Out of the computer's disk drive crept hundreds of tiny green creatures covered in slime. The monitor sprang to life revealing pictures of hideous, contorted faces laughing and cackling. I felt the sweat pouring from my head, my hands were cold and sticky. Then I woke up and remembered the gig we were playing that night...

Sequencers; what would we do without them? Well, for those attempting to recreate on stage, songs which have been written in the studio, the answer would involve tape machines or employing an awful lot more musicians.

Modern sequencing programs incorporate facilities with the express purpose of keeping a 'live' feel to music recorded on a computer. For example, the resolution of current Atari ST sequencers is around four times that of earlier programs, so musical nuances are faithfully preserved. Consequently, computer sequencers are more than capable of recreating the live feel imparted to recorded music. The real problems start when we attempt to take this kind of sequencer on stage.

But is there any need? There are many standalone sequencers which are quite self-sufficient and therefore ideal for use on stage.

Not all are suitable. The cheaper ones tend to use a tape interface for the saving and loading of songs (rather than a disk drive) and invariably have insufficient memory to hold an entire set worth of material. The consequence of this is that songs have to be loaded midset using a slow and often unreliable means of data transfer. Though possible, no one would recommend it.

Some older sequencers have a built-in disk drive, but instead of standard floppies use Quick Disks. These are so named because they can load the entire side of a disk in a few seconds - the trade-off being that they hold very little data. From a live point of view, they have three main disadvantages: only one song can be saved per side, disks have to be physically turned over to access the second side, and they are quite expensive and difficult to get hold of.

Given that each Quick Disk can hold a maximum of two songs, you could end up with something like ten or twelve disks sitting on top of your keyboard - with all the attendant problems of making sure you select the right one and being equally certain it is inserted the right way up. For many, this is the stuff of nightmares when it comes to live performance.

By contrast, modern hardware sequencers are usually equipped with built-in 3.5" disk drives. And whilst still, perhaps, having insufficient capacity for an entire set, have the advantage of much faster loading times.

All of the above assumes that the sequencer used live is also the one being used to record the songs in the first place. But if it isn't and a computer-based sequencing program is the mainstay of the recording set-up, the problem of transferring song data from one system to another rears its ugly head - so how about using the original computer system live?

It's a simple fact of life that most computers are not designed for the rigours of live work. The first problem is one of internal protection; the action of being shaken about in the back of a car or van can easily lead to memory boards being dislodged or damage occurring to disk drive heads. Drop most computers once and you won't need to worry about problems with loading song disks - you'll be too busy trying to find a repair shop!

A second problem lies in a computer's susceptibility to radio frequency (RF) and electrical field interference. Place a monitor near power lines which are carrying pulses from a lighting box and the result is likely to be screen interference in the form of moving/shuddering lines which make it impossible to read numbers and letters. Thirdly, few computer sequencing programs are designed for live work and so the facilities necessary for use on stage are not usually implemented. These include the ability to have more than one song in memory and the facility to load one song while playing back another.

It is certainly possible to record songs on a hardware sequencer and to use that sequencer live; many of you probably do. However, the reduction in price of Atari, Amiga and PC clones (the latter running software under the Windows environment), has led to the majority of sequencer users opting for a computer-based program. Consequently, a possible solution to our problems is to use a computer-based sequencer for recording songs and a hardware sequencer or MIDI playback module for live work. Songs recorded on most computer sequencers can be saved in MIDI File format, a generic method of saving song data for reloading into another program even on a different computer. There is a possibility that the live sequencer may not be able to load MIDI File format song files, and if this is the case songs will have to be transferred by a MIDI Out to MIDI In link between the computer and live sequencer. Obviously this process can be fairly time-consuming, but once done, the files can be saved to the sequencer's own disk drive and then reloaded in the normal way.

As regards the sequencer itself, there are two types of device which can be used. The first are straightforward hardware sequencers, but problems like insufficient memory and delay in loading songs mentioned earlier are also true here. The second type are MIDI data playback modules or MIDI data filers as they are often known. A popular example is the Alesis Datadisk which can record MIDI data and play back directly from disk so preventing any substantial delays from occurring between songs.

As it is not actually designed for the purpose of playing live, it cannot playback MIDI Files and doesn't allow you to pause in the middle of a song. On the other hand, Datadisk is a 1U rackmount which has been built for mobility and so would be quite at home in a stage environment. It's broadly similar in design to the slightly cheaper Elka CR-99 and both can be used to store sounds and patches from synths on their built-in 3.5" disk drives.

The Roland MC series of sequencers now have the MRM software which enables them to read MIDI Files directly from a DOS-compatible disk - including Atari ST disks. This is an interesting alternative, but possibly a little expensive when one adds up the cost of the sequencer and MRM software. However, the MC series is robustly built and a favourite among professionals for live use (Go West used to use a pair of MC500 sequencers for the keyboard backing).

Yamaha's new battery-powered MDF2 is a perfect example of a multi-purpose device which will fit the live bill as it can play MIDI Files from DOS-compatible disks and does so directly from the disk, so preventing delays between songs. The only possible problem is that it can only handle format 0 MIDI Files which means that you have to mix down each song onto a single track on your sequencer before saving to disk. Roland's Sound Brush SB-55 could also be considered; like the MDF2 it will play any MIDI Files, again directly from disk.

Unfortunately, both units only have a single MIDI Out, so if your studio sequencer system is using a MIDI port expander, a degree of data re-jigging might be necessary.

There is one other possibility which is worth considering - a product which you will find on review elsewhere in this issue. Hands On MIDI Software have an Atari ST package called On Stage which allows you to use an ST live without the need for the monitor - in many ways the most vulnerable part of the system. The software lets you organise up to 32 songs into four banks of eight each and control their playback from a MIDI keyboard, while a small box plugs into the printer port and uses LEDs to allow you to monitor the current situation. It also has the advantage of supporting a custom MIDI port expander which gives you the availability of 32 MIDI channels. But don't listen to me - go read the review for yourself...