Author: NickolayYefremov 
October, 2020

It is not that complicated to design a large-sized acoustic system for big spaces. This niche has been captured by Public Address companies. Whereas there is only a handful of audiophile systems the sound of which can impress you in a larger listening room. It is not easy to mix the sound correctly, to synchronize a large number of tweeters and to shape the bass in order to avoid distortions if the speakers are positioned too close to the walls.

Grandeluna loudspeaker system is quite massive in size. Each loudspeaker weighs a quarter of a ton and its height is over 2 meters. The manufacturer had to work hard in order to achieve a fused and detailed sound. Let me remind you that the company was founded by Viktor Porkalov in Verona and he also acts as an engineer, designer, cabinetmaker and sales manager. There is no mass production –  it is almost 90% manual work. Even the tweeters are manufactured by Viktor – starting from calculating the magnetic circuit finishing with the product itself. The baskets and magnets are bought separately; the coils are wind in a small workshop. When asked which crossovers he prefers Viktor replied: “I prefer not to talk about it since my filters are different from all the others. Each time I choose the scheme experimentally. The main thing is that there is a result and you can hear it.” The scheme is designed for each tweeter individually and it is constantly being improved during adjustments. The boards of the filters are cast with compound for stability of the parameters so that they can be covered by a lifetime warranty.


Viktor distrusts phase inverters and believes that the bass should be fast. That is why all SonusVictor systems including Gradeluna have sealed enclosure.


Since the product is custom made, there is no reason to have your own production assembly facility with workers. Viktor designs the boxes himself and sends the blueprints to an elite furniture factory in Vicenza. Viktor monitors the manufacturing process of the first pair and then the process is run automatically.


SonusVictor Grandeluna has nine dynamic tweeters two of which are installed in the back wall of the box. They are a 26-mm tweeter and a 2-inch mid-range speaker both with silk domes. The loss of the high-pitched part due to the sound absorption in the room with acoustic treatment is compensated by the rear sound radiation. Furthermore, this pair of uniform domes gives a peculiar spatial effect (which I will describe a little bit later).

Seven dynamic tweeters are installed in the front wall of the loudspeaker. The box of Gradeluna is multi-layered, glued from several High Density Fibreboards which are much denser than regular MDF. The overall wall thickness is 50 mm. Our version is covered with ebony wood veneer, finished with gloss varnish and mirror polished. The acoustic system can be custom-ordered in other fine wood veneer or RAL code finish.



We intentionally did not choose Ultra High Endcomponents for the test system. We followed the principle of reasonable sufficiency. Linn Ikemi CD-player was connected to a tri-block Praecisa Acustica A3 Gold amplifier consisting of a preamplifier and an amplifier with external power supply and 2 х 200 Watt amplifier with MOSFETах field transistors. When listening to Mezzaluna the first thing that I noticed was the transmission of the onset whereas with Grandeluna the highlight is the soundstage. The specific positioning of the speakers on the front wall and two tweeters on the rear wall resulted in unusual and interesting effects. Part of the virtual images from the background scene moved to the front line, while listening to some records it seemed that the drums set was positioned within two meters from it. And that gave rise to a seeming paradox with the wall of the room – in reality the wall was in front of me but the spatial impression from the sound suggested that the wall did not exist.

Since Gradeluna tweeters are positioned exactly at ear level they give acute localisation of high pitch details which in combination with the removed background results in a genuine 3D diorama effect in almost all of the records.

I started with that because this degree of detail came as a pleasant surprise bearing in mind the dimensions of the system and when used in a relatively small room. This range of dynamic was entirely expected when four 12-inch drivers work together. However, certain features appeared – first of all the speed of the onset and reverberations that are naturally fading after the beat until reaching the noise floor. By these standards, it is not easy to outmatch paper tweeters in a sealed box. The performance is light and open but the large drum and full orchestral tutti actually hit you in the chest.

The bass is really low however for the reasons stated above it does not seem heavy. At first, it seems weird – you do not have your usual 17 Hzbut then you realize that the sound is not rubbery and without stretched notes, and the room does not play along with resonant modes. And this lightness of the low bass buys you over – all the sounds in this range are clearly distinguished and you can define their origin according to the tone colour and the character of the onset. Finally we get to the sound fusion. It is a whole other level of pleasure to sit in the close vicinity of a two meters high acoustic system with seven working speakers and to feel almost tangible sound images. The soundstage spreads higher that gives it a sense of additional scale. And the horizontal diagram is broad to such an extent that even three or four people can listen to the music on equal terms. Gradeluna loudspeaker system will sound great at crowded family gatherings since you can listen to it while standing far away. Even in this case you will not need a powerful amplification. With this level of sensitivity 100 watts for one channel is enough to cover 100 sq. m. venue.

Butfirst of all Gradeluna is an audiophile project for sophisticated listeners. And this system can prove its purpose in almost all settings and with any music genre.




Manufacturer: Sonus Victor (Italy)




Dali, «In Admiration of Music. Volume 4». Dali CD, 2015

Dream Theater, «Falling Into Infinity». EastWest Records, 1997

Sweetbox. BMG/RCA, 1998

Jean Sibelius «Violin Concerto». Anne-Sophie Mutter & Staatskapelle Dresden. Deutsche Grammophon, 1995

Ella Fitzgerald & Louis Armstrong, «Porgy & Bess». Verve, 1958



Linn Ikemi CD-player

Praecisa Acustica A/3 Gold preamplifier

Praecisa Acustica NS A/3 Gold amplifier


Interconnecting: Accuphase Super Refined Cable ASLC-10

Acoustic: Musical Wire Cadence Signature Speaker Banana 2.5m


System type: 9-driver, 4+3 way|| Acoustical load: sealed box || Frequency response: 17 — 30 000 Hz || Sensitivity: 92 dB (2,83 V/1 m) || Nominal impedance: 4 Ohms || Band splitting frequencies: n/a || Recommended Power: 2 х (60 – 600 Watts)|| Enclosure: fine wood veneer, custom RAL code on special order || Dimensions: 2020 x 450 x 620 mm || Price per pair: €240.00


System type

Standmount loudspeaker system, sealed box, 4+3 way

Frequency response: 17Hz-30kHz

Sensitivity: 92dB

Recommended Power: 600Watts

Impedance: 4 Ohms


Loudspeakers front

1 Super Tw Ø 26 mm silk dome

1 Tw Ø 26 mm silk dome

2 Md Ø 200 mm treated paper

1 Wf Ø 250 mm treated paper

2 Wf Ø 320 mm treated paper


Loudspeakers back

1 Tw Ø 26 mm silk dome

1 Md Ø 50 mm silk dome



MUNDORF components silenced in pairs, hand-assembled crossover, speakers Sonus Victor, Sonus Victor connectors



H2020x W460 x D620 mm



Cabinet: layered HDF (High Density Fibreboard)

Finishing: fine wood veneer or painting in any color

Grille: Black acoustic fabric