Founded in 1988, Solen is a company based in Grenoble that has long specialised in amplifiers, notably the Tigre hybrid integrated amplifiers, which are sold more widely abroad under the Ensemble brand than in France under their original name. Entering a new era a decade ago, the Alpine manufacturer recently began manufacturing loudspeakers, with two models already available in its catalogue, both based on HEL bass diffusion technology. Rather than the smaller metal HELya, we chose to start by exploring the more imposing the Solen HELios, a large 48 cm tall bookshelf speaker, whose Scan-Speak drivers are complemented by attractive cherry wood side panels and a dual-filter system.
Still relatively unknown on the British market, Grenoble-based brand Solen is celebrating its 35th anniversary this year. Long associated with its amplifiers, the company reinvented itself in 2015 to enter the digital converter market with its MuDac-300, directly derived from FPGA technologies developed for aeronautics by another branch of the group, before more recently launching into speaker design.
Now numbering two, these compact models stand out above all for a patent developed by Frédéric Gautier and tested by his close collaborator Daniel Galazzo, called HEL for “Hybrid Enclosed Line”. Available with the HELya in its metal case, which we will present later this year, this system, designed in 2019 to reproduce the sound of a horn loudspeaker while remaining more discreet, was improved during lockdown, giving rise in 2022 to the HELios, which we are testing for you today.
Based on a horizontal tube behind the 16.5 cm (6.5″) Scan-Speak mid-bass driver, HEL technology offers a very short wave dotted with acoustic traps, defined by cells that diffuse resonances around the core and limit residual resonances above 450 Hz, with waves virtually disappearing in the cabinet from 150 Hz onwards thanks to the line tuning slot located just behind the speaker.
Compared to prototypes built on classic bass-reflex models, designed to carry bass frequencies to the outlet vent, HEL technology has identified much better bass performance down to 35Hz, with no interference or cabinet effects and refined transient clarity. After numerous measurements, the engineers unanimously approved the process for integration into the HELios.
Above the mid-bass driver located in the centre of the enclosure, a tweeter, also from the Danish company Scan-Speak, handles the high frequencies with a crossover point set at 2.5kHz. The two-way speakers are connected to filters on printed circuit boards linked by copper cables, which use SCR polypropylene capacitors and correctors to eliminate bass and Helmholtz resonances, resulting in the flattest possible curve.
They are integrated into an MDF cabinet, reinforced on each side by two beautiful Alpine cherry wood panels. At the rear of the speaker, in addition to the terminals placed at the bottom on a diagonal break in the cabinet, the final part of the HEL technology can be seen, where the main core is blocked to allow air to escape through the secondary ports all around.
INSTALLING THE SOLEN HELIOS
Relatively large for compact speakers, the HELios are big bookshelf speakers whose dimensions are reminiscent of the AT13 from Atlantis Lab. They should therefore be placed at a relatively low height, ideally on 50 cm high stands such as the Solidsteel SS-5, where we used our SS-7s, alternating with lower Linn stands with a wider base, which are better suited although slightly less effective against vibrations.
With a sensitivity of 91.5 dB, these Solen speakers are easy to drive and posed no problem when paired with our small Luxman SQ-N150, which is only 2 x 10 W, in addition to matching the material it provided. We also connected them to more powerful amplifiers, without them saturating or showing any major limitations in the reproduction of bass or treble, even at high volumes.
THE SOUND OF THE SOLEN HELIOS
With a very open sound, the HELios give the impression of immediately releasing the air created by the sound waves. With no cabinet noise, Solen’s large bookshelf speakers allow the music to express itself instantly by sending the sound straight ahead, without trying to create too much width or height on the soundstage, but without sounding like monitor speakers either.
Spaced about three metres apart, they deliver great depth in addition to a very balanced sound, with no register out of place and no cut-off effect when switching between the tweeter and the mid-bass driver.
On Anne-Sophie Mutter’s Stradivarius during her “Devil’s Dance” with John Williams, the timbres come through beautifully thanks to the Scan-Speak membranes, right up to the highest trebles, without the sound of the violin ever becoming aggressive, even when it is deliberately sour.
The bass is also very open, giving the impression of being very airy, a result of the HEL technology, which is particularly beneficial for natural sounds, especially those of orchestras and real instruments. For the low registers of French rappers or – often better worked – American R&B singers, the clarity and airiness are slightly less suited, but without saturating before going very low in frequency.
With this type of music, as with our listening sessions of opera and soul, the voices are placed at the front of the soundstage, leaving a wide rear stage that gives the impression of great freedom of sound waves, with the same sense of airiness and speed in the responses, in addition to very beautiful clarity in the transients.
With this characteristic sound, the bass, which is less tense than on other models, blends with the midrange without ever putting the speaker dedicated to this part of the spectrum under strain, perfectly combined with the treble without any break-up or resonance effects when the frequency exceeds 2.5kHz.
OUR CONCLUSION
With an innovative design for bass management and a desire to reproduce timbres as accurately as possible by opening up the soundstage, Solen is entering the loudspeaker market to become a complete audiophile manufacturer. When paired with the brand’s amplifiers or mid-range models, the HELios speakers offer a very free sound with a wealth of detail, particularly noticeable in the depth of the image, thanks to the quality of their drivers and the management of internal and external waves.
Their character makes them particularly suited to natural music, even promoting the large masses of the greatest requiems and densest symphonies, with very good definition of complex instruments such as the organ, which can still be enjoyed to the full even when covered by the choir in a work such as Mahler’s Symphony No. 8 (Dudamel version, DG).
Author: Vincent Guillemin
TECHNICAL SHEET: SOLEN HELIOS
- Origin: France
- Price: €4,380
- Dimensions: 480 x 240 x 310 mm
- Weight: 12.5 kg
- Frequency response: 35 Hz-20 kHz
- Impedance: 4 ohms
- Sensitivity: 91.5 dB; 2.83 V/1 m
- Power handling: 55 W
