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Focal Trio6 Be

Active Three–way Monitors
Published October 2015
By Bob Thomas

Focal Trio6 Be

French speaker makers Focal continue their campaign of innovation, with this classy new three–way monitor design.

Focal have built up a stellar reputation in the domestic hi–fi and studio monitor markets over the last 30 years by producing some of the most highly–regarded active and passive loudspeakers to come to market. By keeping design, development and production of cabinets, transducers and amplification in–house, Focal have been able to optimise their products for their intended markets and end–users.

Focal’s latest nearfield studio monitor, the Trio6 Be, is a case in point. Their flagship SM9 (which I reviewed in the January 2013 edition) created the demand for a more affordable monitor that could be easily integrated into smaller studio spaces but that would also deliver the high SPLs required, in particular, by EDM artists, producers and engineers. Sitting mid-way, in terms of price, between the SM9 and the Twin6 Be, the Trio6 Be features new Focal mid–range and bass drivers, new Focal amplifiers and a cunning construction that allows operation in vertical and horizontal mirror–image orientations.

Open The Box

The workings of the Trio6 Be are contained in a substantial, stylish, textured grey and black rectangular enclosure made of 22mm MDF. The largest front–panel features are two 8.5–inch diameter openings, one of which is filled by the new eight–inch woofer, and the other by a rotatable circular aluminium baffle that carries the new five–inch mid–range/woofer, a pair of port vents and the one–inch, inverted–dome, pure beryllium tweeter from the SM9. A narrow, rectangular bass reflex port runs across the width of what is the bottom of the front panel when the Trio6 Be is used in its vertical orientation.

The cones of both the new five–inch and eight–inch drivers are constructed from Focal’s proprietary ‘W’ glass–fibre/foam/glass–fibre sandwich, to maximise damping, rigidity and mass.

The metal rear panel is completely devoid of heatsinks — we’ll come to the why of that later — but it does carry the balanced XLR input (switchable between –10 and +4 dBu) and the recessed slotted potentiometers that set the Trio6 Be’s two–band shelving EQ and its variable–depth 160Hz notch filter. Two TS jack sockets allow the connection and daisy-chaining of the standard latching footswitch (not supplied) that activates the Focus function: a mode in which the speaker switches to two–way operation, disabling the bass woofer.

With X–ray vision, you’d be able to see the three internal amplifiers — 100W Class–AB for the treble, 150W Class–G for the mid–range and 200W for the bass — and the ABS and glass–fibre cover on the rear of the circular baffle that protects the higher–frequency units from passive crosstalk between them and the woofer.

Setting Up

Installing the Trio6 Be is not exactly an onerous process — at least, not once you’ve wrestled the two 20kg enclosures onto a pair of sturdy stands and removed the transducers’ individual protective transit covers. The first decision is which orientation to mount them in. Personally, I think that I’d tend to go for the vertical position in small, narrow or acoustically suspect rooms but, because my listening room has a good acoustic and is fairly large, I went for the horizontal option. The Trio6 Be leaves the factory with the rotatable baffle in its vertical orientation; changing to the horizontal involves removing four Allen bolts (courtesy of the supplied key), grasping the two vents, pulling the baffle slightly forward and rotating it by 90 degrees.

If you’re going to be working at a distance of less than 1.5m away from the Trio6 Be in horizontal mode, Focal recommend that you set them up with the bass drivers on the inside and a tweeter–to–tweeter distance of 1.8 to 2 metres. At greater distances you can set up with the bass drivers on the outside, which is precisely what I did.

Since they’re front–ported, you can back the Trio6 Be up against a wall without any phase issues arising. The two shelving EQs deliver 3dB of boost or cut, so they’re really there to give you a gentle tailoring rather than anything else. The notch filter delivers ±3dB of adjustment at 160Hz, enabling you to compensate for any low–mid reflections from your console.

As I didn’t have any problems in the room, I left everything flat, ran the Trio6 Be pair in over a few days and, once I was happy that nothing was changing noticeably from day to day, I started listening in earnest.

In Use

Listening to the Trio6 Be in its three–way mode across a range of material reminded me very much of the SM9. The clarity, detail and balance throughout the frequency spectrum that had so impressed me on that stunning monitor were all there on the Trio6 Be, as was the effortless, smooth high–frequency reproduction (extending out to 40kHz) that, to me, characterises the sound of Focal’s inverted–dome beryllium tweeter.

I felt that I did detect a slight difference in that the Trio6 Be sounded to me slightly more forward and perhaps slightly punchier in the mid-range, giving it possibly a slightly tighter control of transient detail. In the lower frequencies, the Trio6 Be sounded solid, controlled and well extended. Lacking an auxiliary bass radiator, the Trio6 Be doesn’t get quite as low down as the SM9, but the 5Hz difference at the –3dB point between the SM9’s 30Hz and the Trio6 Be’s 35Hz is a pretty moot point anywhere other than a high–end control room. More important to me was that tracks by the likes of Deadmau5, CoH and others of that ilk could be cranked up to the point where I could physically feel the bottom end without the two Trio6 Bes sounding as though they were under any strain whatsoever — unlike my neighbours’ goodwill!

Returning to more reasonable volume levels with the highly detailed recording of baroque instruments and voices on L’Arpeggiata’s CD Via Crucis and, in particular, the track ‘Maria’, which features the Corsican male vocal quartet Barbara Furtuna accompanied by theobro lutes, baroque guitars, dulcimer, cornet and double bass, I was struck by the ease with which the Trio6 Be was able to resolve extremely fine transient detail across the entire frequency range.

This review coincided with the arrival of the September 2015 issue of SOS, containing an article on the recording of the Chris Thile, Stuart Duncan, Edgar Meyer and Yo–Yo Ma CD The Goat Rodeo Sessions. Since I own the CD, I spent an enjoyable (and instructive) time going through the tracks on the Trio6 Be, listening out for examples of the various techniques employed and the points made by Richard King in the article.

Another key listen was a track from the CD Spes by the choir Cantus on the Swedish 2L label. The actual setup and recording of the track — Frode Fjellheim’s ‘Njoktje (The Swan)’, featuring the composer on lead vocal and synthesiser — can be seen on an HD YouTube video, and listening to the track alongside the video was again interesting and instructive, the Trio6 Be bringing out some very fine, low–level detail in the recording.

Superb though the performance of the Trio6 Be was, perhaps the most impressive part was that, throughout the review, the back panels never felt unduly warm, despite the complete absence of the usual essential external heatsink. This review was the first time that I have knowingly encountered Class–G audio amplifiers. As you’ll see in the explanatory box, the basic premise of this class of amplifiers is that an increase in the level of an input signal is accompanied by an instantaneous increase in the effective rail voltage sufficient to amplify that signal. In the Trio6 Be, the rail voltage is supplied by a pulse–width-modulated power supply. This type of power supply — often found in in–car amplifiers — is able to maintain a constant rail voltage across a wide range of loads, unlike a conventional supply that can sag (and thus limit the amplifier output) under a heavy load, such as a large transient. Electric guitarists are familiar with this effect in valve amplifiers, where it is often considered desirable, with the opposite being true in a studio monitor. I do wonder if this combination of Class–G amplification and solid multiple rail voltages from the PWM power supply in the Trio6 Be might partially account for the high level of transient detail.

Having explored the 35Hz to 40kHz (–3dB) three–way performance of the Trio6 Be, it was time to switch to its two–way Focus mode using (in my case) an elderly footswitch, at which point the bass driver is turned off and the tweeter and five–inch transducer are electronically revoiced to deliver a –3dB bandwidth of 90Hz to 20kHz. In this mode, the Trio6 Be enables you to check how your mix will transfer to lower–quality ‘bass–challenged’ systems, and will throw up any issues in the high bass and mid-range that need addressing for those types of systems. For me, this is an invaluable facility as it also enables you to focus in on any mid–range and high–frequency issues. The addition of the footswitch remote control means that you can switch to Focus mode without moving from your listening position, which is an impossibility on the SM9.


By any measure, the Focal Trio6 Be is a monitor of extremely high quality. In three–way mode it delivers a level of transient detail, frequency balance and clarity that is of the highest order. In the two–way Focus mode it turns into a tool for detailed analysis of the mid-range and higher frequencies, and for checking how a mix transfers to lower–quality systems.

Designed to answer the demand for a more affordable SM9 that is able to deliver the performance required by EDM and similar genres, and that is more easily integrated into less than perfect audio environments, I think the Trio6 Be has succeeded on all counts without sacrificing the accuracy, balance and superb sound quality that characterise all of Focal’s monitors.

Of course, ‘more affordable’ is a relative term, but the price of the Trio6 Be is more than reasonable given the superb performance of which it is capable. If you’re in the fortunate position of being able to purchase a monitor at this price then you simply must audition it.


At this level of performance — in addition to Focal’s own SM9 — you’ll no doubt be assessing alternatives from all the major manufacturers. The likes of Adam, ATC, Dynaudio, Eve, Genelec, Neumann and PMC all have products that are as capable of unlocking your wallet.

Class-G Amplification

Although we love their sound quality, Class–AB amplifiers are inherently inefficient, dissipating some 40 to 50 percent of their power as heat. We’d all like Class AB to be more efficient, as that would enable amplifiers to be made smaller and lighter, and would obviate the need for the relatively massive heatsinks that are essential to their design. In pursuit of these goals (and lower costs) many manufacturers nowadays are abandoning Class AB and switching instead to Class-D PWM amplification, which offers efficiencies in the order of 90 percent.

Class G, in essence, is a more efficient version of Class AB. The output power of any amplifier depends on the voltage in its power rail — the higher the rail voltage, the more power the amplifier can output before clipping. However, musical signals are, by nature, highly dynamic and the signal transients and peaks that would drive an amplifier towards its maximum output tend to be of extremely short duration. This means that, for most of the time, the amplifier’s available power is not being fully used, and that which is not used is dissipated as heat.

Class–G amplifiers are designed to minimise this inefficient power dissipation by employing multiple pairs of power rails in increasing voltage steps. One pair of rails supplies a low voltage that is used to amplify low–level signals. As the signal level increases and these rails approach their clipping point, the amplifier switches in the next higher pair of voltage rails, and so on. The rails in the chain are switched on sequentially (and instantaneously) as and when required, thereby increasing the power of the amplifier only for the time necessary to amplify the signal being fed to the amplifier’s output stage.

This concept is somewhat analogous to the variable displacement technology used in some high–performance, multi–cylinder car engines, in which the outer pair (or pairs) of cylinders are deactivated by the engine management system when their power is not required, in order to improve fuel economy. They are reactivated instantly when the driver puts his or her foot down.

Published October 2015