Since 1991, Kudos has been building loudspeakers according to an elegant philosophy – keep it simple!
It’s a very sound basis for speaker design, if you will excuse the pun. Basically, it means don’t add anything that is not essential. Some designers add more and more crossover components to even out and flatten the frequency response, which can be to the detriment of the sound and the music. But conversely, if essential parts are removed ad extremis, then the same thing can happen. So, there is usually a sweet spot, where everything comes nicely together.
The Cardea Anniversary Super 20 is actually the top model in the Kudos range of two-way floorstanders, priced at £855 above the Cardea C20. It features higher quality internal components (see page 73), such as generously over-specified inductors, resistor, and silver/gold/oil capacitor, all from the German component specialist Mundorf. These all increase the build cost and hence the selling price.
A cursory glance at the Super 20 does not reveal anything remarkable from the outside. There’s a very nicely veneered and lacquered, 18mm MDF, internally-braced cabinet (natural oak in the review samples). Removing the woofer, revealed that the cabinet is damped in the top section behind the woofer by 5mm thick damping pads to control panel resonances. There is also acoustic foam here to deal with internal reflections. There’s nothing radical or high-tech here, just good practice well applied. There’s a large 65mm diameter port (damped by stretched open weave cloth) firing into a slot between the base of the cabinet and the plinth. The large port diameter reduces air velocity, minimising port compression and noise due to air turbulence at high volumes. The slot exhaust means there is no worry about nearly obstructions (rear wall, or curtains for example) obstructing the exit. It should make for easy placement in the room.
The plinth is a combination of MDF, steel, and damping, forming a constrained-layer damping sandwich, and it is very inert. The spikes supplied for review were the very nicely finished stainless steel ones from Track Audio. It must be said that these caused virtually no visible damage to the carpet, due to their special profile, and so get top marks from my wife! The small cloth covered MDF grilles are held in place by magnets, which attach to three of the drive unit fixing bolts, thus eliminating unsightly grille fixings.
Drive units are both made by SEAS, to Kudos’ specifications. The woofer is a nominally 180mm spec. paper pulp-coned unit, on a die-cast frame. It has a distinctive solid aluminium phase plug (with Kudos Logo) fixed directly to the central pole, in place of the traditional dust cap. This has become something of a Kudos trademark, but is not just there for visual effect: it avoids any possible colorations due to air trapped under a dust cap, and also provides additional heat sinking.
The voice coil is 25mm in diameter, overhung to give a long linear throw. The former (on which it is wound) is finished in black to aid heat dissipation. There is also a copper shorting ring in the magnet system, to reduce eddy currents (and reduce distortion). Meanwhile, the tweeter is the high performing (and very expensive) SEAS Crescendo 29mm soft dome, and is the K2 version as used in Kudos’ Titan model. The Crescendo has six spaced radial magnets, which are claimed by SEAS to provide better ventilation and cavity damping than a conventional ring or slug magnet. A substantial machined aluminium face plate and injection-moulded zinc rear chamber ensure a solid and vibration resistant construction.
Despite the strong rear chamber, Kudos house the Crescendo K2 tweeter in its own sealed chamber at the top of the Super 20 cabinet to further isolate it from the woofer’s sound pressure.
Internal wiring is all via Chord Company cable. Only a single pair of input terminals is provided on the basis that it’s better to eliminate the metal shorting links that would be required for single-wired use (with four terminals), because the added links would degrade the sound. If customers want to use bi-wiring, Kudos can provide the appropriate terminals to order. As can be seen on page 73, the crossover components are hard wired (soldered directly to each other) and hot-melt glued to the MDF terminal panel, which really does need to be larger than usual to accommodate the substantial crossover components.
Hard wiring eliminates the need for printed circuit board copper tracks, in the process minimises metal-to-metal joints, and guarantees true star earthing. The woofer filter comprises just one air-core coil (first order), while the tweeter filter is a smaller air core coil, capacitor, and resistor (second order), which is all in line with the Kudos ethos. Such a simple crossover requires excellent drive units of course, and in particular a woofer with a very smooth frequency response.
Once I had removed the grilles, (which until their removal had caused the sound to close in and become quite boxy), it was immediately apparent that the Super 20 had some outstandingly good qualities. In particular, there are the finely woven textures audible through the midrange and treble, the deep, open, sound stage, and some fine musical dexterity. For instance, take the CD transfer of the 1957 Kingsway Hall recording of Rimsky Korsakov’s Capriccio Espagnol op34 by the LSO, Alfredo, Argenta, Campoli [originally on Decca SXL LP]. This old but delightful recording was reproduced with all its fire and brilliance. The sense of occasion was electric, like being hard-wired into the original performance, with so much texture and detail, fiery virtuosity, and drama. Clearly, the dynamic resolution of the Super 20 is to a high standard. It gave a beautifully clear, open and lively rendition, revealing every last layer of fine micro detail. For example, the castanets and triangle were reproduced clearly and brought into sharp focus, not just in their overall sound, but including their innate qualities. To use a photographic analogy, the loudspeakers are like a high grade lens focussing sharply on to the recording – no soft focus or blurring here! It was edge-of-the-seat stuff, fully involving and truly exciting, though at times I yearned for a tone control to feather some of the treble. Exciting and transparent to the recording is great, but there was also a degree of treble emphasis heightening the experience.
I went to another CD transfer, this time from an old LP Mercury Living Presence recording of Rachmaninoff’s Piano Concerto No 2 in C minor Op 18, (Antal Dorati, Byron Janis, London Symphony Orchestra). This was also reproduced with a lovely sense of clarity. The original analogue tape noise was clearly reproduced, but not in a ‘peaky’ fashion, as is sometimes the case. Byron’s piano was beautifully rendered, revealing his expressive playing: how he subtly applies pressure to the keys, to gently phrase the notes – delicately or powerfully. The Kudos clearly conveyed the lyrical ebb and flow in this unashamedly romantic piece. The fleeting cascades of notes transcended time and space, beyond what most speakers are capable of reproducing. Nuances were revealed clearly. I would personally have liked a little more warmth in the double bases and to the piano’s left hand keys, where maybe a bit more power and presence would benefit. The tweeter is particularly self effacing; detailed, yet smooth and well controlled, and though it contributes a lot to the price of this speaker it also contributes much to the overall performance.
Another CD transfer tried was from the Pentatone re-master of Beethoven’s Symphony No 2 (Kurt Mazur, Leipzig Gewendhaus Orchestra). This is yet another old recording, but this time one with a very different balance to the last two; it is recorded with a lush, deep rather distant perspective, which can sound dull and boxy with some loudspeakers. Via the Super 20s, this sounded anything but boxy. The Gewendhaus Orchestra sounded lush and beautifully textured. In the Allegro Con Brio, the fleeting strings were a delight and the double basses drove the piece along a pace. Despite the density of this recording, the stereo imagery was very good. It was obvious in this piece that the loudspeakers appear to have a very low noise floor of their own, enabling the subtler details of the music to shine through, and in lesser speakers the clutter of delayed sounds from drive units, cabinets, port, and maybe even the crossovers cause blurring and imprecision. Yes, this recording sounded remarkably good.
With Ivo Janssen playing Bach’s Well Tempered Klavier (No 1 in C Major BWV84 and in C minor BWV 847 – Void 9805), Ivo’s Yamaha Grand was set back in the acoustics, with convincingly deep perspectives. Loudspeakers can make piano sound ‘clangy’ and harsh, or muffled and indistinct, but not in this case. Even in the fastest passages the notes were clearly delineated and reproduced without blurring, or running one note into the next, and the sound was clear and open.
Changing the musical genre to Miles Davis’ Kind of Blue (on Columbia Legacy CD). This is another recording with obvious analogue tape hiss, which was handled well by the Super 20. Miles’ trumpet and Bill Evans’ piano were crystal clear. Everything was audible, including the delightful interplay between these two artists in ‘Freddie the Freeloader’. These speakers seem to wring the last ounce of musicianship from this old recording, but they take no prisoners in the case of poor or bright recordings.
Playing ‘The Sea’ from Morcheba’s album Big Calm, Skye’s voice is clear and focussed, though maybe a little ‘wispy’ and just lacking her characteristic husky quality. The deep, solid bass lines which characterise this track and help give it structure were restrained. Likewise, with Kraftwerk’s ‘Tour De France’ from their live recorded CD Minimum Maximum, the audience was very clearly reproduced, synth harmonics were very clear, although the bass lines which drive this piece along seemed slightly restrained. Phil Collins’ CD Going Back comprises re-renditions of 60’s classics that rely on a steady bass beat, which lacked drive on the Super 20. A few more rock and pop tracks revealed that the bass delivery of the Super 20 does not provide quite so much of a firm driving underpinning bass line as many bass reflex speakers.
Ironically, there is absolutely no lack of bass with this speaker, as my own measurements revealed. The Super 20 is quite flat down to 50Hz or so, tailing off below to -6dB in room at around 40-45Hz. Bass output does not peak, so there is no unnatural emphasis (as in some reflex designs). Port output is centred on 40Hz and is broad and well damped. The overall effect is more like a sealed box speaker, with only minor port assistance, so bass timing should be good (more like a sealed speaker than a ported one). I am tempted to suggest that the unforced bass character and balance are better suited to classical and jazz genres, where unexaggerated, evenly reproduced bass is a real benefit, but I really do not like such broad generalisations. The benefit of the bass tuning is that the Super 20 never booms and placement within the room seems to be relatively non-critical.
My tests also revealed a step upwards in output of approx 2-4dB, (depending on the measurement method – anechoic or in-room) between the mid range and tweeter units. Reflections from room surfaces fill in some of this step, but I believe this explains the perceived balance, because it will also influence the perceived level of bass. Apart from this, the speaker’s output is very smooth and even, clearly showing careful design. Derek Gilligan of Kudos told me there is a deliberate treble lift, because they are designed by listening, as opposed to measuring. So, to be honest, I was not at all surprised to discover this trend in my measurements.
In conclusion, the Super 20 is like an analytical tool, which dissects each recording so that the differences between tracks on an album, or between orchestras, or even venues, are highlighted, and layers of subtle musical minutiae are revealed. Indeed, while playing a selection of Blue-ray High Fidelity Pure Audio tracks, and high resolution computer files via USB DAC, the dramatic improvements in realism were blindingly obvious. So that ‘excellent’ with CD, became ‘Wow, that’s amazing!’ with hi res.
That is of course what a good speaker should do, but it can be a double-edged sword. Apart from highlighting recording differences and musical clues, the loudspeaker is also particularly sensitive to cables, clearly revealing improvements. So careful component matching will be critical. It is not your average ‘plonk it down and connect it’ kind of product. In summary, the Kudos Super 20 is indeed a remarkable loudspeaker, which will win many friends for getting to the very heart of the music.
- Type: 2 way, bass reflex
- Recommended Amplifier Power: 25W – 300W
- Sensitivity: 88 dB
- Nominal Impedance: 8 ohms
- Frequency range: 30Hz – 30kHz “AIRR” (Average In Room Response)
- Tweeter: 29mm Kudos Crescendo K2
- Dimensions: 925mm x 200mm x 270mm (hxwxd)
- Finishes: Black oak, cherry, oak, walnut, rosenut, satin white
- Price: £4,250 per pair
Manufactured by: Kudos Audio
Tel: +44(0)845 458 6698
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