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Master Keyboards

Yamaha KX88

Jay Chapman explains the theory and practicality of using a master keyboard like Yamaha's KX88 in your MIDI set-up. What are the benefits it can bring? Read on to find out...

Have you looked at what's available in the Master Keyboard line lately? If you haven't you may be a little surprised to find that there has been a subtle shift in the manufacturers' views of what the average keyboard player would like to see made available in this area. In particular, the manufacturers are now beginning to cater for non-megastars (with non-megastar bank balances!) who require what one might diplomatically call a sensible price/performance ratio. Before all the manufacturers write in to say that their products have always had a very reasonable price for what they offered, let me just point out that it's what the end-users want in terms of performance that defines a reasonable price; if you give too much of the wrong sort of performance the price will be considered too high!

In this first article I shall look at the Yamaha KX88 which, to quote from the KX88 Owner's Manual, was "the first completely programmable and assignable MIDI keyboard". In some future articles I will consider the more recent devices; this article is by way of setting the scene for those who have never really looked in this direction.

The Yamaha KX88 is not exactly a new device so this article is hardly going to be a review for those eager to spend their ill-gotten gains (ie. working to get them makes you ill) on the latest gadget. In fact, it is almost true to say that dedicated Master Keyboards, as epitomised by the KX88, are becoming a thing of the past. In some circles, including the manufacturers', dedicated Master Keyboards are deemed to be something of a failure because they just didn't catch on, ie. they didn't sell... Having said that, there are different breeds of Master Keyboard and some of the latest designs differ considerably from the earlier ones. So some lessons have been learned. Let me explain...

When the KX88 first appeared I thought it looked like an item I would like to own, in all but one respect: I couldn't stomach the thought of spending that much of my overdraft on an object which produced no sound beyond the mechanical thuds of the keys striking home. Yamaha make no bones about this - on page 5 of the manual they say: "The KX88 will not produce sound by itself. Please connect it... to a TX816 or... (to a) DX7." I have visions of some poor punter with a very light wallet getting the KX88 home, plugging it in, finding no Audio Out connector, reading the above, checking the price of the TX816 and fainting dead away!

Once you start looking into this subject you find there is a mish-mash of terminology which can confuse you no end. Try the following for size: master keyboard, mother keyboard, keyboard controller, remote keyboard, sling-it-round-your-neck poseur's remote keyboard controller. (What do you mean, I made the last one up - you watch Top Of The Pops each week don't you?) Presumably these terms all mean something? Well, I'll have a shot at separating out the various functions that could be said to be typical of the Master Keyboard and then you can use whatever term you think best!


As we shall see, some of the functions of the typical Master Keyboard are (and some of them always were) provided by other devices in the MIDI network. In fact, some synthesizers provide comprehensive assignment and control functions and it is quite possible to find duplications of various functions in both master and slave synthesizers, which can cause a lot of baffled looks and head scratching! The current trend is, in fact, to design MIDI synthesizers with the extra functionality which will allow them to be sold as a combination Master Keyboard/synthesizer. In this way the punter sees the major part of the price being apparently paid for the synthesizer functionality, with the Master Keyboard stuff as a useful extra thrown in (almost) for free.

This Master Keyboard functionality should not be thought of as merely a sales gimmick, however. It is useful, particularly in live performance, to be able to assign control to a central controller that has hopefully been designed by someone who could at least spell 'ergonomics'. As an analogy imagine that whilst driving a car you occasionally had to fiddle with something under the bonnet whilst cruising along at 70 miles per hour. Not a nice thought is it; much better to have all the controls around the driver's seat!

I'll use the KX88 as an example of the dedicated Master Keyboard whilst I discuss the major elements, both physical (hardware, both computer and otherwise) and logical (provided by computer software), that such devices offer. It should go without saying that Master Keyboards have at their very heart one or more microprocessors; like most modern electronic instruments they are essentially computers being fed by, and feeding, peripherals.


It does seem reasonable that a Master Keyboard has a keyboard don't you agree!? There are other control devices, however, that do not: the Roland Octopad comes to mind as a very interesting example and sequencers and microcomputer systems in general also fall into this category.

I am discussing the keyboard component first because this is where a large part of my interest in purchasing a KX88 derived from - I still have this fantasy about learning to play the piano (don't laugh!) - see the next paragraph. It is also the point at which the price/performance ratio business got out of hand in the eyes of Mr/Mrs/Miss/Ms Average Punter and hence the reason that sales of KX88s and other similar keyboards did not exactly rocket stratospheric...

As you may have noticed the KX88 has a full length (88-note), weighted, full-sized key, touch-sensitive, piano-feel keyboard. Not to put too fine a point on it, the keyboard is a marvel. It's not quite a perfect replication because the keys don't have the full mechanism made up of the hammer, dampers and levers that a real piano has; however, compared to your average synthesizer it's truly wonderful. Oh dear, in all my enthusiasm I nearly forgot the rider: it's truly wonderful for piano players. Unfortunately for the manufacturers a large proportion of synthesizer players did NOT start off on the piano or quite simply have got used to, or prefer, the ultra-light plastic keyboards of the synthesizer era.

The other little problem that follows on from 'full length, weighted' etc is the cost of producing such keyboards. In fact it is fair to say that the cost, and therefore the price to Messrs Punter, is also 'full length' and very 'weighted'! Even worse it is a cost which forms a large part of the cost of every instrument fitted with that particular keyboard. This differs from the cost associated with the software that provides many of the control functions and assignability I will discuss later. Once the software has been developed then its development costs (which are admittedly high) will be spread across all of the keyboards sold that contain the software, effectively almost at zero cost to the manufacturer.

Imagine that it costs £40,000 to set up the production line and then £400 to build (components and manpower) each individual piano-feel keyboard. If you sell 1000 instruments then each one must include £440 for the keyboard ie. 1/1000th of the production set-up costs (£40) plus the cost of one keyboard. Since the electronics were going to be in there anyway, we can simplify matters: let's just say that the software development cost was also £40,000 and that the cost of putting it into each instrument is £4 (the cost of an EPROM plus the cost of blowing the software into it). The cost contributed to each of the 1000 instruments is now £44, consisting of a £40 share of the development costs and just £4 per instrument.

Full-length keyboards also provide further problems. They are wider than the three, four or (occasionally) five octave keyboards found on most synthesizers, so the case needs to be something like Andrex toilet paper: long and very, very strong - strong enough to avoid bending! Length and strength equals cost - plus a hernia everytime you move it, plus it won't fit on the backseat of the Mini! Gigging musicians avoid this sort of hassle for exactly the same reasons that they don't transport grand pianos - unless they're in the Genesis/articulated lorry/multi-roadie class that is.

Having established the problems, there are still good reasons why people will opt for such a keyboard. If it is to be permanently housed in a studio/bedroom then the size and weight problems fade away. If you are a piano player then the weighted keyboard is a must. The length of the keyboard is also required for quite a lot of classical repertoire as well as for some vicious pieces that Tony Banks can play that I can't... Also, when you split the keyboard on a KX88 you can have a generous, say, 3½ octaves on one side and 4 octaves on the other - both spans larger than some synthesizers' whole keyboards!


If the Master Keyboard is to be the cockpit of your MIDI network it's going to need a whole host of controls: buttons, toggle switches, sliders, wheels, footswitches, aftertouch, breath control, heartbeat, laser-based eye movement detector,... whoops, got carried away again! In fact the KX88 has everything in the list up to and including a breath controller. Some of these controls are used, believe it or not, to actually control the KX88! Most of them can be assigned to other duties as we shall see.

KX88 assignable controls (showing their 'default' assignments).

This is where the Master Keyboard starts to pay for itself a little. Instead of having to buy one foot pedal to control the filter sweep on synth A, another for the volume on synth B and a third one for dynamically controlling the aftertouch extent on synth C, plus a bevy of footswitches for portamento on this one and sustain on that one - why not just buy a minimum of such controllers (how many feet have you got?) and plug them all into the Master Keyboard, which will then route them to wherever they need to go?

This routing can be done on the fly by setting up a memory for each routing (the KX88 has 16 such memories) so that you can change from one set-up to another at the press of a single button. For example, if in the middle eight section of a song, you want to use your sustain pedal to trigger a sampler instead, just set up two memories (say numbers 1 and 2 for sustain and sampler respectively) which are identical apart from the assignment of the specified pedal switch. At the start of the song select memory 1. As the middle eight arrives select memory 2 and then reselect memory 1 at the end of the middle eight. If you want the pedal to cause both sustain and sample triggering, you can do that too!

In total, the KX88 can handle two foot pedals, two footswitches and a breath controller, as external controllers, plus all the inbuilt controllers including the obvious pitch-bend and modulation wheels, and the less obvious sliders (4 of), momentary switches (5 of) - which send one message when pressed, and toggle switches (2 of) - which alternately send one message when pressed and another message when pressed again.


So what exactly are all these controllers doing? Sending out MIDI messages that's what! When a synthesizer has built in to it both a volume control (a slider maybe) and the amplifier to be controlled, it's not difficult to imagine the one connected to the other by a piece of wire. Once the controller and the controllee are physically separate, somebody has to organise the communication mechanism and, as we already know, MIDI is it!

As anybody who has seen two synthesizers connected by one MIDI cable (master MIDI Out to slave MIDI In) will know, playing on one synthesizer's keyboard can result in the other synthesizer 'playing' the same notes. This is the first and most basic function our Master Keyboard must provide. If we arrange for other information to be both transmitted and received (and you may have to set this up in both the master and the slave instrument), then we can remotely control pitch-bend and modulation, for example. In fact, these two are fairly obvious because they both have defined MIDI messages which will be 'known about' by both master and slave.

Sometimes we may want to control pitch-bend in the slave instrument via a foot pedal because both hands are fully occupied. This is where the idea of assignment comes in. In a previous article where we looked at the Yamaha MEP4 (July 86), we saw how this device could alter parts of the MIDI messages received before transmitting them on. The KX88 can perform a not dissimilar function by changing the type of the MIDI message sent out by a given controller, to be that for any MIDI controller. In this case the KX88 would be instructed to assign the foot pedal controller movement to sending out the pitch-bend MIDI message.

Another useful trick the KX88 can perform is the merging of an incoming MIDI data stream with its own MIDI output. It is possible therefore to have more than one 'master' controller active at the same time. You could have a sequencer playing parts of a multi-timbral synthesizer whilst you play other parts live on the KX88 for example.


The final ingredient required by our Master Keyboard is the ability to cope with more than the obvious MIDI messages; anything that has its own message type - such as key on/off, pitch-bend, aftertouch, etc - ought to be dealt with as a matter of course. The assignability discussed in the last section should be provided quite generally so that you have the flexibility to control your MIDI network in any way you find useful. The icing on the cake comes when you can play with any of the parameters in the voice patch data inside your slave synthesizers directly from the controls already mentioned.

The KX88 lets you do this for Yamaha gear quite comprehensively, by inserting control values obtained from your dynamic movement of a control slider, foot pedal or whatever, into the relevant System Exclusive message. Since the System Exclusive messages sent out include the Yamaha Identity number, other makes of synthesizer will ignore them. To cope with this problem it is possible to programme two parameter changes (compared to the 64 'Yamaha only' ones) with 8 byte messages of your choosing. The 8 bytes can be anything at all which should allow you to make up a message that your synthesizer can understand, since a controller value can be 'connected in' to any byte in the message. Any of the 66 programmable messages can be assigned to any of the controllers and limits can be placed on the controller message bytes so that you don't send a slave haywire by sending illegal messages.

If you have a drum machine that can take its timing from MIDI, then you can control it very easily from the KX88; page 15 of the manual shows you how to set up one switch for 'Start', one for 'Stop', and a slider for tempo control.

It's also possible to select from the KX88 any of the 128 voice program memories (on slaves) that MIDI allows for. The KX88 will also let you dump up to 20 bytes of your own choosing but you have to feed them in by hand!


Once we've cottoned on to the fact that we have a microprocessor manipulating MIDI, it's not difficult to see how split and overlaid keyboards work. The KX88 is not as complex in this department as some other MIDI processors such as the MEP4, the Hinton Instruments MIDIC or the Akai ME25S. You have two 'Banks', in Yamaha terminology, which can transmit on separate MIDI channels. In 'Dual' mode anything you play goes out on both channels and therefore the two expander instruments you have connected will 'play' the same notes. In 'Single' mode only one of the two Banks is active so you can easily select which expander will play. Finally, in 'Split' mode the left and right ends of the keyboard each correspond to one of the Banks and the split point is selected by pressing a key. If you like, you can swap the Banks, transpose them independently, and select voice programs (on the slaves) also independently.


Dedicated Master Keyboards are still on sale from quite a few manufacturers, so somebody must be buying them! Apart from the KX88 from Yamaha, there is the new MX73 from Akai, the MKB200 from Roland and quite probably several others that I'm not aware of. Numerous electronic pianos such as the RD1000 from Roland and the PF70/PF80 from Yamaha are also available which are intended to provide Master Keyboard functionality on top of a good sound. These dual role instruments are designed to solve the price/performance problem discussed earlier of course.

Another route into the Master Keyboard scenario is to combine the talents of your current keyboard (assuming it doesn't have the necessary facilities itself) with a host of MIDI processing 'black boxes' such as the MEP4, the ME25S and ME30P (MIDI patchbay), the MIDIC. Or perhaps a MIDI-equipped microprocessor system might do the trick!

As a final comment, I should point out that the KX88 has tended to get somewhat buried in the general discussion of Master Keyboards in this article; it was used as an example rather than as the centre of attention it would have been in a review. My personal specification included a quality, full-length, weighted keyboard, lots of MIDI controllers available from one central MIDI source to feed into my computers, and the weight and length problems didn't raise their ugly heads.

The KX88? - I love it!

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Sound On Sound - Copyright: SOS Publications Ltd.
The contents of this magazine are re-published here with the kind permission of SOS Publications Ltd.


Sound On Sound - Oct 1986

Donated by: Gavin Livingstone



Gear in this article:

Keyboard - MIDI/Master > Yamaha > KX88

Feature by Jay Chapman

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