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Yamaha CBX-K1XG

MIDI Sound Keyboard By Derek Johnson
Published May 1996

The CBX‑K1XG looks suspiciously toy‑like, but conceals a versatile GM sound source and a host of MIDI controller functions behind its simple exterior. Derek Johnson nearly loses it down the back of the sofa...

Back in September 1995's SOS, Paul Nagle briefly mentioned a new MIDI controller from Yamaha during the course of his MU50 sound module review. The CBX‑K1 was a mini‑keyboard aimed at desktop musicians and multimedia applications, providing easy note input for computer users at a low cost. Less than a year later, Yamaha have updated and improved it, and also coined an ungainly epithet for such a compact keyboard: the CBX‑K1XG. Significant enhancements include a computer interface, a sustain pedal socket, and — best of all — a built‑in General MIDI/XG sound source, complete with speakers and audio input.

Light Funtastic

Aside from the speakers, 3‑digit LED display and redesigned labelling, the CBX‑K1XG is, physically, almost identical to its predecessor: the casework, tiny keys, octave shift buttons (four octaves up or down for the full 128 note MIDI range), pitchbend wheel and assignable controller are the same. It will even run from batteries. The keyboard itself is velocity‑sensitive, and can transmit virtually any MIDI data on any channel, including program changes (with Bank Select); controller information (including Aftertouch) via the assignable wheel; sequencer control messages (Stop, Start and Continue), and so forth. The CBX‑K1XG isn't festooned with editing buttons; instead, the actual keys on the keyboard double up as function/parameter select buttons and decimal/hexadecimal numeric keypad. Accessing these functions and altering their value is done in a none‑too intuitive manner, by pressing the purple Shift button and one of the keys, entering a value, and pressing Enter. See 'All Keyed Up' for a list of the keyboard's functions.

In addition to MIDI In and Out sockets, connections include stereo headphone and input sockets (both on mini jacks), and a pair of phono outputs. Note that while using headphones disconnects the main speakers, using the phono sockets doesn't — but sticking a jack into the headphone socket sorts this out. Finally, there's a PC/Mac interface and a power supply socket. Predictably, power comes from an external supply.

Tiny Tunes

The CBX‑K1XG's integral GM/XG sound module is actually a version of Yamaha's DB50XG PC daughter board, which is itself a slimmed‑down MU50 GM/XG sound module. It provides 759 individual AWM2 sampled voices, 16‑part multitimbrality, 32‑note polyphony, and three independent effects sections with a total of 64 effect types. You can edit voices and effects, and since the CBX‑K1XG can send virtually any kind of MIDI data, you can do this from the keyboard itself (the manual provides comprehensive MIDI spec). Be warned, though: editing is fiddly, since you have to use that aforementioned combination of Shift button and keyboard keys. Sonically, the CBX‑K1XG can hold its own with the best GM modules, and has all the extra sounds provided by Yamaha's XG‑enhanced GM. The sound set is highly playable, and works really well with the average GM Standard MIDI File.

Your Flexible Friend

The CBX‑K1XG has lots of pluses, but there are a few minuses to point out first: volatile memory, bulky external PSU, and fiddly editing — the shift‑key‑value‑enter system is not the most accessible I've seen. In their defence, Yamaha have been pretty clear in labelling the front panel, and without adding lots of extra buttons, it's hard to see how else they could have made the CBX‑K1XG so functional. The manual, while informative, could be heavy‑going for the beginner.

However, I was surprised at how playable the keyboard was: there's no escaping its smallness, but the velocity sensitivity makes a real difference. In addition, the CBX‑K1XG doesn't take up much space on the desktop, and comes with a MIDI interface and decent sound source ready‑installed. In view of all these points, I think this instrument offers good value for money: a GM sound module of this standard would set you back between £250 and £350, while even the cheapest controller keyboards cost around £150 and don't always have the full controller features of the CBX. This makes its retail price of £339 look very reasonable.

I wouldn't expect a classically‑trained pianist to choose the CBX‑K1XG as a first MIDI instrument, but it does have a definite market nevertheless. It would be an ideal purchase for the desktop musician at whom it is so obviously aimed, and other potential purchasers include musicians on the move — just add a laptop and your favourite sequencing software — and schools. All in all, a pleasing little keyboard that packs a bigger sonic wallop than its size would seem to indicate.

All Keyed Up: Keyboard Functions

The following functions are available using the Shift button plus keyboard keys to change settings and send MIDI data:

  • Sequencer controls: Stop, Continue, Start, Tempo.
  • Program controls: Bank Select, Program Change.
  • Reset: GM Off, Sound Off, XG On.
  • System: Merge On/Off, MIDI Channel, Fixed Velocity.
  • Wheel Assign: RPN, Controller, NRPN, Drum Number.
  • Transpose up/down.
  • Hexadecimal keypad: Numbers 1‑F and 0.
  • Hexadecimal Enter.
  • Decimal Enter.

These are what Yamaha call Group A functions; a secondary collection, Group B, can be accessed by pressing Shift and Decimal Enter, and includes such functions as Song Select, Song Position Pointer, Bulk Dump Out (for sending a SysEx dump of all current settings to an external MIDI storage device), and a variety of more esoteric functions, a full list of which is provided in the manual.


  • Compact and versatile.
  • Velocity‑sensitive keyboard.
  • Built‑in PC/Mac interface.
  • Built‑in GM/XG sound source.
  • Comprehensive MIDI controller functions.


  • Keyboard too small for some fingers.
  • External power supply.
  • All parameters reset on power down.
  • Tinny sounding on‑board speakers.


Definitely a niche product, but given the number of PCs and Macs owned by musical wannabes, this could be a large niche. Anyone with cash and space restrictions who requires high‑quality GM sounds, a MIDI interface and a usable, velocity‑sensitive MIDI keyboard should look no further.