Lots to discuss this month, the computer music market having shown a bit of a spurt recently. In short, packages are getting cheaper, better, and easier, all at once, no strings attached.

In fact there is one string attached, if you own a BBC Micro for instance. The one string is that all the good stuff is coming out for the Commodore 64, which is still about in its millions, remains comparable with the new C128, and can now be bought for some shiny beads and a mirror at all good high street witch doctor's.

For instance, Commodore's 'Sound Expander' FM Sound Module turns the 64 into a music computer increasingly similar to the Yamaha CX-5. The sound chip in the Expander is manufactured by Yamaha and offers eight-note polyphonic playing of DX-9 type sounds.

The basic layout of the software, whether on disk or tape (either package is £99.95) is a bit 'Play-Along' oriented, with control either from the computer (with a Music Maker clip-on keyboard if you're wise) or from an upcoming full-size mechanical keyboard connecting to the Expander's left-hand multipin slot. Routines for communicating with MIDI are already in the software, and a MIDI interface fitting into the top cartridge slot will become available soon.

Basic playing options include normal or single finger chords, octave transpose (vital if you're using the short Music Maker keyboard), Ensemble On/Off for richer sounds limited to four-note polyphonic playing, Chord Memory, Programmable Split point, variable Border Colour and so on. Splitting the keyboard allows you to play two sounds at once — perhaps a bass synth with the left hand and piano with the right — and there's a good selection both of imitative and of abstract synth sounds.

Decent sound programming software is on its way, but at the moment it's only possible to adjust the overall brightness of a sound. In addition to the poly sounds there are 12 preset rhythm accompaniments, each having its own arrangement of bass and arpeggio patterns, with reasonably lifelike percussion sounds. The 'Riff Machine' section produces complex backing with percussion and accompaniment sounds in various styles — Country, Pop, Disco and so on — and these can be chained together to form an endless (if mindless) backing track.

Also forthcoming is an FM Composer software package which will allow you to create lengthy six-voice pieces; the sound output of the Expander can be sent either to the TV monitor or to a hifi or other amp or a mixer, so although you won't have separate outputs you should be able to record the system very effectively.

The various menus of the Expander software pull down in a very simple manner and are colourful and easy to use. The package comes with a set of chord stickers for the computer keyboard and a simple song book with a chord chart; the main display flashes up all the notes you play on a music stave, so the package is pretty educational for non-keyboard players.

Less educational but even more fun is the Commodore Sound Sampler (£69.95 disk or tape), built into a similar module with two added controls for Feedback and Output Volume. A small microphone provided allows you to sample sounds monophonically and you can control pitch from the computer or music keyboard. Musical dogs, cars starting, rude noises and even Orch 5 (it's Fairlight time) can all be yours, although the demo sounds provided concentrate on conventional drums and Latin percussion.

The maximum sample length is 1.6 seconds at what sounds like 8kHz response, which is basic but usable, while the Quattro Sampling mode allows you to take four shorter samples and sequence them in 16-beat patterns. Any sampled sound can be displayed as a waveform and neatly edited using the cursor keys, and it's also possible to transpose sounds over 19 octaves.

Loops can be defined to repeat either the whole of a sample, or just a short portion of it to give sustain if desired.

And there's more! The Sampler also acts as an Echo unit with a maximum delay of 1.6 seconds and the number of repeats is set by the Feedback control on the module. It also acts as a Pitch Convertor (harmoniser) which can raise or lower the pitch of your voice or any other sound by up to one octave, with other musically useful intervals such as fifths and thirds also available. This section of the software is handy for thickening vocals or for silly special effects — for instance if you want Pinky and Perky to take a guest spot on your next single here they are!

The Sound Sampler is enormous fun and just about of high enough quality for semi-pro recording purposes.

If you do have a C64 but don't want to spend even as much as £69.95, the Commodore Sound Studio could be for you. At £14.99 (tape or disk) it uses the 64's built-in three voice sounds synth chip, the SID chip, to synthesise sounds and record tunes.

Again you can use the Music Maker keyboard; 60 preset sounds are available and there are two main pages for synthesising your own sounds. Page A allows you to set Waveshape, Pulse Width Modulation and Depth, Attack, Decay, Sustain and Release, Vibrato and Portamento Depth, Filter, and Oscillator Sync (for metallic effects). Page B allows you to set the filter Cutoff point, ADSR, Resonance, LFO sweep and Master Volume. You can control all this with a joystick and new sounds can be saved to disk.

The Sound Editor section can be used to record melodies in real time or step time one voice at a time. Realtime pieces can be edited (just a list of note times is displayed, nothing as complex as a musical stave) and three additional voices can be controlled if you use a MIDI interface to a synthesiser. This provides a nice way of stepping up if the package really gets hold of you; the Commodore MIDI Interface will be around the £49.95 mark and of course MIDI synths nowadays start at around £290.

In the Sound Editor section various time signatures including 3/4, 4/4, 5/4 and 6/4 can be recorded, tracks can be deleted and transposed, and completed tracks can be saved to disk. The handbook includes two rather complicated pieces of music for you to struggle with (House Of The Rising Sun and a piece of Paganini — who chooses these things?) and some helpful basics on the physics of sound and synth design.

Now to go a little upmarket with Steinberg's Pro 16 compositional package (around £90) and MIDI interface (around £135).

The German Steinberg gear (now imported by the Oxford Synthesizer Company and available through various dealers including London's Rod Argent's and Chromatix) is touted as being fully professional software for composition and sound editing. But it's very easy to use, the Pro 16 for instance being laid out almost entirely on one screen.

Sixteen polyphonic tracks of music can be recorded in step time or in real time with a metronome, the maximum length of one section being 64 bars of any time signature. Normally you'd assign each channel to transmit on the MIDI channel of the same number, so that Channel 1 would control a synth set to MIDI channel 1, Channel 16 would control a synth (or expander or drum machine or digital delay) set to channel 16, and so on.

You can chain 256 patterns together to form a Song which can be stored to disk. The interface allows you to sync to a MIDI drum machine or to tape (a smaller and cheaper interface has these functions as an optional extra).

One unusual aspect of the package is that many parameters such as tempo and MIDI channel can be changed while the music is playing. Moving vertical bars indicate activity on each channel and the presence of Velocity information, and other readouts show bar and beat number, memory remaining and so on. Total capacity is 8000 notes and most of the functions depend only on the Cursor, Function and Shift keys.

Down the right of the display is a vertical bar which shows 25 out of the 256 patterns which can be chained into a Song. You can scan up and down the chain using the computer's function keys and simply type in whichever patterns you want to occur in whatever position. The tempo and time signature of each pattern remain completely independent so you can have all sorts of tempo changes within a song.

The Pro 16's capacity is pretty amazing. You can write 64 patterns of up to 64 measures of any time signature, chain 256 patterns into a song, quantise to 96th notes to correct your playing, and freely combine step time and real time note entry. Using the step time entry is a little weird, as you hear any realtime tracks already recorded lurching along in time with it, but it's possible to Mute any tracks you don't want to listen to. In fact, the whole package is laid out in imitation of an unusually flexible 16-track tape recorder.

Each channel number active at any given time is blocked in green, and inactive channels are white. Underneath each channel is its MIDI transmission channel number. The lower half of the display shows Tempo, Bar No, Time Signature (in two parts, of course), Quantisation, Record status, Song or Sequence mode, Step Number per bar, Memory, Velocity and Disk functions.

There is a simple second page which allows you to time-shift tracks to compensate for any MIDI delays, but it's not likely that you'll need this. You can, however, use the page to create long delays or short chorus-like effects using two synths playing the same sound.

In terms of MIDI performance, the Pro 16 copes happily with velocity, pitch bend, patch, after touch and breath control information, although you can filter out (for instance) velocity information to save space in the 8000 note memory. But despite all its versatility the Pro 16 is very easy to get to know, and packed with useful features. For instance, if you simply press the 'A' key on the computer, every single connected synth sounds an 'A' for tuning up!

Given the present low price of a C64 and disk drive, the Steinberg must give the Roland MC500, the Korg SQD-1 and even the LinnSequencer a run for their money, although like all computer packages it's a dodgy prospect for live use.

And like all computer packages, the Steinberg has the advantage of adaptability. Once the interface has finished being a sequencer you can persuade it to act as a Casio CZ synth editor, a DX7/TX7 editor, a Mirage editor, and a comprehensive Score Writer for existing Pro 16 sequence files. But we'll look at those packages another time.

Enquiries: OSC, (Contact Details)