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Quadral Vulkan VIII
p2 Sound Quality
p3 Conclusion
p4 Measured Performance
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Quadral Vulkan VIII loudspeaker

From Hi-Fi World - April 2012 issue

 

Volcanic

 

quadral-vulkan-viii-site

 

From Quadral comes the massive Vulkan VIII loudspeaker. German for volcano, would it live up to its fiery name, Noel Keywood wonders?

 

Vulkan with a ‘k’ is German for volcano, harking back to the Roman God of volcanic fire, Vulcan. Would it set our listening room alight I wondered? How many Globes would it get if it did? Hmmm...


As a loudspeaker designer myself I know the various approaches and their justifications and can sense what the designers of the Vulkan VIII had on their mind with this towering monster, one that stands 1.27 metres high no less. A metal coned midrange and ribbon tweeter will together sound ‘fast’, but it is difficult to get equivalently ‘fast’ bass able to keep up and you end up with a two part loudspeaker, sound wise. Deep bass can be wrung from ports, and plenty of it if a couple of 8in drive units are used, as in Tannoy’s DC8T.


This solution never gives the bass slam of a big 12in or 15in bass unit in a giant cabinet. It is something many crave once they have heard it, usually from big, old loudspeakers bearing resemblances to a broom cupboard. Having lived with Leak 2075s and then Leak 3090s, followed by Tannoy Yorkminsters I know a thing or three about this broom cupboard experience. It’s like having one thrown at you!


However, use a 12in bass unit in a loudspeaker and you are faced with a monster in the lounge. Just look at contributor Adam Smith and his Leak 2075s, with their Leak Sandwich 13in bass units. Great aren’t they! But the front of such a loudspeaker stretches out to broom cupboard width to accommodate a 13in sandwich bass unit and not everyone is happy about the visual result, namely the rest of the family. Also, wide front baffles image badly.


Faced with this problem manufacturers are tempted to put the bass unit on the side of the loudspeaker, but then it cannot handle anything above 100Hz. Quadral use a massive 32cm bass unit (12.6in) in the Vulkan VIII, mounted on an angled baffle and vented though front and side panels. This approach allows them to keep the front baffle acceptably narrow, just 29 cms, which lessens the sense of looming presence. And you’ll be happy to know that a 32cm bass unit still has more cone area than two 8in (20cm) bass units, giving more slam.

So although you cannot see it, the big Vulcan VIII is a three way, and a heavy one too, weighing 55kgs apiece. It is ported and you cannot see this either, because the port is underneath, firing downward. A plinth holds the cabinet just above the floor to provide breathing room, as it were, with a rear facing vent. So the Vulkan VIII is a three-way with reflex loaded '12in' bass unit, all cleverly arranged so as not to look like a broom cupboard. Big bass units consistently produce low distortion, our measurements show, and give cleaner, tighter bass than struggling 8in units, so the Vulkan VIII has potential.


Quadral go to all this trouble to engineer in bass that can keep up temporally with their 17cm Altima midrange unit and this in turn must keep up with their large ribbon tweeter. The Altima midrange uses a “blend of the three light metals, aluminium, titanium and magnesium” they say, to avoid the metallic coloration of aluminium cones, and the sluggishness of plastic cones.


However, it is the ribbon tweeter that sets the pace, because these things are fast, as well as clean. The Vulkan VIII has Quadral’s own design, newly enlarged to go lower and louder, +10dB louder they say. All the ribbon tweeters I have used in the past reached down to 4kHz, leaving an awkward gap to be filled by expecting rather too much from the midrange unit. Quadral’s ribbon reaches down to 2kHz they say, so no gap! Big ribbons that go low have been done before, notably by Celestion’s Graham Bank, but they are difficult to make and expensive.

There appear to be five different finishes but ours came in deep gloss black. The rear connecting panel has sturdy screw terminals that allow bi-wiring and accept bare wires, spades or 4m plugs. As you might expect, the Vulkan is very well built and finished.


SOUND QUALITY

 There is no running preface to sound quality because – thankfully – our review samples came run in. We ran them for 24 hours with Monitor Audio’s De-Tox disc and I started listening with our Icon Audio 845 valve monoblock power amplifiers set to 4 Ohms. In this case bass seemed a bit one-note and boofy and not quite right. As there is an input blocking capacitor on the Vulkans this may well need to ‘see’ a low source impedance, which it would not with a valve amplifier. Swapping over to our tight, dry sounding Musical Fidelity AMS50 pure Class A transistor power amplifier largely cured these woes. In our listening room I also found it better to use the Vulkans with bass unit facing outward, rather than inward as in our initial setup. So positioned, and firing straight down the room, is how the Vulkans were reviewed.


Quadral put effort into getting an evenly balanced loudspeaker, a property I greatly value, and the Vulkans follow their philosophy closely. With no peaks or dips or artificial emphases, our measurements show, they sounded deliciously smooth and natural, rare with ribbon equipped loudspeakers whose designers like to raise treble just to demonstrate the arresting properties of ribbon treble units – enormous, speed, detail and incision. Quadral have resisted this, so I found I could enjoy their lovely ribbon unit without having to wince at sonic lances, for ribbon tweeters to can be challenging if too forward. The midrange unit integrates well, with no change of character to mar crossover, and bass has been engineered to be tight and fast, rather than large and obvious. For such a large loudspeaker bass energy was held in strong check; the Vulkans are not Tannoys! Doing this helps the loudspeaker play a bass tune, by keeping slow-to-decay  subsonics in check.

Moving up and down in front of the loudspeaker showed vertical integration very good out at normal listening distances – rather better than dome tweeter loudspeakers. Best ear height was just below the ribbons but the change in sound balance was not great as I moved further up or down. Listening on the central axis of the ribbon unit, meaning high up, did add in the hiss of strong high treble at times, but only from CDs possessing a lot of high frequency content.


The opening drum strike of Angelique Kidjo’s ‘Agolo’ was muted in terms of subsonic content. It came and went quickly, sounding powerful but well damped. There was none of the resonant boom that I often hear from ported loudspeakers. The ribbons set out a wonderfully clear, sharply etched sound stage on which every instrument had a perfectly defined place – a real strength of ribbon tweeters, and one the big Vulkan exploits beautifully. With the ribbons sitting high, 110 cms above the floor, the sound stage has a celestial quality, something I always enjoy. And with plenty of treble bouncing off side walls the stage sounds wide, even though we use big acoustic damping pads on our walls as part of the room’s acoustic treatment. Maracas rang out clearly and fine metallic percussion instruments hung in space beautifully.

Swathes of intricate detail accompanied the backing singers and the layered instruments of Kidjo’s backing band, bringing a lovely busy feel to proceedings. The Vulkans sound clean and distortion free, yet although they move along at a brisk pace, they sound relaxed. Able to resolve strong dynamic contrasts this makes for a loudspeaker that is fleet of foot yet engagingly dynamic too.


Turning volume right up with Adele’s ‘Rolling in the Deep’ the Vulkans became wickedly loud but stayed relaxed and clean, nearly blowing me back over the settee. Kick drum was both tightly controlled and powerful too. However, the loudspeakers have a slight boxy thud at times, when pushed hard like this, and here I strongly suspect the big bass cones are letting through box colour, not helped by a nearby baffle behind them. This apart though, bass comes over as tight, dry and powerful, giving the big Vulkans a solid kick. Adele’s vocals were perfectly formed and had all the power expected from them.


Listening to Nigel Kennedy playing Vivaldi’s ‘Spring’ brought up an interesting discussion with Rafael Todes, of the Alegri String Quartet. Nigel’s Stradivarius came across as big and solid in nature, smooth and deeply detailed – impressive by any standard. There was not the phasiness so common on dome tweetered rivals, doubtless due to the ribbon tweeter. My only small concern here was that his violin lacked the timbral signature of a wooden bodied instrument, with gut strings; it was a shade too metallic in nature. I was using Eminent Technology LFT-16s as a reference here, for their ability to show that such properties do exist in the recording. Rafael liked the sound of the Vulkans but agreed that there was some “sheen” in the sound as he put it, having owned a Stadivarius like Nigel's for some years. I also learnt, by the way, that the top strings of a violin are metal wrapped to preserve their life, or they wouldn’t last more than 30 minutes. The English Chamber Orchestra sounded large and lush behind Nigel, instruments well differentiated from each other in a clean sweep behind him.

The Vulkans captured the deep, resonant tones of Jackie Leven singing  ‘Desolation Blues’ and made him as large sounding as he was in life. They saw right into this recording, surrounding him with floods of fine detail, as well as cues into the surrounding studio, in a performance that came over as easy, unforced yet powerful. Deep male vocals highlight box colour though and again I became aware of some slight boxiness, almost certainly coming from the big bass unit. It was a relatively minor effect though and unintrusive.


CONCLUSION

Big loudspeakers often have strong characteristics, massive bass and excess treble too. Quadral have tried and largely succeeded in producing a sound of large scale but great control in the Vulkan VIII – not properties that are easy to combine. It runs cleanly from the highest highs down to the lowest lows without unnatural emphasis over the entire audio range. This is a dry, controlled, finely balanced but accurate loudspeaker. With copious dynamics, it is big hearted too, yet goes from loud to soft with an alacrity that is rare. This gives it a smooth ability that defies other loudspeakers.


With so much effort in the design, including a good understanding of how to tie together the various components in subjective terms to achieve a cohesive whole, rather than a disparate set of sonic parts, the Vulkan VIII is one impressive loudspeaker. If you want to hear a thoroughly modern, well engineered loudspeaker, with fantastic imaging and amazing detail, plus deep, fast bass, this is one you should hear. I'm happy to report it didn't burst into flame either, so it gets full five globes. Vulcan may not be so happy – but I was.

 

verdict five globes
 A massive sound but one that is both fast and accurate, with delicious detail and imaging.

 


QUADRAL  VULKAN VIII £6600.00

+44 (0)1785 748 446

www.quadralgb-ie.co.uk

 

FOR

- precision sound stage

- clear midband

- tonally balanced

 

AGAINST

- some sheen

- small box colour

 


MEASURED PERFORMANCE

Our pink noise frequency response shows the Vulkan VIII has an impressively flat frequency response (green) with the measuring microphone vertically aligned midway between ribbon tweeter and midrange unit, putting it at typical ear height. Vertical dispersion of the ribbon is sharply defined so a little higher restores treble above 10kHz, whilst on the tweeter’s central axis treble rose to +7dB at 10kHz (grey trace) – a large rise. Although vertical dispersion is constrained, like most ribbon tweeters, lateral dispersion is smooth and wide, so Quadral’s big ribbon throws quite a lot of treble energy out into a room and this will give the Vulkan VIII a bright demeanour, even though the on-axis response may seem to suggest otherwise (depending upon where the ear is).


At low frequencies the bass unit reaches down to 70Hz and the large underside port takes over below this frequency, peaking at 30Hz our red trace shows. This puts a lot of bass energy into the room, the port being a huge drainpipe affair (large ports produce less distortion). Bass does not peak up and is in good balance our response measurement shows. A decay graph showed low coloration except for an overhang at 80Hz.


Sensitivity was very high, the Vulkan producing 92dB sound pressure level from one nominal watt of input (2.8V). In fact, with a very low impedance of 5 Ohms overall they consumed more power than one watt, but they need little power to go loud all the same, 40W is enough. An infinite DCR value suggests Quadral are using an input capacitor. Our impedance trace shows the loudspeaker is almost perfectly resistive and an ideal amplifier load, so it is not difficult to drive.


The Vulkan VIII is a relatively accurate loudspeaker providing it is listened to just below the ribbon tweeter. It will have a bright character all the same, but should sound quite dry in its bass. NK

 

 

FREQUENCY RESPONSE (what it means)

quadral-vulkan-viii-fr1

Green - drive unit; Red - port; Grey - tweeter axis

 

IMPEDANCE (what it means)

quadral-vulkan-viii-z

 

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