a slightly washed-out attack. Although the best ones, like the mentioned Wings or my Dobermann can pull themselves together immediately and play with beautiful sound, but even they cannot sound that coherent, with such a – I don’t know how to describe it best – elegant transmission. Compared to the Isophon all loudspeakers have a kind of mist, dust just before the sound, in the moment it is born. This is just a moment, but now, having a reference point I hear that happening. Only in the best electrostatic (Quad) and magnetostatic (Magnepan) loudspeakers this effect was not present. Metal loudspeakers, when well designed, handle this very good – that is the case in the Harpia loudspeakers, but also in Von Schweikert, Sonics by Joachim Gerhard, Sonus Faber and others. Only here we can hear that it can be bettered.

Associated with this is the absolutely brilliant drawing of the events on the stage. I could not resist mentioning this now. Every instrument, element, dust even, are shown in a beautiful surrounding, with incredibly well reproduced reverb. Very difficult material in that aspect from the disc Guillame Du Fay Diabolus In Musica (Antoine Guerber, Alpha 908, CD) was shown with a breathtaking naturality (of course an imagined one – I don’t know that recording room). And this without any aggression, without brightening, in a natural, loose way. Even dignified, one could say. Also small ensembles like from the discs Jacka Johnson Sleep Through The Static (Brusch Records, 756055, CD) or Old Friends-New Roads Allana Taylora (Stockfisch, SFR 357.6047.2, CD) sound brilliant in that aspect. Every time I changed the disc in a few seconds the recording room could be “recognized”, or at least the kind of reverb that was used for the spacializing of the sound. With acoustic playing, like in the case of jazz, the side walls are heard very well, also the back wall is heard, that usually flows out or is just being marked. Here it does not matter if this is a intimate playing of the Montgomery brothers on the disc Groove Yard (Riverside/JVC, JVCXR-0018-2, XRCD), or strong vigorous sound of the disc Sonny Rollins Trio Sonny Rollins/Brass (Verve [Japan], POCJ-2729, CD), every time the room, the space were shown almost perfectly. But… there is something in this, that I think is inherent to ceramic speakers and (and maybe first of all) steep filters: all rooms presented by the Isophon have the same cubature. This means, that when we have a church then it can be hear that this is the kind of interior we deal with, the kinds of reverbs, delays are shown perfectly, it can be heard that the ceiling is somewhere far to the top. Small rooms, like the one from the disc Heartplay of the duo Charlie Haden & Antonio Forcione (Naim, CD098, CD) is also shown as that, with close reflections, damped reverb, etc. But in both cases everything is a bit smaller than on other good speakers, the sound is more intimate, there is no such opening like in the Doberman, there is no such “kick”, etc. It is heard as if everything would be slightly damped. I called upon this example some time ago, probably while reviewing the ART Stiletto 6, but after switching to the Isophon from speakers like the KEF Reference 203/2 http://highfidelity.pl/!ev/artykuly/20_12_2007/kef1.html everything is heard as if we would go from the “live” room to a demo-room in an audio shop – everything stands down, everything is closer and more palpable. But the ease and “breathing room” disappears.

Those are the firs and probably the most important characteristics of those loudspeakers. The tonal balance is completely different from the one that could be expected judging on the used drivers, but I think that this will not be the deciding factor in perception of the Isophon, but rather the earlier mentioned elements will. Analyzing the energy in every frequency range the impression cannot be resisted, that the white diaphragms of the speakers, suggesting chilling and hardness deceive us deliberately. The Isophone sound with a very well arranged, slightly warmed sound. Everything has its place and time. It is similar with the best metal membranes, where the early representatives had a harsh and brightened timbre, and the sound was nervous and tickling. The newest units, with SEAS-a in the front row, well applied, sound creamy and warm. I think, that in their case, similar to the Isophon, the minimized distortion finally pays dividend. This is perceived as a slight warming of the sound, and in reality this is just getting rid of the errors and dirt from the sound. Those were most of the time the reasons for a sharp and bright sound, and not the “character” of the drivers. Here, just like with metal, the idea of the speaker being an ideal piston, is so close to the assumptions, that we get all that is best in them without their shortcomings. The problem of the filters still remains, filters that like in the Isophon, influence dynamics and energy of the sound. But about that in a moment – now some more words about timbre.

The second part of the sound spectrum is strong and dynamic. In my room I had to use the foam plugs to integrate this sub-range with the others. Without those the loudspeakers played with a splendidly saturated, “live” bass, that sometimes played a bit loose from the main events. I do not know exactly where the cross-over frequency is located, but probably somewhere around 35-45Hz, because the low passages of the contrabass, an instrument with the basic tone at 41.20Hz, sounded in a moment softer, as if slightly muted by the musician. In general (I should have done it earlier, but it is never too late) all my remarks are relative to a certain absolute reference, this is true classy hi-end, and they should be evaluated in that context. Anyway, when a sound came lower, the bass guitar and piano (a concert Steinway goes down to 27.50 Hz) everything go boosted. After placing the plugs the energy of the lowest sub-range was smaller and the linearity improved. There was no longer the impression of loudspeakers and a subwoofer playing. The coherence of the sound also improved. Maybe in a short listening session the, brilliant on the bass, disc Violator Depeche Mode (Mute, DMCD7, Collectors Edition, SACD/CD + DVD-A) will not be that exciting with the plugs. But let us listen longer, and we will come to the conclusion, that there was something wrong in the timbre earlier, and that THIS is the true playing, as there is deep bass (the Isophon go far down) and control. This last characteristic is actually true regardless of the treatment of the bass-reflex, the start and the stop of every sound are heard perfectly, without prolongation, without droning, etc. Saturation, fullness, etc – A grade. The midrange is a derivative of the transition between the treble and the bass, meaning that it ideally fits in the philosophy of the sound. It is strong, full, saturated, and slightly warm. This is no “warming” but the effect of the creamy, a bit withdrawn treble. So we do not have the vocals pushed out to the front, but the feeling of coherent sound. Actually with the vocals the case is so, that despite perceiving the sound as aggression free and thus a bit warmer than usual, the voices are reproduced quite far away. I do not claim that they are withdrawn, but they do not have such palpable shape like with the Dobermann and totally do not for the boosted way of sound like from the mentioned Stiletto 6.

I think that this has common roots with the slightly limited resolution of these speakers. Please understand me well: those are splendid speakers, in some way perfect in reproducing the attack and reverb, all elements are better visualized (in a warm tonality, what is ultra-rare) than in most dynamic speakers on the planet, but when we talk about the “insides” of the sound then I have the impression, that this element is a bit homogenized. Other expensive loudspeakers, with metal and paper drivers (in my opinion there are not many of the latter) can show more facture, if there is dirt then it will be shown, if there is flatness then it is played like that. The combination of the characteristics described above allows the Isophon to sound just nice. I do not want to be treated as a masochist, I like it when the music sounds nice, listening to music should be a pleasure, should be an itelectual and emotional entertainment, but the German loudspeakers (maybe it is about the drivers? Or filters?) play everything on a similar level, the emotional temperature is similar. In most cases this is good news, because connecting them to a solid-state poweramp, needed for the bass control, we do not have to care about dry, “transistor” sound. I just would avoid to artificially warm the sound of an amplifier. With the Isophon this does not have any meaning, because everything starts to “live”. An example for me that the German constructions are a kind of musical instruments, playing like a Stradivarius, in a warm, nice tonal balance, was an experiment not done with stereo but with home cinema. I know that this is not man-like to write in such a magazine about cinema, but I will not hide the fact that I watch many DVDs. From the time I bought the plasma screen (I will write about that in near future) I lost my reason and I buy and watch, buy and watch. From the side of the vision everything is kosher, but from the audio side it is upside down, at least looking from the perspective of a home theater fans. I always play sound in two channels, stereo only. Normally the CD is connected to the preamp and the latter to the power amplifier. In the home theater it is different: my Arcam Solo Movie 5.1, is directly connected to the power amplifier’s second input by means of the pre-out sockets. The sound is very correct, detailed, a bit “cinematic” by the emphasized dynamics, but at the same time a bit dry. I forgive that, because this allows for a simple sound path and eases the handling. In this setting, the Isophon sounded much better, more coherent and fuller than the Dobermann. The latter are very sensitive for dryness and brightening, that they do not tolerate, “spitting” it out in the first seconds of playing. The German loudspeakers were different – they filled in the gaps, added the sound “meaning” and “importance”. Listening to them was really great! The class of the source was know immediately, we knew that this is no hi-end unit, that this is a so-so radio, but there was no pain and despair.

I wrote a lot, but I could not get around that. The Isophon Vescova are the first loudspeakers with ceramic drivers that I really liked. They showed the pros and cons of that technology very well. Some of their assets are put on such a high level, that they are hard to be repeated elsewhere, and if such focusing and thorough sound would be repeated in other loudspeakers we would be dangerously close to the ideal. Other elements were not so outstanding, but still they don’t fall below a certain, very high level. Those are slightly warm, but not warmed – I know how this sounds, but I hope you read the whole test and know what I have in mind – sounding speakers, with splendid bass. You have to work on the latter placing the speakers properly, and with other techniques, but it is worth the effort. I was not expecting, that the first meeting with ceramics in my home and at the same time first loudspeakers from Isophon I tested would be so satisfactory.


The loudspeakers of the company Isophon were constructed by Dr. Ronald Gauder. Those are two-and-a-half way floorstanders, with two mid-woofers from Accuton with 150mm diameter each (diaphragm + suspension), with the diaphragms made from ceramic composite. The same material was used for the inverted dome tweeter (inverted like in Focala) with 25mm diameter. As an option the speakers can be ordered with a diamond tweeter (just like in the case of Avalon speakers, and at extra cost). The drivers are filtered with very steep filters with a slope of 50dB/octave. Extremely worked out cross-over is to be found in the upper part of the cabinet. Separated in two parts – mid-bass and treble section it is screwed to reinforcements from MDF (and the treble section additionally to plywood). Those are very complicated filters, with many coils (and all of them, except for the biggest one are air coils) and polypropylene and electrolyte capacitors. Most elements come from the companies BLM and Inter-Technik. The speaker below the tweeter is placed in a sealed chamber and is filtered from below only with the volume of the chamber. The lower speaker is cut from the top at 180Hz and works in a bass-reflex vented chamber with the outlet pointing down. This allows controlling the amount of bass coming from that side of the driver, but I think it is also a consequence of the shape of the cabinet. It has an unusual shape of a “boat” with round sides and a sharp back. The enclosure from shaped plywood (sides) is made as a “sandwich” with filling in the form of sand. The front, top and bottom are made from MDF. So the whole is very rigid and heavy. It is damped with loose, not compacted artificial wool. The speakers in the higher section are connected with cord cables – one branch is from copper and the second, thinner, in blue isolation is from silver plated copper. The speaker in the bottom chamber is connected by a cable looking exactly like cables from Kimber Kable, but with red and black isolation, and I don’t know that model. On the bottom single wire terminals from WBT are located, what is not really convenient and asks for extra skills to operate with thick cables. Next to the bass reflex cramps for controlling the loudspeaker timbre are visible, but they were not active in the tested model. Different finishes are available 0 the tested speakers were in piano varnish – very nice but very impractical.

Technical data (according to manufacturer):
Maximum power (sinus/impulse): 220/410W
Cross-over frequencies: 180/3200Hz
Nominal impedance:
Dimensions: (HxWxD) 1100 x 210 x 410mm
Weight: 30kg


Price: 29 000 zł

Distribution: RCM


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e-mail: rcm@rcm.com.pl



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