Over the past three or four years musicians have been endeavouring to persuade certain types of electronic instruments to work in a way for which they weren't actually designed. It wasn't until the advent of MIDI that different makes of drum machine and synthesizers were able to converse with one another. Prior to this, drummers wanted to do unmentionable things like extracting the sounds from a Linndrum via a Simmons-type pad in real time. This they felt, quite rightly, would allow them to influence the machine and allow the drum part to breathe. (All this without the necessity of using drums or microphones. It also meant they didn't need to spend valuable studio time getting a halfway decent drum sound.) Other chaps wanted to be able to link their drum machine to a Simmons brain to modernise the sounds, and even more wished to change the sounds they'd already recorded onto magnetic tape. (This particular dream was never easy to realise and one invariably ended up with slightly delayed off-beats and the like. These had to be tightened up by turning the tape over and re-recording the offending track with a digital delay.)

Yet another ostensibly simple operation which was difficult to achieve was to trigger a Simmons brain from your acoustic drum set via a microphone. However, all or most of these problems are about to become a thing of the past. Syco have come up with an ingenious little rack-mounted unit called PSP which is designed to accomplish all those things, and more.

PSP stands for Percussion Signal Processor, which not only allows pad to MIDI and MIDI to trigger conversions, but also has 'path' facilities which enable you to work on a signal from the pad before it gets to the actual sound generating electronics of the instrument(s) it's connected to. (These changes, or patches, are memorised by PSP). To accomplish this the unit's computer needs to glean information directly from the Piezo transducer which is inside the pad. Obviously velocity is important because of 'touch-sensitivity', but other factors need to be incorporated too.

The unit has the facility to accept eight drum pads as well as a hi-hat switch. Each pad has what Syco call its own set of performance parametrics which can controlled by a single Rafi button (like Neve use for their mixers) which may be assigned to any pad. These parameters are clearly marked and directly linked to a seven segment display. Thus, if we decide to work on patches, we have 99 different options for sound settings. In this case, a patch may be construed to be a 'kit' in Simmons parlance. Programme is actually for MIDI programme change from 0 to 128. (Bank two comes in after 64 and shows a dot to let you know it). Note is pitch change and encompasses 10 octaves. The window will display the note with a dot for each semitone and a number for each octave. This pitch info can show in the window every time you hit a pad and an LED lights upon the relevant button to let you know it's triggering properly. Duration lets us adjust the length of each note from 0 to 9.9 seconds and Syco thoughtfully provide a footpedal to 'kill' the note should you so desire. Bend does what you'd expect but so far only in a downwards direction. It, too, can be almost 10 seconds in duration but won't actually descend for that long. This is a dynamic function and the pitch lifts a little as you strike the pad. The next button controls Feel and gives us 12 factory-set options. The first is linear like Simmons, the next is exponential and rises faster at first, the third has exaggerated dynamics while the fourth has uncontrollable random dynamics. This one is evidently useful should you decide to keep your 'click track' since it accepts random beats. All the other numbers have their very own effects and the very last one gives you a soft response when you hit hard, and vice versa (I haven't been able to think up a use for this particular condition but if you come up with one don't hesitate to let me know. Send your answers on a postcard to: Horace Batchelor, Keynsham, that's K,E,Y,N... ) The very next button is Channel and allows you to assign pads to any one of 16 different positions so will link to as many different keyboards as you can afford. One simply raps the pad sharply and the keyboard it's joined to will sound. That's the magic of MIDI.

Now, all those aforementioned numerical changes are brought about by a rotary knob called an incrementor. Simmons, too, have this facility on SDS7 but PSP's is superior. It's used on Quantec equipment and has very fine click stops built into it. (We can also put the unit into safe so that it won't wander from patch to patch as we play.) Further to the right are another pair of buttons. The first is store and memorises information; the second is function which works in conjunction with the pad buttons to accomplish different things, eg it will transmit all patch data in MIDI to dump to a sequencer or disc in double quick time. Press button six and we can adjust the mating of different pads to PSP. Button seven adjusts the width of the pulse to cut out (or set up) false triggering. This feature might prove useful for adjusting arpeggiators or the like.

That, my friends, just about sums up the front of PSP so I suggest we move swiftly to the rear.

The back has two horizontal rows of XLR sockets — these take the trigger inputs and outputs. All the 'ins' have a small sensitivity trimmer 'pot' which you adjust with a small screwdriver, but there's also a threshold control to cut out interference. The company fit a Europlug-type mains lead whose female holder is fitted with a fuse. To change the voltage one simply turns the fuse holder over and replaces it. I mentioned the 'kill' switch before and there's also another footswitch which enables us to change patches. The only other things at the back are the trio of MIDI sockets. One is for input and the others for output. Output two will only send really vital patch information along the line since it will all be passed back anyway: this saves sequencer memory. However, if you really must send all the info then simply plug into output one. (To draw an analogy it's better to send information from claves rather than much more complicated data of (say) a cymbal.

If we are programming PSP and make a 'fatal crash' we need only to hold in Store and function whilst powering-up for the machine to switch to its default settings. If we press Store while switching on the machine will reset and retain what was in the memory.

PSP evolved from an early analogue to MIDI interface which was aimed to fill a gap which Syco had spotted in the market. People were asking them how they could drive Simmons from Fairlight or DX7s from external pads and Syco decided they could oblige them by adapting a piece of equipment which they already made. I'm not sure whether PSP is meant for drummers who wanted to get into keyboards or vice versa, but either way it's valid and an extremely useful piece of equipment.

Because of the philosophy behind it isn't particularly cheap; it's aimed at people who at the very least own an SDS7. It may not be necessary to use the unit with these new, hush, hush Simmons when they arrive since I suspect they'll already have MIDI built into them. However, it will still work admirably for many other applications. After all, what could be better than being able to mix notes from a DX7 with drum sounds from Simmons or Linn?

SYCOLOGIC PERCUSSION SIGNAL PROCESSOR - RRP: £776.25