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Kiso Acoustics HB-X1 standmount loudspeaker

Kiso Acoustics HB-X1 standmount loudspeaker

Some years ago, we had a pair of the fascinating Kiso Acoustics HB-1 (on their original stands) in for review. That review never came about – there was some behind-the-scenes dispute over those stands – but we did get to play them at one of the last Manchester audio shows to very great effect. The new HB-X1 builds and extends on what the HB-1 did, and we jumped at a chance to finally put one through its paces.

Kiso Acoustics is a Japanese company, a side-project if you like from the cartridge makers (and one-time preamp experts) Lyra, in association with visionary loudspeaker designer Toru Hara. It is a two-way ported standmount loudspeaker of diminutive stature, as it is about the height of a BBC-designed LS3/5a, but narrower, and this plus the sloping back means significantly less cabinet volume. The size of the speaker limits the size of the drive units in the loudspeaker, with a 17mm tweeter in a horn made from ebony, and a 100mm mid/bass unit. That’s 2/3rds of an inch and just under four inches respectively! Despite these diminutive drivers, Kiso Acoustics claims a frequency response from 40Hz-30kHz.

Part of this extended (for so small a speaker) frequency response comes down to the cabinet. The cabinet itself is reminiscent of a guitar, and those with good audiophile memories might note this has been done before. Onkyo teamed up with Takamine to deliver the D-KT10 loudspeaker of 2007. This speaker shares the same designer, the same basic shape, and not much else. If you were to compare the HB-1 with HB-X1 from the Kiso stable, you’d find a very slightly larger base (7mm to be precise) and inside that base a crossover filled with high-grade Mundorf caps.

, Kiso Acoustics HB-X1 standmount loudspeaker

The ‘HB’ in the name is derived from the rōmanji Japanese word ‘hibiki’, which translates to ‘resonance’ (‘Hibiki’ is also the name of Suntory’s extremely nice blended whisky, and I have to confess that – before it became punishingly expensive to drink in the West – on occasion, I have been pleasantly ‘resonated’ on the stuff). This idea of ‘hibiki’ is fundamental to the design of both Kiso models (and the Onkyo design), in that the cabinet is designed to be actively resonant, rather than ‘dead’. The logic is that an acoustic musical instrument uses its resonant chamber to create its tonality, tonal colour, and (ultimately) volume. A perfect – and entirely apposite in this case – example of this is the sound-box of an acoustic guitar: Yamaha makes a range of ‘silent’ classical guitars, which have the head, nut, neck, bridge and tuning pegs of a nylon-strung guitar, but with the upper and lower bouts of the sound-box replaced with an open frame and a piezo-electric pick-up. Unless you plug this guitar into an amplifier, it is almost completely silent.


Why is this guitar analogy apposite in the Kiso HB designs? Because the enclosure of the cabinet is not only designed along the same basic lines as the upper bout of an acoustic guitar, but also built by guitar luthiers. Lyra’s side-project is also a side-project of Takamine’s custom shop, and the results speak for themselves in the flesh. If you weren’t lucky enough to see the HB-1 at our Manchester presentation, or have seen them demonstrated at another show, and want to know how refined the HB-X1 looks in real life, go to a prestige guitar shop, and ask the assistant to show you what they think is the most beautifully finished acoustic guitar they have irrespective of cost, and you should get an idea of what the Kiso is physically like. In short: it’s extremely pretty, in proportion, finish, and detail; and when the light hits it in the right way it’s almost painfully beautiful, in the way only a hand-crafted musical instrument can look.

, Kiso Acoustics HB-X1 standmount loudspeaker

The Kiso sits on eight little clear gel insulators, and ideally comes to rest on tall stands. This was the sticking point in the HB-1’s failure to make it to review – Kiso makes its own ‘Podium’ stands, but the preferred option is the Vibex HB-X1 stands, built by the Spanish distributor, which comprise two carbon-fibre tube uprights with metallised polymer ‘K-material’ top and baseplates. This results in a stand that is light, rigid, extremely inert, and very expensive. You could almost say the stand does to the Kiso what a guitarist does to the sound of an acoustic guitar; adding a rigidity and support to the soundbox without constraint.

The guitar-like enclosure of the Kiso is not simply for looks. It’s an intrinsic part of the design, and – unlike practically every loudspeaker you’ll ever try – the cabinet is actively resonant. This means at some point you will place your fingertips on the cabinet, like Mr. Spock attempting a mind-meld, while the music is playing. The feedback you get from this tactile joining is fascinating, as you can feel the resonance of the music move across the cabinet, dancing beneath your fingertips. It’s like you can feel the music being created, and not just hear it. Trying this with friends and industry types alike elicits a similar response through out; embarrassment at fondling a loudspeaker, followed by puzzlement, then the realisation of what’s happening, followed by the broad smile. It happened every time.

As befits a reviewer doing somewhat loony things in search of more words, I put in a set of earplugs in an attempt to actually ‘feel’ the music under my fingers using the Kisos; I could, but my proprioceptive language skills in this respect are not well developed, so I couldn’t actually ‘hear’ the music through my fingers. However, it makes you appreciate just how profoundly deaf musicians (Beethoven and Evelyn Glennie spring to mind) can still compose and play. My admiration for such people only increases at the attempt, though. Continuing to channel Mr. Spock… fascinating!

The Kiso speakers naturally require good upstream equipment, but more significantly they need to be placed farther than usual apart, and at least 40cm from the rear and side walls. Curiously, they spring to life in rooms far larger than you might expect given the size. This is one of the very clever aspects of the Kiso; that on-paper 40Hz seems impossible given the size of the loudspeaker, but in the right room, you’ll think it’s understatement and suspect the speaker goes deeper.


Ultimately, of course, a small loudspeaker has limits on what it can do, and the Kiso HB-X1 is no exception. It doesn’t break the laws of physics then, but it waterboards those laws a little so they give up their inner secrets. That said, bass is deep and potent, not simply for a loudspeaker this small or for on-paper measurements of this kind, but simply deep and potent. The Kiso relies on the simple fact that most acoustic music doesn’t have a monumental amount of energy in the sub-40Hz region, and what the Kiso delivers is enough for most people. In listening to Mitsuko Uchida playing Beethoven’s Piano Sonata No 30 in E [Philips], you hear the beauty of the playing and the delightful tone of the piano, and you barely notice that the last octave or so of the piano is less potent than the rest. And that’s because Beethoven didn’t write a great deal of that sonata with heavy left-hand action. In fact, you begin to look at music not in terms of the bass that’s missing, but more in terms of just how much bass goes into most music, and the true answer is actually ‘not that much’. OK, if you listen to a lot of organ music, dubstep, or heavy opera, the HB-X1 is off the shopping list, but if your musical tastes view these deep bass explorations as a little ‘showy’, then the Kiso might just be ideal. So, while fast-paced bass transients like ‘Chameleon’ by Trentmøller [The Last Resort, Poker Flat] fare surprisingly well, they do so by not triggering those cavernous sounds. But, probably if you are going to be a Kiso owner, that will not matter one iota. You are past that.

, Kiso Acoustics HB-X1 standmount loudspeaker

I think it’s the dynamic range that is so captivating in the Kiso HB-X1: more so than the almost point-source imaging, which should be the main point of the speakers. Yes, the loudspeakers image beautifully, but a lot of loudspeakers image beautifully. What’s rarer is a loudspeaker that has the kind of effortless dynamics that are normally found with horns (or the real deal). This is not even a volume ‘thing’, because although the Kiso goes loud for a small box, it’s not a headbanger. Instead, play some classic jazz – ‘Love For Sale’ on Somthin’ Else by Cannonball Adderley [Blue Note] – and the dynamic freedom just gives you a sense of musicians at the top of their game riffing off one another, rather than a cool rendition of a well-worn jazz staple.

There’s one aspect of the Kiso sound that sets it apart from so much audio: it’s believable sounding. This transcends any breakdown of the music into its component parts and instead focuses on the music as an organic whole. But where other loudspeakers have some kind of coherence, the Kiso has more, and it really only can be called ‘believable’. This is an uncanny aspect of the loudspeakers, and it manifests in a peculiar – but oh so predictable – manner. The listener sits in front of the loudspeakers, liking what they hear, then turns away, and almost immediately performs a comedy double-take. A kind of ‘huh?’ moment as they hear the size, scale, and believability of the loudspeakers, only recently divorced from the physical size of the loudspeakers. I’ve seen people take four or five attempts to leave a room where the Kiso HB-1 or X1 is playing, each time turning away from the loudspeaker, only to turn back to listen to those real and believable sounds.

Once again, this believable sound tends to be heard with acoustic material rather than powerful rock or electronica – but there are a lot of speakers bigger and (on paper, at least) better than the HB-X1 in terms of frequency response and headroom, but in terms of sheer tone, of the ability to sit for long periods listening to these loudspeakers, and that abject sense of sublime musical communication from one instrument to another, the HB-X1 can’t be beat, no matter how big or how expensive the loudspeaker.

The Kiso HB-X1 is the point where reviews run out of road, and personal, individual listening becomes uppermost. The person who has never heard the Kiso will stumble at the price tag, no matter how purple the prose about how it sounds. However, the person who has heard the Kiso will stumble at how a speaker the size of the HB-X1 does what it does. Both will probably swear about the price, but where the former will decry such a speaker on moral grounds, the one who has heard it will be swearing about the deep hole the Kiso will make in their bank account.


It’s hard to write about the HB-X1 without making the loudspeaker sound flawed. It’s expensive, it doesn’t plumb the bass depths, it only comes in the one finish, it won’t play at high output, and it breaks every rule in the loudspeaker cookbook. And yet, listening to the Kiso, it dawns on you that none of those things matter. This is the kind of loudspeaker that does one thing (the small speaker that doesn’t sound small) well, but it just happens to do that one better than every other loudspeaker on the planet, and the more you listen, the more you are drawn into how the Kiso plays music.

, Kiso Acoustics HB-X1 standmount loudspeaker

The Kiso Acoustics HB-X1 is always going to be a niche product. It’s a small speaker for a big room that sounds like a much bigger speaker, and many will just buy a bigger speaker instead. But not everyone: some want big speaker sound without big speakers, and are prepared to pay big speaker money for the best small speakers they can get. And, they are exactly the people who will be seduced by the utterly captivating, utterly believable sound. Through the Kiso speakers, If You Can Believe Your Eyes and Ears is more than just an album by The Mamas and the Papas!

Technical Specifications

  • Type: Two-way bass reflex loudspeaker
  • Drive units: 1× 17mm wood horn tweeter, carved from ebony, 100cm cone
  • Rated impedance:
  • Rated sensitivity: 85dB/W/m
  • Rated frequency range: 40Hz–30kHz
  • Crossover frequency: 5kHz
  • Dimensions (W×H×D): 15×32×22cm
  • Weight: 5.2kg per speaker
  • Price: £14,795 per pair. Stands £1,795 per pair
  • Manufactured by: Kiso Acoustic Co. Ltd

URL: www.kisoacoustic.com

Distributed by: Symmetry

URL: www.symmetry-systems.co.uk

Tel: +44(0)1727 865488


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