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Focal ST6 Solo6 & Sub12

Active Monitors + Sub By Bob Thomas
Published September 2023

Focal ST6 Solo6 & Sub12

Focal’s new active nearfield speakers represent a significant update on their predecessors, and the matching subwoofer is a powerful beast!

French speaker manufacturers Focal first came to prominence in the hi‑fi market, where they remain a major player. Since 1982, they have also been building a stellar reputation in the studio monitor market. Their newest range is the ST6 series, which comprises the Twin6 (reviewed in SOS October 2022) and the subjects of this review, the Solo6 and Sub12.

The ST6 Twin6 and ST6 Solo6 take over from the (non‑ST) Twin6 Be and Solo6 Be in Focal’s portfolio, whilst the Sub12, with its 13‑inch driver, assumes the title of Focal’s largest ever (and heaviest) active subwoofer from the SM6 series’ 11‑inch Sub6.

At first glance, you’d be forgiven for thinking that little has changed since between the Solo6 Be and the new ST6 version. Although I noticed that the ash‑veneered side panels are now stained a slightly more vibrant shade of red, I completely missed the fact that the Solo6 is approximately 0.5cm larger all round and 2kg heavier, thanks to its thicker (22mm) panels and revised internal braces. Other obvious changes are the bevelled side panels and the front baffle’s rounded top and bottom edges, aimed at reducing cabinet diffraction. The ST6 Solo6 features a taller version of its predecessor’s reflex port. This features internal and external flaring designed to create a laminar air flow, which helps minimise distortion, enhance the bass response, and reduce port noise.

The Focal logo has moved from the front baffle to the top of the cabinet. And, in a major departure from the Solo6 Be, Focal’s signature beryllium inverted‑dome tweeter now sits inside an acoustically optimised baffle and directivity guide.


The baffle itself appears to me to be an evolution of those found on Focal’s Shape and Alpha Evo speakers. The tweeter sits in the centre of an obround (racetrack‑shaped) recessed area, whose angled boundary walls create a somewhat ‘dog‑bone’ shaped outline. The walls in the centre of the obround above and below the tweeter have a steeper angle than those on the curved ends, with the aim of minimising both the tweeter’s interaction with the bass/mid driver, and diffraction effects arising at the top edge of the cabinet. The shallower angle of the curved end sections is said to deliver wider dispersion (and so a larger sweet spot) compared to the older Solo6 Be.

Another visually obvious change is the large grille that protects the beryllium tweeter. The grille contours are shaped in order to minimise any potential influence on the tweeter’s high‑frequency dispersion characteristics. Though not the first Focal studio monitors to be given a tweeter grille, the ST6 series speakers are the first to have been fitted with this contoured version.

The ST6 Solo6 is an all‑analogue speaker, so there are no digital inputs, and all response adjustment takes place in the analogue domain.The ST6 Solo6 is an all‑analogue speaker, so there are no digital inputs, and all response adjustment takes place in the analogue domain.The beryllium tweeter in the Solo6, like that of the Twin6, incorporates Focal’s proprietary Infinite Acoustic Load (IAL) housing, in which the tweeter is mounted in its own enclosure, which very gently absorbs the sound from the rear of the tweeter diaphragm. The benefit of this approach is that it improves articulation and greatly reduces distortion in the 1‑4 kHz range, resulting in a more natural overall sound.

W Is For Woofer

The ST6 series’ 6.5‑inch bass/mid driver is a new design incorporating another proprietary Focal technology, the ‘W’ composite cone. Made up of a structural foam core sandwiched between two sheets of woven glass tissue, this cone’s combination of lightness and rigidity, together with the precise control of the cone’s damping characteristic afforded by varying the thickness of the foam core, is said by Focal to deliver very low distortion and an excellent phase response.

The cone has a deeper profile than that of its predecessor, which makes it more rigid and also means it can be made 1mm thinner. The voice coil is deeper (20mm) and more powerful, yielding 40 percent greater excursion, and the central dust cap is made from a lighter cardboard than before. All these enhancements not only make the new driver more responsive than the Solo6 Be, but also allow it to deliver a wider dynamic range and frequency response. And, of course, the driver also incorporates Focal’s patented Tuned Mass Damper surround, described in detail in our review of the Twin6.

BASH Street Kids

The Solo6 uses the same amplifier topologies as the Solo6 Be: a BASH (Bridged Amplifier Switching Hybrid) amp powering its bass/mid driver and a Class‑A/B amp driving the tweeter. The new speaker’s amplifiers are rated at approximately half the power of the Solo6 Be’s (80W RMS BASH and 50W RMS Class‑A/B), although at 110dB, their maximum SPL is only 3dB lower.

Unlike some competitors, Focal remain entirely analogue in their approach, so you will find no digital inputs, D‑A converters or onboard DSP on the Solo6. Instead, a ‑10dBu/+4dBV input level select switch feeds a simple EQ setup. This offers ±3dB shelving LF and HF EQ controls, at 250Hz and 4.5kHz respectively, to help compensate for room anomalies, and a 160Hz midrange peaking band to help deal with console reflections. A switched high‑pass filter acting at 45/60/90 Hz (or off) allows you to set the optimum crossover point when using a sub without its own crossover. Last but not least, Focal’s unique footswitchable Focus mode disengages the crossover and tweeter and sets the bass/mid driver’s frequency range to 100Hz‑10kHz, allowing you to check a mix through Focal’s approximation of a full‑range, single‑driver loudspeaker. Switching requires either a normal latching or momentary guitar pedal‑style footswitch, and can be chained between multiple ST6‑series loudspeakers in an installation. An LED mounted in the tweeter baffle next to the power LED illuminates when Focus mode is active.

At 62kg and measuring 60 x 48.7 x 56.8cm, the Sub12 is something of a beast!At 62kg and measuring 60 x 48.7 x 56.8cm, the Sub12 is something of a beast!

The Lowdown

Compared to the Solo6, the Sub12 is an absolute monster, both in size and weight. Its cabinet, which contains a 13‑inch driver, amplification and controls, weighs in at a total of 62kg and encloses a volume almost seven times that of a single Solo6. The cone of the Sub12’s driver is again of a W composite composition, delivering a frequency response of 28‑400 Hz at a maximum of 124.5dB SPL, thanks to its 600W RMS BASH amplifier. On the rear panel, input sensitivity can be switched between ‑10dBV and +4dBu, and signal polarity can be inverted, if necessary, prior to the fully variable 0‑180‑degree phase control. Continuous 50‑150 Hz low‑pass filter and ‑24dB to 0dB level controls are followed by a switched 45/60/90 Hz (or off) high‑pass filter. The LFE (Low Frequency Effects) and left/right audio inputs, like on the Solo6, are all analogue affairs, as are their associated outputs. The left and right outputs are high‑pass filtered at the frequency set on the Sub12’s filter.

The Sub12’s integration options include high‑ and low‑pass filtering, phase adjustment and switchable polarity.The Sub12’s integration options include high‑ and low‑pass filtering, phase adjustment and switchable polarity.

Alongside the two quarter‑inch TS I/O jack sockets for the Focus mode switching sits a second pair that allow footswitching and chaining of the Sub12’s 2.1 bypass function. This mutes the Sub12 and defeats its high‑pass filter, feeding full‑range signals to the left and right loudspeakers, allowing quick and easy comparisons between the 2.1 system (with sub) and a normal stereo setup (without sub).

Setting Up

Unless you have plenty of space behind your mixing console or studio furniture stand, setting up a Solo6/Sub12 2.1 monitor system in a conventional fashion does pose the question of where to put the Sub12, since it takes up a significant amount of floor space. After a fair amount of experimentation in my listening room, I settled on positioning the Sub12 so that its driver was centred between, and in the same vertical and horizontal planes as, the Solo6’s bass/mid drivers.

Balancing the 2.1 system wasn’t particularly difficult. After Focal’s recommended 20‑hour run‑in period and some careful listening, I settled on high‑passing the Solo6s at the Sub12’s 60Hz switch position, and low‑passing the Sub12 by ear at approximately the same point. I also attenuated the Sub12 by approximately 10dB. Having done all that, I engaged the 2.1 bypass mode on the sub and started listening to the Solo6 speakers in their full‑range mode.

In Use

When I first listened to the Solo6 they seemed very slightly more forward‑sounding than I’d expected. However, once the system was set up and I started listening critically, I came to realise that it was the level of transient detail and clarity overall that gave me that initial impression.

The detail was especially noticeable in one of my go‑to audition Hybrid SACD discs, the album Spes by the Norwegian all‑women choir Cantus (whose singing you may know from Frozen and Frozen II), with Frode Fjellheim (voice and synthesizers) and Snorre Bjerck (percussion). Originally recorded in DXD 352.8kHz/24‑bit format, in a Norwegian church with superb acoustics, Spes is a CD with many subtleties that demand much of a loudspeaker, but which also afford opportunities for a great speaker to shine. The Solo6 gave a superb account of itself in stereo playback. The sound stage was wide and deep, the centre image rock‑solid, vocals from the choir and the synthesizers and percussion were rendered impeccably, and natural reverberations fading into the dark silence of the cathedral ceiling — the sternest test of all — retained a high level of detail.

I heard the same level of solidity, width, depth and detail in another favourite, Via Crucis by Christina Pluhar and L’Arpeggiatia, an album of early Baroque and traditional Italian and Corsican music. This is another recording that makes enormous demands of a loudspeaker’s ability to resolve detail, and the Solo6 responded in exemplary fashion.

Having gone through stacks of my favourite CDs, and a few of my own recordings, I came to the conclusion that the Focal Solo6 has that rare ability to be both highly accurate and unforgiving when I was in ‘critical listening’ mode, and enjoyable to listen to when all that I wanted to hear was the music.

To my ears, the combination of the Solo6’s beryllium IAL tweeter and its Class‑A/B amplification delivers a smooth and extremely detailed performance that has a natural quality and isn’t a tiring listen. The new bass/mid driver and BASH amplification form another very impressive combination, whose increased excursion and control — coupled with the reductions in low‑end and midrange distortion delivered by Focal’s patented TMD surround — delivered a powerful, articulate bass and an impressively well defined and dynamic monitoring performance overall.

The integration between the Solo6’s tweeter and its bass/mid driver is exemplary and results in a wide, deep and detailed sound stage with a solid centre image and precisely positioned instruments and voices. If you’re working in genres that depend on extreme low‑frequency detail you’ll need to add a Sub12, but if you’re not, the Solo6’s low‑frequency performance is more than capable of providing enough information in the bass to enable you to make good mix decisions.

However, all gods have feet of clay and, for me, the clay in the Solo6 lies in its Focus mode, which didn’t really work for me. I really liked the Focus mode in the SM9 and Trio11 Be when I reviewed those, as their switch from three‑way to two‑way operation delivered practical benefits and added to their useability. My personal opinion is that a Focus mode with a frequency response curve similar to that of an Auratone or a Yamaha NS‑10M would have been more useful — but your mileage may vary.

The Sub12 produced the fastest, most detailed and most coherent low end that I have heard to date.


To put the Sub12 through its paces I used Deadmau5’s Grammy‑winning CD 4x4=12. This EDM classic is a particularly tough test of a loudspeaker’s ability to resolve and reproduce detail in the sub‑bass region. Simply put, the Sub12 produced the fastest, most detailed and most coherent low end that I have heard to date. My poor neighbours must have thought that a rave had started up in their back yard.

But the Sub12 isn’t only about EDM synth basses shaking the local foundations to the core. It’s also about reproducing low frequencies as part of 2.1, surround and Atmos systems. In the 2.1 review setup, the Sub12 produced exceptional results, integrating perfectly with the Solo6 pair and seamlessly extending their low‑frequency response.


With its relatively compact dimensions and rear‑panel mounting points, the Focal Solo6 is capable of fitting into any recording or playback environment, be it as a pair of shelf, console or wall‑mounted nearfield monitors in a professional or project studio or a mobile truck, or as part of a multi‑speaker system. Combining a pair of Solo6s with its partner Sub12 results in a 2.1 nearfield studio monitor system of the highest quality, the only constraint on which is the space required for the Sub12.

On their own, a pair of Solo6s are a superb nearfield monitoring solution at an attractive price given their performance level. Add in a Sub12 and you’ve got a 2.1 nearfield monitoring system that is capable of resolving the finer details in the extreme low frequencies from both acoustic and electronic instrumentation and percussion. If you have the need, budget and space for a system with the capabilities and performance of Focal’s ST6 series Solo6 and Sub12 combination then I urge you to audition them. You won’t be disappointed.  


If you’re looking for a pair of nearfields, consider the likes of ADAM Audio, Dynaudio, Eve Audio, Genelec, IK Multimedia and Neumann. There are fewer competing options for the Sub12, but if space is an issue, Genelec, HEDD Audio and Neumann offer more compact alternatives.


  • Focal’s signature beryllium tweeter is smooth and highly detailed.
  • Responsive, wide‑bandwidth, low‑distortion bass/mid driver on ST6.
  • Superb integration between tweeter and bass/low‑mid driver.
  • Sub12 is fast and detailed, and capable of both shaking foundations and delicately delineating the extreme low end.
  • Seamless integration between Sub12 and Solo6.


  • Solo6’s Focus mode doesn’t float my boat (though it might float yours).
  • Sub12 is large and heavy.


Separately, the Solo6 and Sub12 are superb studio monitors that deliver performances of the highest quality. Together, they are amazing.


Solo6 ST6 £2500 per pair. Sub12 £2250 per speaker. Prices include VAT.

SCV Distribution +44 (0)3301 222 500.

Solo6 ST6 $3198 per pair. Sub12 $2599 per speaker.

Focal Naim America +1 866 271 5689.

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