'Rhythm Activation Program' is the name given to the latest onslaught of British software genius. The company is MIDIsoft, the software is a must for MIDI drum machine users.

Way back in the history of MIDI, someone, somewhere had the bright idea of associating drum voices with MIDI pitch numbers. The idea was a pretty neat one, because it gave musicians the ability to play a synthesiser from a drum machine, and vice versa.

It's great fun, tapping melodies into a drum machine or using touch-sensitive keyboards to play percussion voices with dynamics. But this interaction also raises the possibility of recording rhythm patterns into a non-dedicated MIDI sequencer, either from a drum machine or from a synth.

Now, some drum machines have fixed pitch-to-voice correlations, whilst others allow you to define your own. Either way, there's certainly no standard configuration, so a sequencer which allowed you to build up a library of such configurations which could then be imposed on any rhythmic sequence would obviously be very valuable - your drum patterns would be available for use with any MIDI drum machine.

Hey presto. British ingenuity comes to the fore once again in the shape of a software package called RAP (for Rhythm Activation Program). It's available for 48K Spectrum and Commodore 64, and can best be described as a centralised rhythm programmer that employs the same sort of matrix display as Roland's recent drum machines and Yamaha's RX editing software.

RAP allows 200 patterns to be created in step time from the computer's QWERTY keyboard — though sadly, you can't input anything over MIDI. The patterns are organised in two banks, and can be chained together in 16 independent tracks. Each pattern can be up to 16 steps/beats long, and use up to 16 voices playing concurrently. Each voice has its own MIDI channel number, MIDI pitch number and a maximum ten-character name.

The ability to assign a different MIDI channel to each line/voice of the matrix opens up the possibility of playing patterns on a hybrid system using more than one drum machine. It's equally feasible to incorporate synths and samplers into a rhythm pattern by virtue of the fact that it's MIDI pitch numbers that are being sent from RAP over MIDI — though as soon as you start thinking about pitches, you're faced with the headache of having to convert familiar pitch letters into MIDI pitch numbers.

Not being one to shirk from the reviewer's lot, I dug out TR707, RX15, RX21, DX7 and JX8P for a trial run under RAP's control, using both the Commodore and Spectrum versions.

And almost without exception, the program worked really well. The one problem to emerge was with the RX21, which made no more than rather sporadic attempts at responding to RAP's output. In all fairness, this might not be a problem with the RAP software itself. Whatever, MIDIsoft are now aware of the problem and are investigating further, so if you're an RX21 owner interested in RAP, get in touch with them before parting with the readies.

One point to bear in mind, though, is that a MIDI note-on period is limited to the duration of a single step. Thus, where synth sounds are concerned, the duration of a note depends on the sound's release phase. Another noteworthy point is that it's not possible to enter triplets via RAP's step-time method.

But the most significant omission, given RAP's ability to include synths in its rhythmic excursions, is a facility for storing patch changes between patterns in a track. Were such an option available, you could switch from a marimba to a koto, say, between different patterns or two renditions of the same pattern.

The Spectrum version of RAP allows you to choose between six different interfaces: XRI Micon, SIEL, EMR, JMS, E&MM's own, and an obscure device marketed by a now-extinct magazine based in London's docklands. The Commodore version caters for a more modest selection comprising just SIEL and JMS.

The program divides broadly into three areas: pattern creation and editing, track creation and editing, and a third set of functions carried out by a customising editor.

Moving around the system is very easy, thanks largely to the appearance of helpful on-screen prompts at almost every stage. There are also Help pages for the pattern and track sections, which give an on-screen list of all the commands available for the specific section.

"Facilities - Being able to assign different MIDI channels to voices lets you use a hybrid system of more than one drum machine."

Writing patterns, which entails step-time input from the computer keyboard, is a fairly straightforward affair. You're presented with the above-mentioned 16-by-16 matrix, round which you move a cursor with the help of the, er, cursor keys. A joystick would have been swifter, and a mouse quicker still. All the same, the 'global' approach adopted by RAP, whereby you have the whole pattern in view at a time and equal access to any part of it, is a welcome feature that makes programming patterns quite straightforward.

As you might have guessed from RAP's step-time nature, you can't input or edit a pattern while it's playing. However, you can start and stop playback at any point without affecting the stage your input's currently at, which minimises the transition time between input and playback.

Other facilities allow you to call up the adjacent lower and higher patterns, decrease and increase the tempo between 1 and 240 beats per minute (though not whilst a pattern is playing), set the last step in any pattern (from 1-16 steps, irrespective of how many steps you've actually entered), clear the currently-positioned line, clear the current pattern, copy the current pattern to any other position, and rotate the current pattern. This last facility rotates the whole pattern one position at a time to the right (the last beat becomes the first, the first beat becomes the second, and so on).

Dynamics handling is limited to an accent value (between 0 and 7) which can be specified for each step — but not each voice — in a pattern. Compared with the velocity resolution MIDI makes possible, this is obviously a bit limited.

In the case of an instrument such as Sequential's TOM, which assigns specific pitches to dynamic and tuning levels as well as to voices, RAP isn't going to be able to do the machine's capabilities anything like justice.

The track section allows you to chain patterns together to create up to 16 independent tracks, each of which may have up to 1000 links. Even allowing for the fact that there are no extra song construction facilities to reduce the number of links that need to be input, that upper limit is going to seem rather excessive unless you're writing a symphony. Maybe the program would benefit from having fewer links per track, and allowing several configurations to be resident in memory instead. What with the slow loading times that are part and parcel of using the Commodore disk drive, and the even slower ones inherent in cassette loading, this would be an especially useful feature.

Once you've selected the track you want to input or edit, you're presented with a screen not unlike that for pattern input, only here the pattern you choose for the current link is presented only for information purposes. Other information presented on-screen includes the current link number, the number of links in the track, and the status of Insert mode.

Facilities available (all accessed by single or, at most, double keypresses) allow you to auto-repeat through all 200 pattern numbers when selecting a pattern for each link, autorepeat forwards and backwards through the links, go to the start or end of a track (but not straight to any link), erase an individual link or a complete track and toggle the Insert function on and off. With Insert off, entering a pattern automatically overwrites the currently-assigned pattern. With it on, the currently-assigned pattern is moved along one link to make way for the new pattern. Usefully, you can also fast-forward or rewind through a track while it's playing.

Problems? Well, because MIDIsoft have opted for an on-screen pattern display complete with customised information, there's no room left for a listing of the patterns used in a track. Unfortunate, but it doesn't detract from what is in all other respects an excellent display, and very accessible piece of software.

Unlike the pattern section, this one forces you to return to the menu and select a 'play track' option. But once you've made that selection, the option allows you to set both playback speed and the number of repeats. You can have between one and eight of the latter, which seems a bit stingy. An infinite repeat option would have been useful, too.

When it comes to loading and saving data, RAP offers a fairly flexible set of options. You can save pattern banks individually or together (but not individual patterns, unfortunately), tracks 1-16 as a group or individually, customised configurations, and all performance data. And the good news for Spectrum microdrive owners is that the Spectrum version can be converted to run with microdrives rather than cassettes.

"In Use - The advent of RAP means you could hire a drum machine for a day without worrying about programming intricacies."

RAP fulfils what is essentially an ancilliary function, and is most likely to be used in conjunction with a general-purpose sequencer. Fortunately, MIDIsoft have had the good sense to include an internal/external MIDI syncing capability. The system obviously benefits from the ability to function within a larger sequencing environment, or even a SMPTE-controlled one.

One annoying limitation — and this is where the eight-bit computers' limitations show up — is that if you select external clock, you lose the pattern display. The reason, in the case of both versions, is that the computer must constantly monitor for incoming MIDI timing bytes, with the result that there's no processing time for updating the pattern display.

But RAP epitomises the strengths of software devised for non-dedicated micros. It allows a central program to control any number of MIDI drum machines, gives users of all MIDI drum machines the sort of visual feedback previously only available to a few, and offers a very easy method of step-time recording.

Obviously, there's also tremendous value in having a central pool of rhythm patterns and sequences, which you can play on any MIDI drum machines with the appropriate customised pitch-to-voice configurations. Apart from the more obvious benefits, the advent of RAP means you could hire a drum machine for a day without having to worry about learning its programming intricacies — all you'd have to know would be the pitch-to-voice correlations, which could then be included in your customised library.

Even if you have only one drum machine, RAP still offers the attraction of a useful visual step-time entry system, and extensive pattern and song storage capacity - with the important added attraction that all your patterns and songs are instantly available should you buy another, more facility-laden drum machine at a later stage.

And RAP also provides a useful — though limited — method of incorporating synth voices into rhythmic patterns.

If all this sounds appealing and you take the plunge, you might find yourself having to buy a second computer on which to run RAP if you've already got a micro-based sequencer. This is where the ridiculously cheap Spectrum really scores — though it does mean you have to contend with the sluggish operation of tape or microdrive.

That sort of operational sloth will probably keep RAP — and a lot of other software written for cheap home micros — out of many professional environments like recording studios. Which is a shame, because a good deal of this software is actually more inventively written than that devised for more intelligent computers like the Apple Mac and IBM PC, or dedicated systems such as the Fairlight.

Expanding on the concepts RAP embraces in a package written for one of the above shouldn't prove too difficult, and the results could be staggering.

Until that happens, RAP performs several extremely useful functions, and performs them within a program that's for the most part clearly laid-out and easy to use. Its designers deserve credit for (a) having such a good idea in the first place, and (b) putting it into practice on limited, but affordable, home computers.

Price £37 including p&p

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