HECO

Celan Revolution 9 Floorstanding Loudspeaker

£4,099 RRP

Back in the days when valve amplifiers glowed away in most audiophiles' living rooms, low output power was the norm. Luckily, there were many high-efficiency loudspeakers around – often using tricks like horn loading – which made decent volume levels possible despite this. Then transistors arrived, and amplifiers got more powerful as a result. At the same time, speakers became more complex thanks to multiple driver arrays and high-order crossover networks, as designers chased ever more sophistication. Light paper cones became less common as heavier plastic types were developed; efficiency wasn't so much of an issue, as modern amplifiers had all the oomph they needed to drive them.

These days, valve amp fans face precisely the same problem – most speakers are too inefficient to get the best from them. As a convert to the breed, I know this all too well. But some super-sensitive speakers are still made by the likes of Klipsch, JBL, Audio Note and Lowther. I remember coming across a name I was not familiar with a few years back, recommended enthusiastically for use with low-wattage valve amps. That name is Heco, from Germany, and the speaker I first heard was the Direkt model.

Heco was founded more than seventy years ago, in 1949 and lays claim to having built the first production line for loudspeaker chassis a year later. It cemented its reputation with the successful six-litre Type B130, and marked its fortieth anniversary with the launch of the flagship Concerto Grosso. In 1990, it added compact subwoofers and satellite systems to its line-up. The original Celan range debuted in 2005, and at the 2015 High End Show in Munich, Heco unveiled the Direkt.

UP CLOSE

When I saw the new Celan Revolution range on the Henley Audio stand at the recent Bristol Hi-Fi show, I staked my claim straight away for a pair of the top-of-the-range Revolution 9. It immediately struck me as a lot of speaker for the money, with the efficiency needed for pairing with a good valve amp. The range starts with the bookshelf 2-way Revolution 3 standmount model at £1,079, followed by the compact floorstanding Revolution 7 at £3,299. The Revolution 9 that you see here is larger, with wider diameter bass drive units. The line-up is completed by the Center 4 centre speaker and 32A subwoofer.

Indeed the 9 is an imposing beast and looks all the more striking due to its sloping top and shiny metal surrounds on the bass and midrange drivers, plus an equally lustrous faceplate on the tweeter. As my review pair was finished in the 'cappuccino' veneer, they seemed to stand out all the more, whereas they are not quite so obvious on the white finish. They look quite good too on the piano black – which attracts a slightly higher price – but I felt they did not suit the veneered finish. You can always hide them behind the grilles if you wish.

The Celan Revolution 9's imposing, heavily built cabinet is 1,272mm tall by 374mm wide and 440mm deep, and weighs a massive 38.4kg – so handle with care, unless you know a good osteopath! The speaker sits on substantial plates that bolt to the bottom of the speaker and have either metal or hard rubber spike tips. On the rear are two reflex ports and two sets of gold-plated 4mm speaker binding posts, allowing bi-amping or bi-wiring. There is also an extra set of terminals that provide a +2dB treble boost – more of which later.

A 3-way bass reflex design, all the drive units in this speaker are Heco's own. The new, fourth-generation 25mm polyfibre Fluktus dome tweeter has a corrugated front plate to improve dispersion, and a double magnet drive and lightweight PFC dome is said to ensure high efficiency and good resolution. The 165mm midrange driver and twin 200mm woofers use Heco's Kraft paper cones, said to provide low weight and high self-damping. The wood fibres are from Nordic pine timber as only these, says the manufacturer, have the strength required. This pulp is then mixed with 5% German-produced wool fibres, which interlock with the wood pulp fibres to form a densely conjoined weave when they are pressed into the required shape under high pressure.

The midrange unit has a newly developed POC dust cap and a coated fabric surround, while the woofers have a long throw surround and a high-capacity voice coil. Both midrange and bass drivers have a multi-ventilated cast aluminium chassis. The crossover is said to use high-quality, close tolerance components, crossing over at 230Hz and 2.8kHz in the upper bass and midband, respectively. The MDF cabinets each have three internal bracing panels.

With sensitivities between 90dB (Revolution 3) and 93dB (Revolution 9), this range is ideally suited to lower power valve amps. I was very keen to see how they performed with the two valve amps I had to hand at the time of my review – the affordable Leben CS300XS (EL34 pentode push-pull, 15W) and the high-end Audio Note Tonmeister Phono (300B triode single-ended, 8W), which are favourites of mine. My sources comprised an Audio Note CDT-Five CD transport with DAC5 Special, an Audio Note TT3 turntable with PSU3 power supply, Arm 2 and Io1 cartridge playing through the AN-S9 transformer.

As far as placement goes, the owner's manual recommends that the speakers should be sited at least 20cm from a rear wall and 30cm from a side wall. In my room, after some experimentation, I found that 30cm from both worked best, with the speakers toed in towards the listener. Any closer to the rear wall upset the balance, making them slightly bass heavy. I tried the +2dB tweeter setting, and while it clearly lifted the top end, in my view, it disturbed the balance. It may work in some rooms, but I preferred the speaker set flat.

THE LISTENING

This is a fast, agile and enjoyable large loudspeaker with impressive balance and poise. Via the Leben amplifier, Peter White's superb cover of Johnny Nash's I Can See Clearly Now was immediately impressive. Percussion was crisp, and the nuances of White's guitar were laid open without any blurring or harshness. The lilting bass line was conveyed with great authority and tunefulness, and when that weighty bass line kicked in, the various instruments and their contribution to the song were not lost.

One album that I am growing to love more over time is The Secret of Climbing from Canadian guitarist and singer/songwriter Stephen Fearing. This special recording has an intimate atmosphere and features some gorgeous Manzer Cowpoke guitar work which came over with great power and body via the Hecos. On Red Lights in the Rain, the Revolution 9 conveyed this beautifully; vocals were delicate, articulate and lacked any harshness or glare when Fearing really pushed a note. Both the impact and emotion of the song were fully captured by these big boxes.

Another chance for the Revolution 9 to show off its power and control came with Bruce Springsteen's Racing in the Streets, from his superb Darkness on the Edge of Town LP. This is an emotionally charged and atmospheric masterpiece, and as the first few bars of the piano got underway in the intro – joined by Springsteen's soulful vocals – it was clear that this speaker was the boss. I loved hearing the body of the piano and the emotion of the vocals. Percussion and drums were also tight and crisp, and when that deep, driving bass line kicked in, it was super tuneful. All of which makes for a loudspeaker that plays music very fluently and expressively.

This is especially apparent with well-recorded programme material, such as Sarah Jarosz's Build Me Up From Bones. This track has beautiful vocals and an unusual backdrop to the mandolin of cellos and pizzicato and bowed violin. The big Heco absolutely nailed her vocals, conveying all the breathiness and emotion that she packs into every note. At the same time, her mandolin playing was conveyed with forensic detail. The cello had great weight, and moved well, while the pizzicato and bowed violins were equally deftly portrayed. This song has a lovely rhythmic ebb and flow, which came across very well.

THE VERDICT

Heco's big Revolution 9 proves to be a lot of loudspeaker for the money. Well made and finished, its quality is evident in even the smallest details – but don't be fooled by the slightly 'blingy' styling, as it does not sound brash and in-your-face. Quite the opposite is true, as this is a very nicely balanced floorstander with no unpleasantly harsh edges. Dynamic, detailed and articulate, it plays music with poise and aplomb. So I strongly recommend you audition a pair, especially if you're looking for something to breathe life into a relatively low-powered valve amplifier – together, they will make a formidable combination.

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