improved audio 2007

Translation: Krzysztof Kalinkowski

From time to time on the pages of HFOL products are presented, that are different to those around them. Due to their special construction, approach of the problem, keen idea, their background or manufacture. I could have said that we host such products. The mainstream is just like most products we present, and although the presented devices differ among them, it is always within a margin of freedom, a margin – let us add that – that is being redefined over and over. Sticking to set ways of thinking, allowing others to decide about what our opinion should be and about what we should have an opinion, is by ways not a priority of anybody that wants to know more about something. And I hopefully have the right to assume, that people reading specialized press like HIGH Fidelity OnLine search for answers not only for the simplest questions like “What to attach to amplifier X with speakers Y?”. I have absolutely nothing about such questions, I know that for many this are real dilemmas, but I have a silent hope, that this is just the beginning of the adventure with the audio world. And the latter – and this I want to emphasize – is diverse.

There is only one truth. We can assume that, believe that, there exists an unquestionable absolute truth. Unfortunately, for me this is only possible in conjunction with faith. I am not thinking about belief in a supernatural being, but belief as an internal, not confirmed in 100% commitment to something. For me much closer is the Popper theory of falsifiability, the only method allowing to evolve. Because if something is not subject to discussion, is given only to belief (for Popper such an are is for example psychology), then it it is highly suspicious. And from here is not far to what we are dealing with, a way to find absolute sound. That, of course, does not exist. Reaching it is actually not the goal, but going there, valuable is that what is between the start and the finish.
It can be valued even more if we claim, that the absolute sound does not exist. I remind of that from time to time, but it is worth to discuss it sometimes. What is the absolute sound? The hardcore answer is as follows: “The absolute sound is the timbre of the instruments, human voice, environment emitted in natural conditions”. Let us leave aside electronic instruments as those can absolutely not be evaluated objectively (there is nothing like that in nature) and look at that what remained. Agreed – in ideal conditions the sound of a violin played live can be regarded as the absolute sound. But what violin? Each instruments sounds different. Each musician plays different sounds from the same instrument. Let's go on – in what surroundings? Outside, in a studio, in a given concert hall, with an audience or without it? Do you see it? Even if there is something as an exemplary sound of a violin, it is, from operational point of view, completely not applicable, because it will be the sound of THIS given instrument, played by THIS musician, in THIS room, and in THOSE environmental conditions. Every change of each one of those elements results in a change of the sound. If we would like to treat the natural sound as reference, then we would need to confront the recordings listened to on the tested equipment with the concert we witnessed. Even more – we would have to repeat the listening to the original before every testing session, otherwise we would have no certainty, that we remember well the sound of the original. It is easy to see, that the described procedure is so little possible in practice, that we can assume it is impossible.

But... I agree with all that I've written above, but there is something like a consensus. It means, that we agree that we know how the violin sounds, taking for this sound a median from so many listening sessions, in so many acoustical environments. We all know, or at least we think we do, how a given instrument sounds, even if we did not hear it for some time. The thing is that this is not an absolute master, but a standard that could be called “imagined”. Yes! But this means that there is a margin in the “accuracy” of reproducing music, a not fully defined space, that can be accepted by all participants of this discussion. Meaning us – music lover, audiophiles, music lovers/audiophiles and audiophiles/music lovers. Do you see where I am driving at? I am heading to that, that although we strive for the ideal sound, it does not exist. I am aiming also at the fact, that although there is a consensus of the “imagined” sound, then in the boundaries of the mentioned margin, it can be approached from many ways, preferring some values before others, valuing some aspects of the sound more than others.

Did I mention, that it is not really known, what sound we search for – that related to the fact of the recording, or that registered one? Because this are two completely different conceptions. We hear differently in a concert hall, the microphones “hear” differently, and even their best configuration is unable to reproduce the real thing. That is the reason so many recording techniques exist. But – let us leave that for later. It is important that my message reaches you: music can be reached in many ways. And although many times, sometimes in lengthy discussions with the Harpia Acoustics representatives, a company whose speakers I use on a daily basis, I heard that there is only one true sound, with all due respect – shown by using those speakers as a tool – I stick to my version...;

And all this has been provoked by one of the most controversial projects among the society of speaker constructors, namely wide range speakers. In this case made by the Gdańsk company Accuhorn. The company is not unknown to us, we watched it from the very beginning, tested their products and appreciated their achievements. This was not the kind of sound I did prefer, but a few months spent with one and later with the second construction, allowed to appreciate the elements of the sound lost often in multi-speaker designs, or even not existent in those, like coherence, absolute smoothness of the transients and quick tonal changes, also the uniformity of the sound. But to learn to appreciate the advantages of the wide range speakers it is necessary to spend some time with them – a month, two or three, listening also to classic constructions (although “classic” in terms of loudspeaker industry are the wide range speakers). Otherwise the lack of a strong treble, colorations inheritable related to such speakers will be dominant, and will not allow to go to next step. Many travelers that went to those regions never came back and every contact with loudspeakers equipped with many specialized drivers makes them exhibit depressive moods and allergy to their faults. And those are not that burdensome, at least when we listen to such modern speakers on a daily basis.

So when the sound of older models of Acuhorn could not be called accurate, then the sound of the new construction surprised even me, and I was prepared. This is a huge, really huge step forward with regard to the previously tested models. In the sphere of the product make, that is now a real piece of art, something in the style of Vienna Art Nouveau, with it's likeness of cubic, geometrical solids, as well as in the area of sound, where many shortcomings were removed, the new speakers are an unusual achievement. The price of the speakers had also dramatically risen. Both the materials used for the construction as well as the modifications to the speaker (this is now the Tesla TSR200 in Acuhorn version) are very costly. But a chunk of the price should be treated as price paid for an object of art, “object d'arte”, some added value.


First a short anecdote. I started the listening session after becoming acquainted with the manufacturers recommendations regarding their placement, accompanying electronics, etc. But when I sat down in front of the set-up Acuhorns from the very beginning it seemed to me, that there is no treble just like before it wasn't. It turned out that you need to tell the editors everything twice. To have them remember. Because the speakers were placed with the tubes facing forward, and I did not notice that there s something wrong here. I mean, it sounded OK, but on the bottom of my soul there was a question: “Where is the promised treble?” That what bothered me most in previous constructions of this company, the quickly falling-off treble range, returned also this time, with lower intensity, but clearly “marking” every recording with it's signature. And only after a while I was enlightened. Although I congratulated myself on the idea of setting the speakers up in parallel, exactly as written in the user's manual, but I placed them ... front to back. Yes, you can laugh, this is a good moment to mock upon “Mr Editor”. In my self-defense I can only say that the loudspeakers look the same from both sides, the only difference being the tube output on one of the baffles. Good, that I didn't place them sideways :-)

After turning around the speakers and putting them in the right way, it quickly turned out that these are completely different Acuhorns than those I got used to. The new model is many times better. In general, in absolute categories, this is a top notch product. One of the things that immediately catches attention is the incredible sound stage. It could be expected, that there would be some tricks with the stage, but here were no artifacts, no stunts. The stage was splendid in it's definition, size and an incredible, extremely rarely experienced by me, uniformity. Omnipolar speakers (the Acuhorns are actually dipoles, but they can be treated as omnipolars) generate usually a very large, expansive stage, but only a selection of them (like the Duevel Bella Luna) can keep focused localization, without effacing the “ground” below the performers. Even put against the best designs the Rosso are an example of exemplary realization of this assumptions. The stage had very clearly marked edges of the instruments, as well as precise localization among themselves. It was vast – deep and broad, but did not loose focus on the edges. I was really surprised with the ease of manipulating the space, showing everything with swing, without putting everything between the speakers. The latter, if we place them thoroughly – Rosso will sound nice if we place them far from neat, but if we want to have focus in the whole area, they have to be placed with 1cm precision – just disappear. With the exception of a few elements of the midrange (about that in a moment) everything seems to be played from a hidden monitor in front of us, because the sound is between and on the sides of the speakers.

I mentioned freedom. Not only with regard to space but also dynamics. This is just incredible. Although in the macro scale there are limits, but we will fry the driver easier than stress the speakers. The base for that is the microdynamics, that connects all phases of the creation of the sound and gives them freedom. So even if in the absolute scale the Dobermann of Harpia Acoustics will sound more dynamic, the absolute unity of the sound of Rosso makes them subjectively sound in a more “free”, boundary-less way. When on the disc of Barb Jungr – Walking in the Sun (LINN Records, AKD 283, SACD/HDCD) the bass is entered, then it enters with swing, grace, showing very well the moment the strings are hit and its reverb. The sound is not thickened, what could be feared when looking at the big tube outlet, but rather shown precisely. There is no trace of warming, or rather coloring of this frequency range known from the previous constructions based on the TS100 driver. Here we have many informations about the technique of playing as well as music itself.

Going up we come to the elements that will decide about love or hate – the speakers provoke extreme emotions. First of all there is need to say, that there is really a lot of the treble. Playing the perfectly recorded disc Dreamland of Madeleine Peyroux (Atlantic/Warner Music, 82946, HDCD) it can be heard, that there is much happening in the upper frequencies, that there is nothing sharp there, or even more brightened. But in absolute categories that range is slightly lowered, and the edges, the attack, are slightly veiled. I am not talking about rounding, because it is not about that here – the speaker plays with an incredibly quick sound, where there is no time for softening in the classic meaning, by the rounded attack and longer than usual passing into sustain. Between the speakers we have a cloud of musical plankton, with a very nice timbre, good localization but without that resonant attack like this from the SEAS dome used in the Dobermann.

But not even that distinguishes the Acuhorns from classic speakers, but the audible slight upping of the verge of central and upper midrange. I did not measure the speakers, but it can be heard as if it would be at least a few decibels. This is even natural – there is no chance of manufacturing a wide range driver with an ideally flat frequency response. This one here makes miracles, but it cannot surpass itself. Due to that way of reproduction this range is always fresh and clear, without a trace of slowdown, that is a sin of many similar designs. Because with a dynamic bass – the speakers go really low – and a nice, delicate treble (maybe there is not very much of it in the higher range, but...) it gives an open, quick sound with a splendid coherence. But we have to remember about the coloring, for example when listening to electronic music. And for that kind of music Rosso Superiore175 is just perfect. If we have, like on the disc of J.M. Jarre - Téo&Téa (AERO Productions/Warner Music, 699766, CD+DVD) we have a sampled, tuned on the midrange voice of Jarre (as I presume), then it will sound quite emphatically, and not very nice. And the mentioned assets allow for listening very loud. We can fight with this with the aid of a warm tube, but we would loose the clear bass and good treble. And this I will not recommend.

Regardless of that, how unusual speaker with a wide range driver Acuhorn did make, it is still not a sound that will attract many people. Rather not many. There is no immediate touchability of the speakers based on many drivers, the treble is not as strong as from a good dome. And that stronger midrange... But there is an incredible sound stage, ingenious dynamics and coherence of the sound that are a beautiful filling of the brilliant frame, made from the physical appearance of the speakers. In absolute terms it is not a sound leveled in terms of frequency, or having ultra-low distortion. But it is an appealing alternative to other speakers. And though the price is very high, the speakers once installed in a tasteful interior, connected to good electronics have a chance of staying there.


The speakers Rosso Superiore175 of the Gdańsk company Acuhorn are very high, tube constructions of the dipole type with two wide range drivers from Tesla – TRS200 – one radiating to the front and one to the back, where the outlet of the tube is placed. The finish is splendid – the tested version is finished in ebony wood. In addition we have brilliantly prepared – to date I was not aware that somebody in Poland can process and anodize aluminum in that way – metal elements: speaker frames and pedestal. The first are to strengthen the place the driver is mounted, as well as improve the looks. On the brim the name of the company is engraved. Much more elaborate and expensive in preparation is the pedestal: the lowest part is broad, thick plate, stabilizing the speaker. To the plate, where the name of the speaker model is engraved in big nice looking letters, we screw the spikes. The single terminals- this is a one way, two speaker setup – outstanding, probably most expensive, silver sockets from the German company WBT from the Nextgen series – are screwed vertically to this element of the pedestal, allowing them to have a very solid mounting.

That much can be said about the speakers from the outside. So we asked the makers for a description:
“ The construction of the speaker is made of full wood. We used 2.5mm slices, pressed together. Thick slices cut transversally from the wood stem keep good hardness and sound transfer. Alternating positioning of the wood gives a strong, solid construction of the acoustic chest. Wooden instruments require constant temperature and humidity, to be able to enjoy their sound for a long time. Our specialty are dipole speakers. We used one of kind acoustical project, using in one speaker two drivers working with four resonance chambers with a common outlet. The height of the speakers comes from using two large bass chambers.

The driver is an own project of the company Acuhorn. We designed a completely new project of the construction of the enclosure, neodymium drive and the electromechanical elements of the speaker. The aluminum construction is cut with great precision by digital machine tools. This allows for coaxial placement of the precise drive and moving elements of the speaker. The light, weighting only 4g, membrane made from pure paper is hung on the heavy enclosure. In the drive we use neodymium magnets with the highest available density of the magnetic flux. The flux is transmitted by a designed by us profile of the pole caps, that condense the flux directly at the slit without dispersion or distortion. The speaker drive reads the information from the low number of twists of the coil, achieving the quality and clarity of reproduction comparable with the best MC gramophone elements. The wiring used in the speaker are the silver (with addition of gold) Siltech cables from the reference series G6.

The speakers are equipped in black anodized aluminum bases, being the foundation of precise and quick reproduction of sound. The speakers can be leveled by the screws placed in the bases, or screwed to floor using the holes next to the screws. In the aluminum bases the silver sockets from the top series Nextgen WBT-0710 Ag are placed. The connections were made using WBT solder with 4% silver. The cables are wired in an air-Teflon tunnel, characterized by a high inherent impedance.”

Regardless of what, when and how, it is necessary to tell, that the speakers are manufactured with an incredible precision and look really beautiful.

TECHNICAL SPECIFICATIONS (according to manufacturer)
Speakers: Acuhorn (Tesla) TSR200
Effectiveness: 99dB
Internal wiring: silver (with addition of gold molecules) Siltech G6
Wiring terminals: silver Nextgen WBT-0710 Ag
Finish: ebony veneer
Dimensions: 20 x 40 x 175cm
Weight: 50kg piece

improved audio 2007

Price: 11 700 Euro

Distribution: Acuhorn

Tel. 601 622528

e-mail: info@acuhorn.pl



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