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C-Thru Music Axis 49

Harmonic Table MIDI Controller By Robin Bigwood
Published August 2009

The piano keyboard is so widespread and familiar that we take it for granted. But, as C‑Thru Music's Axis 49 demonstrates, it's not the only option out there.

C-Thru Music Axis 49

There have been many alternative musical keyboard designs over the years. Many owere developed (and some subsequently abandoned) for button accordions and concertinas, all of them adapted to the particular musical and physical demands of those instruments. More recently, we've seen visually impressive music technology gizmos that blend pitch input with control‑surface and sequencer‑related concepts, such as Yamaha's Tenori‑On and Jazzmutant's Lemur.

And then there's C‑Thru Music's Axis 49, the subject of this review. It's a USB‑based MIDI controller that uses a 'harmonic table' keyboard — a grid of hexagonal buttons that lays out a fully chromatic, four-octave pitch range in a honeycomb‑like pattern. There are no flashing lights or touch panels here, and instead you depress the buttons a few millimetres to play them, in time‑honoured mechanical keyboard tradition.

How & Why

If you're anything like me, by now you'll be desperate to know exactly how it works — so here goes. White buttons are naturals, and black buttons are sharps or flats, just like their equivalents on a piano. However, Ds are shown in light blue and G#s in dark blue, together acting as visual anchors to aid note‑finding and orientation. Now for the pitch layout. Playing up any vertical column produces a series of ascending perfect fifths. Any diagonal climbing from left to right produces ascending major thirds, and right to left diagonals are minor thirds. As the MENSA members amongst you will already have spotted, this means that a standard major chord in root position is formed by pressing down any three adjacent keys in a right‑facing triangle shape. Want a minor chord instead? Just make that a left‑facing triangle. Ingenious! The way the layout is underpinned by neighbouring fifths and thirds also makes it easy to form major and minor seventh, ninth, 11th and 13th chords. Somewhat less obvious, maybe, is that the Axis 49 actually has two identical four-octave spans (each consisting of a 7x7 button grid) next to each other. This means that you can easily cover the whole four-octave range with each hand. What's more, the transition between grids is seamless, so playing across them follows the same rules as playing within each grid — hard to imagine but intuitive in practice. I won't go into detail about what individual scales look and feel like, except to say that all the most important ones — major, minor, chromatic, whole‑tone, diminished, blues — have logical and distinctive patterns that basically climb rightwards and up. On the Axis 49, the separate pair of buttons on the left shift the pitch range up or down by up to three octaves in either direction. Pressing them together resets the octave position to normal and sends a MIDI All Notes Off message.

Following hot on the heels of 'how?' comes 'why?'. What's the point of the harmonic table? Why bother with it? One of the major selling points is the way in which all musical keys feel the same. The fingering and shape of chords and scales are the same in C major, Eb major, F# major, or any other key you like — and you definitely can't say that about a piano keyboard. This freedom in terms of key inevitably makes you think less about the specific notes you're playing and more about the harmonic or melodic relationships within them. That's a Good Thing — perhaps the holy grail of harmonic understanding — and can help you glimpse the essential underlying structures in music of all types. You start to feel a bit like Keanu Reeves at the end of The Matrix (without the silly coat). For musicians with physical disabilities, I'm guessing that the harmonic table could prove very empowering, concentrating a wide pitch compass into a compact physical space and allowing one- or two-finger construction of fundamental chord types. The footprint of the thing is small — about the same size as my 13‑inch MacBook — and so it works well in cramped setups. Finally, C‑Thru Music claim that learning and playing the Axis is inspirational and fun, which can't be bad. Does the product stand up to the hype?

On The Table

These screens show you how the harmonic table works and how chords can be formed using it.These screens show you how the harmonic table works and how chords can be formed using it.

As a MIDI controller device with no on‑board sounds and no conventional MIDI sockets, you have to hook up the Axis 49 via USB to a Mac or PC running a DAW or a stand‑alone software synth, to get anything out of it. There's a single B‑type (square) USB socket on the rear panel, and as the Axis is class‑compliant, no drivers are required. C‑Thru Music don't publish any operating system requirements, but anything reasonably recent should do the trick — certainly XP, Vista or Mac OS from 10.3 onwards. On my Power PC Mac running OS 10.5.6, the Axis was immediately recognised and appeared in Audio MIDI Setup.

Getting started with the harmonic table is an interesting experience, to say the least. The good news is that the initial learning curve is almost non‑existent: the moment you spot the way that fifths and thirds are mapped across the buttons, and especially when you play your first major and minor chords, you feel destined to become a virtuoso in no time at all. The bad news is that taking it further is less easy and, in particular, mastering melodic intervals like seconds, fourths, sixths and octaves takes some time, as does spotting chords in inversions and voicings outside of simple root position. That's because both require a lot of hopping to non‑adjacent buttons. Fast soloing, counterpoint and independent two‑handed playing is certainly all possible, but would probably require months of basic practice before it felt remotely secure. Still, this is not so bad — I've been playing piano for 30 years and that still doesn't always feel secure! Incidentally, C‑Thru Music supply a sheet of stick‑on letter names for the buttons. I personally chose not to apply them, but I suspect they'd make learning the layout even quicker, and could be easily removed once you'd mastered it.

What's undeniable is that the Axis really is inspiring. Literally every time I played it, even when just doodling and exploring the layout, I came up with musical ideas and material that I felt were worth developing, and which were different to anything I'd have produced when playing a conventional controller keyboard. The correspondence between musical intervals and spatial relationships seem to be at the heart of this, and I'd frequently find myself exploring the harmonies produced by variously‑spaced finger spans, lines, triangles, squares, and so on. The fact that the results were initially hard to predict seemed to be an important part of the experience — you threw something at the Axis and it threw something interesting back. I was relieved to find, though, that this kept happening even as I became more proficient.

Axis Questions

C-Thru Music Axis 49

As far as I'm concerned, the harmonic table layout itself isn't really up for criticism. It is what it is — a novel and elegant concept that will no doubt drive some people into a frenzy of creative excitement while leaving others wondering what the point is. It's the implementation of it in the Axis that is really what this review is about, so that's what I'll focus on.

I'm a big fan of music technology that is simple, straightforward, intuitive and gets the job done, so in one way I'm full of admiration for the Axis 49. No LCD display, no LEDs, no menu system, no configuration options — not even a power switch. You plug it in and get on with it. But I wonder if it's a little too cut-down.

I definitely missed pitch‑bend and modulation wheels — and even a button‑based approach, as on the $60 Korg Nano Key, would have been preferable to nothing at all. The octave shift buttons are crying out to be reconfigured for these uses, but sadly their role appears to be set in stone. Similarly, there are no knobs or sliders for sending MIDI CC or other messages, and no sockets for expression or sustain pedals. I'd have loved to be able to turn off velocity sensitivity occasionally, but of course this, too, is not configurable.

The workaround for some of these absent features is to combine the Axis with another controller keyboard that has them, and use the two in tandem. That might do for some people, but as not all DAWs (and stand‑alone soft synths) allow a single virtual instrument to be driven by two MIDI devices on the same channel, it's not really a guaranteed solution. Nor is it a very pretty one, and may be even less desirable on stage than in the studio.

Next, I'm no harmonic table expert, but it didn't take long before I began to sense a few shortcomings in how it's used on the Axis. I wondered why there weren't dimples or small raised sections on, say, the D keys, so you could get your hands into position with touch alone. The same system is used on computer keyboards, and on accordions, so it's a pity it's not here. I also wished that the two four-octave grids could be separated, either sending note messages on separate MIDI channels, or becoming offset in pitch, so I could have an eight octave range available. Yet again, though, the factory spec is non‑negotiable, and presumably only a firmware update would be capable of changing it. A PDF instruction manual hidden away on www.c‑thru‑ gives a tantalising hint that it might one day be possible, and apparently there's something in the pipeline.

The Axis 49's back panel features just a single USB port for connection to a computer.The Axis 49's back panel features just a single USB port for connection to a computer.Finally, I can't ignore the elephant in the room for a moment longer: that is, cost and value. The Axis 49 retails at $495, and though it's by no means shoddily built — far from it, in fact — it feels as though it ought to cost less. Case construction is from plastic, and the key action basic and quite noisy. There are rubber feet on the bottom (of which one on my review model kept falling off during transport) but no other means of mounting, to a mic stand for example. If the asking price were around $300, I would probably buy one for myself as a fun thing to have around. But the best part of $500 focuses the mind, and the Axis falls significantly above the 'whim‑ware' threshold, at least for me.

The flip‑side to all this is that if you can take the financial hit and stop worrying about what isn't there, the Axis works very nicely in practice. During my testing, MIDI communication was 100 percent reliable and, despite sustained attempts, I couldn't produce any hanging notes caused by using the octave-shift mechanism while buttons were held down, or by playing duplicated pitches on the two grids. The velocity sensitivity is really well judged and easy to get the feel of, despite the fact that there's no weighting of the buttons. The button design generally is also nicely done — subtle contouring makes it easy to move around, and helps to prevent unwanted triggering of adjacent buttons, as long as you're reasonably accurate. And there's plenty to suggest that despite the light weight and the plastic outer case, the mechanical design is fundamentally of very good quality. Other users who've pulled Axis 49s apart have discovered quality key contacts and durable-looking action mountings.

Flexible Friend

It's a niche product, for sure, and not without its shortcomings, but there's a lot to like about the Axis. The harmonic table is genuinely inspiring, offers a real alternative to the conventional piano keyboard layout and can definitely open new creative pathways. The preset, inflexible MIDI implementation and absence of performance controls will bother some people more than others, but equally there's no doubting the device's ease of use. Whether it's really worth the asking price (especially in the UK) is debatable, but in one sense value for money is a moot point, since all other similar products are significantly more expensive. Assessed on its own terms, this is a great product, and I hope very much that it will be a success.  

The Evolution Of The Axis

The keyboard layout used in the Axis was devised in 1983 by Peter Davies, a UK‑based guitar technician and luthier, after he'd been experimenting with some music theory ideas. Although the concept of a keyboard that feels the same in all keys (a so‑called isomorphic layout) is not entirely new, Peter's was, and he christened it the 'melodic table'. Between then and the mid‑'90s, various investments in patents were made and prototype MIDI controllers produced, and in more recent years two distinct companies have emerged out of those earlier efforts. One is Davies', The Shape of Music (, and it produces very high-quality, largely hand‑made, wooden-bodied instruments known as the Opal Gecko and Chameleon. These offer weighted keyboard actions, sophisticated key velocity features and huge programmability, and come in at around the £2000$3000 mark. The other company is C‑Thru Music, owned by Peter's former business partner Andrew Llewellyn, which makes the Axis 64 and 49 models. C‑Thru Music seems to be a joint UK and US venture biased more towards large‑scale production of what they term 'harmonic table' controllers.

The Axis 64

The Axis 64, C‑Thru Music's only other product, includes many of the features that the Axis 49 lacks. It's physically much larger, it's built into a metal case, and it has a 192 key harmonic table that puts three five‑octave button grids side by side. Additionally you get pitch bend and mod wheels, two assignable knobs, and sockets for footswitches and pedals. Crucially, the Axis 64 is also very programmable — so you can set up MIDI splits and layers, pitch offsets for each grid, and even re‑map the buttons for microtonal work. What you lose is USB MIDI and bus powering — there's a USB port but that's only for firmware updates — and instead there's a conventional five‑pin MIDI out socket. The 64 is built to order, and costs about £1000$2000.

Second Opinion

I'll happily admit that my music theory knowledge is limited. As a drummer, I consider it my stock in trade to be a dunce in the note‑relationship department. So my approach to the Axis 49 is probably different from that of the typical user.

As a theory novice, the ability to randomly stab at the keys in a pattern and get a musically useful result is great. I often find that with a conventional keyboard I get stuck in annoying ruts, like only playing conjunct melodies (which go up and down the scale in steps) as opposed to skipping around the notes of the key, as in a disjunct melody.

As a drummer, I find the best thing about the keyboard to be the duplication of keys. With two sets of 49 buttons addressing the same range of MIDI notes, I have the ability to play‑in proper drum-rolls and fills, as well as double‑handed hi‑hat grooves, as you can do with two hands (and sticks). Admittedly, finger placement needs to be spot‑on to negate the need to edit spurious hits after a recording pass.

From a general user point of view, I found the Axis 49 really simple to get working. I was half expecting to have to install drivers and configure the keyboard in some kind of wacky software editor. But it worked out of the box, even taking power from the keyboard‑mounted USB socket of my Mac, to which some MIDI devices object.

On the down side, it's a shame there's not more control on the Axis 49. If you want pitch‑bend, modulation control and provision for a sustain pedal, you have to upgrade to the Axis 64, C‑Thru Music's flagship product, which is a lot of money. This brings me to my biggest gripe: the price. Granted, it's the cheapest commercially available product that offers the harmonic table layout in MIDI controller form (along with the Axis 64, of course), but at roughly three times the price of other, more conventional, MIDI controllers, it's still a bit of a luxury item. Hopefully, when C‑Thru's demand increases, they can start manufacturing on more of a mass‑market scale, then lower the price. Until then, I think I'll concentrate on honing my keyboard skills! Chris Mayes‑Wright


  • Musically fruitful and surprisingly easy to learn.
  • USB class-compliant and bus‑powered.
  • Lightweight and portable.


  • No real‑time performance controls.
  • No MIDI or other configuration options.
  • USB MIDI only — no conventional MIDI Out socket.
  • Expensive.


Not for everyone, perhaps, but this left‑field controller keyboard combines ease of use with a musically intriguing pitch layout that might just revolutionise your playing and composition.



C‑Thru Music +44 (0)845 260 5556.



C‑Thru Music +1 760 405 3951.