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Alesis MPX

MIDI Patch Transmitter

This latest add-on for the popular MIDIVERB and MIDIFEX lets you control the effect patch selection remotely by hand. Tony Hastings wishes he had thought of the idea first.

Tony Hastings tries out this addon remote control unit for the popular MIDIVERB and MIDIFEX.

About three years ago I was sat in a cafe doodling on a napkin when I suddenly had a brainwave. With MIDI about to become the greatest invention since the teasmaid, I reckoned what the world would need soon would be a remote control patch changer so that you could activate changes without using your main MIDI keyboard. Thirty napkins later I had the perfect design, the only problem was I didn't have a clue how to make it! So, like Leonardo and many others before me, I put the napkins containing my detailed designs aside for posterity and ordered another egg sandwich instead...

Three years on and guess what I've got on my desk in front of me? None other than a remote MIDI patch changer not a million miles away in design from my own idea but conveniently smaller and ready to use and with all the hard work done by someone with more suss than me. The MPX, as the gadget in question is known, has been designed by those awfully nice Alesis people who had the decency to bring us the MIDIVERB earlier this year which turned the world of digital reverb on its head.


The MIDIVERB was made possible by the adventurous use of Alesis' own custom RISC chip. That stands for Reduced Instruction Set Computer and is a bit like a preset computer only able to perform certain specific software functions. The advantage of using it is that it can perform those dedicated functions extremely quickly (about three million instructions per second) and can produce complex reverb simulations digitally that were hitherto obtainable only from units costing three or four times as much.

Messing about with chips obviously gave these Californians ideas, for hot on the heels of the MIDIVERB came the Alesis MIDIFEX, offering 63 completely different complex stereo effects that would normally require at least three separate audio processors to achieve in the studio.

However, the arguably 'big' compromise that both these devices make is in accessibility. First of all, the effects themselves are preset - so you can't tinker around with them as on programmable units. Secondly, to change effect patches on the units requires you to manually hold down an increment/decrement button until you've stepped through to the desired patch number. The only means available to go straight to a desired effect patch is to send a 'patch change' message (a MIDI Program Change command) to the Alesis unit's MIDI input from a MIDI keyboard (via a MIDI cable). In some instances that is both impractical and undesirable, so Mr Alesis has come up with the MPX patch changer principally for remotely controlling MIDIVERB and MIDIFEX units, but equally of interest to anyone with MIDI equipment.

The device itself is roughly the size of a box of kitchen matches but slightly shallower and a little heavier. It is battery operated (using four penlight batteries) and has one MIDI Out socket to connect with whichever device you wish to remotely control. The front panel comprises a 12 button keypad that includes two buttons marked CHAN and CLR.

At the heart of the MPX isa microcomputer that remembers everything you do and will recall the last setting for as long as there are batteries in the unit. It's clever enough to know when it's not being used too and, like some calculators, 'goes to sleep' automatically when inactive so as to conserve battery life. The MPX handbook, incidentally, claims that the average battery lifespan should be about two years, so you don't need to take out a mortgage with Duracell just to run the thing!


The first thing to do is decide which MIDI channel you want to send your patch changes on, because the MPX is able to send on any or all of the 16 available MIDI channels. To select a single channel you press the CHAN button once followed by your chosen channel number, 04 for instance. If you want to send on all channels simultaneously (as in Omni Mode), then you simply press CHAN followed by 00.

After setting the MIDI send channel you are now ready to send (transmit) a patch change command to your connected MIDI device (eg. MIDIVERB). There are two options available: Mode 1 and Mode 2, but before proceeding further you should press CLR to clear any data that may or may not already be in the MPX.

To change a patch in Mode 1 you simply press two buttons one after the other to indicate the patch number that you wish to call up. With a MIDIVERB connected you can only send a patch number between 01 and 63, any number outside of that range will be read as a mute command by the MIDIVERB. Up to 100 different patch numbers can be sent from the MPX, so obviously connecting a device with more than 63 memories will allow you to use higher numbers than with the MIDIVERB.

Mode 2 allows the user to set up a patch ready for change using only one button. You select the initial digit for the patch change (remembering that patches 1-9 should be prefixed with 0) and keep the button pressed down for more than 0.6 of a second. The MPX then waits for your second digit to be input, at which point it will send the selected patch change. This is a particularly good facility for live performance situations where you can be ready to change an effect quickly with one swift keystroke.


The Alesis MPX is a very simple and straightforward device to operate. Being battery powered and with 'intelligent' life-extending software it is convenient for both live and studio use. It looks like a big remote control for a TV but is ergonomically more pleasing, so no complaints on that front. In fact, I have no complaints at all. The MPX is one of those tantalising things you don't think you need until you use one, then you forget how you ever managed without one. What greater accolade can I give it except to say that I had to buy it?

Price £97.00 inc VAT.

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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 - Dec 1986

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MIDI Utility > Alesis > MPX

Review by Tony Hastings

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