Award of the Year 2007 for acuhorn rosso superiore175 loudspeakers in HIGH Fidelity Online

review in HIGH Fidelity Online floorstanding loudspeakers
acuhorn rosso superiore175 improved audio 2007
by Wojciech Pacula

Every once in a while HIGH Fidelity OnLine hosts products other than all the rest. Due to a specific construction, approach to a given issue, a brave idea, origin, and finally the making. Since the mainstream dictates the substantial majority of products presented by us, even though varied, they keep to the certain margin of freedom, a margin – let’s add – still and still redefined and redrawn. Sticking to the settled ways of thinking, allowing others to decide for us what and of what to think, rather shouldn’t be a priority to anyone who wishes to know more.

All I said above was triggered by one of the most controversial projects, namely loudspeakers with widerange drivers. In this case, the loudspeakers of acuhorn manufacture from Gdansk. The company is well known to us since we followed its doings from the very beginning, we tested their products and appreciated results. This was not, still, the type of sound I personally have preferred, however, several months spent first with one and next with the second design allowed to appreciate elements of sound that in multi-driver loudspeakers are very often lost or do not appear at all, such as coherence, absolute smoothness of transfers of transients and quick tonal changes, yet, to appreciate those advantages of widerange driver constructions one ought to spend some time with them.

The sound of the new constructions surprised even me, who was looking forward. This is a huge, huge step forward with respect to the previously tested models. Both with regard to the making of the product, which is now a true object of art, like Viennese Secession with its inclination to Cubist geometrical shapes, and with regard to sounding aspect from which a substantial amount of flaws was removed – the new loudspeakers constitute a remarkable achievement.

listening session

The new model is much much better. Generally speaking, in absolute categories this is a superb product. One of its features that immediately draws attention is an incredible soundstage. Even though one could expect some tricks with the stage, however, here we not only do not have any artifacts, zero showing off. The soundstage was exquisite in its definition, size and amazing uniformity, extremely rarely experienced by me. Omnidirectional loudspeakers (acuhorns are actually dipols, but they can be treated like omni- ones) generate usually very big, expansive stage, however only few can maintain simultaneously precise location without erasing the “foundation” under performers. Even when compared with the best constructions rosso are still an instance of exemplary realization of those assumptions. The soundstage had both clearly marked edges of instruments as well as their precise location with respect to each other. It was extensive – deep and wide, and still without losing focus on edges. I was really surprised with some sort of freedom in operating the space, in presenting all with a flourish, without squeezing all between loudspeakers. The loudspeakers, once we position them precisely – rosso will play very well even when positioned not so precisely, still, to achieve focus in the whole area they should be placed with an accuracy of 1 cm – they disappear completely, since the sound emanates from between, behind and sides of the loudspeakers.

I mentioned freedom of sound. It concerns not only pace but also dynamics. The dynamics is incredible. Even if in macro scale there are some limitations, but we will first burn the driver before we cause any stress to the loudspeakers. A basis for this is a very good microdynamics that unites all phases of emerging of sound and offers them freedom. So, even if in an absolute scale other loudspeakers will play more dynamically, still the absolute unity of the sound of rosso makes acuhorns play subjectively more “freely”, without restraints. When on the record of Barb Jungr „Walking in The Sun” (LINN Records, AKD 283, SACD/HDCD) enters bass, then it enters with a flourish, gracefully, showing very well a moment of hitting the string and fading its sound away. The sound is not thickened, rather, it is presented precisely. There is not a trace of warming or coloring of this band. Here we have plenty of information both about the performance technique and music.

First of all, one ought to say that there is really plenty of high frequencies. While playing a perfectly recorded „Dreamland” by Madeleine Peyroux (Atlantic/Warner Music, 82946, HDCD) one hears that in the high frequencies happens a lot, that nothing is sharp there or brightened. And still in absolute categories this range is slightly lowered, and edges, attack, are slightly veiled. I am not talking about rounding, this is not what I mean – the driver plays amazingly quick sound, without time for softening in a classic sense, through rounded attack and longer than usually passage into sustaining. Consequently, we have a cloud of sound plankton with a very pretty hue, a good location.

Still even not this makes acuhorn differ from classic speakers, but heard delicate upbeat of the passage of the central midrange and its upper part. I did not measure the loudspeakers but one can hear that it is at least several decibels. Thanks to such processing of this range the sound is always fresh and distinct, and not dull etc. when some of widerange speakers have that in excess. Also, one cannot view this range when cut off from other elements. Because along with a dynamic lower part frequencies – the loudspeakers go down really low – and handsome, delicate high frequencies (maybe their upper part is not too distinct, but it does not matter), it offers an open, swift sound with an excellent coherence. Still one needs to remember about this, e.g. when we listen to electronic music. And this type of music suits rosso superiore175 remarkably well. Since when on J.M. Jarre’s record „Téo&Téa” (AERO Productions/Warner Music, 699766, CD+DVD) we have sampled, extreme in midrange voice of Jarre (as I suppose), then it will usually sound quite forcibly, not that pleasant. And overall sound mentioned virtues invite to turn the volume really up. One may alleviate midrange energy with a warm tube, but then we would lose that clear bass and good high frequencies. And I do not advise this.

Regardless of a fact how unusual loudspeaker with a widerange driver did acuhorn achieved to make, still it is not the sound for everyman. Since there is no immediate pound of multi-driver speakers, and the upper part of frequencies is not that intense as from a good tweeter. And this decided midrange. Yet, the incredible soundstage, brilliant dynamics and coherence of sound establish a beautiful filling for the outstanding setting, namely the physicality of those loudspeakers. Still it is an extremely attractive alternative for other speakers. Those dear loudspeakers, once settled in a sophisticated interior, and connected to good electronic gear, they are sure to stay there forever.


acuhorn rosso superiore175 from Gdansk are very tall, horn dipol constructions with double widerage drivers acuhorn TSR200 – one emanates forwards, the other to the back, the horn outlet is also to the back. Finish is exquisite – the tested model was finished with ebony veneer. Plus we have brilliantly prepared metal elements of the drivers and bases. In the front they engraved the name of the company. At the bottom there is a wide thick plate that stabilizes a loudspeaker. To the plate featuring huge letters, an extremely attractively engraved name of the model, we screw in spikes. Single binding posts – this is a single driver dipol system – are superb, supposedly the most expensive, silver binding posts by German WBT Nextgen series – fixed to the vertical element of the base offering them a splendid foundation.

So much can be said basing on exterior examination of the loudspeakers. We asked the designers for a description: „The construction of the loudspeakers is made completely with full wood. We used 2,5-milimeter sheets, pressed together. Thick sheets cut across the tree-trunk maintain good firmness and transfer of sound. Alternative layout of wood offers next a strong, solid construction of an acoustic cabinet. Wooden instruments require a stable temperature and humidity to enjoy they sound for long. Our trademark are dipol loudspeakers. We applied the unique acoustic design using in one loudspeaker two drivers operating with four acoustic chambers with a common outlet. The height of a loudspeaker results from an application of two large bass chambers.

The driver is a genuine project of acuhorn manufacture. We developed a completely new design of construction of the chassis, a neodymium engine and of electro-mechanical elements of a driver. Its aluminium construction is cut with high precision by CNC machines. It allows to install coaxially a precise engine and moving elements of a driver. A light, only 4 g, membrane is made of pure paper and is fixed on a heavy foundation of a case. In an engine we use neodymium magnets with the highest produced thickness of a magnetic stream. The magnetic stream is passed through developed by us profile of driver’s engine that focuses the stream directly at the air gap, without dispersion and distortions. The engine of a driver reads information from a small quantity of rolls of a coil achieving the quality and clarity of reproduction of the best MC cartridges. Cabling used in the driver is reference silver (with golden molecules) Siltech G6 series.

The loudspeakers are equipped with black anodized bases offering the foundation for quick, precise transmission of sound. The loudspeakers may be leveled through screws placed in the bases, or fixed to the floor while using the holes next to the screws. In an aluminium base there are placed silver binding posts from the best series Nextgen WBT-0710 Ag. Connections are made with high quality pure WBT solder with 4% silver content. The cables are led in an air-teflon tunnel characterized by high surface resistivity.”

Altogether, the loudspeakers are made with an amazing precision and look really beautiful.

technical data:
drivers: acuhorn TSR200
impedance: 4 ohm
sensitivity: 99 dB
internal cabling: silver (with gold molecules) Siltech G6
binding posts: silver Nextgen WBT-0710 Ag
finish: ebony veneer
dimensions:20 x 40 x 175 cm
weight: 50 kg piece

Wojciech Pacula