Acorn Computers are fortunate to have a software house producing programs specifically for their machines. One of Acornsoft's latest products is of particular interest to music makers, the so-called Synthesiser tape. The Atom computer has a small loudspeaker built-in, so once you've loaded the program from cassette — a process that takes about seven minutes — no more equipment is needed to start producing tunes. If you prefer, the Atom's audio output is available on a socket on the back and could be fed to an external amplifier, and to other sound processing devices if available.

The first section of the cassette is the INDEX file, which lists the tape's contents and contains a test sequence consisting of the computer's character set repeated both normally and in inverse video. Even if you've been successfully recording and playing back your own programs, Acornsoft's level may not be the same as yours; the test sequence enables you to set your playback volume accurately. My little portable recorder proved to be woefully inadequate for the task of playing back the Acorn's CUTS encoded tape, and I eventually used the Tascam 124 (reviewed last month) with every success, and 100% reliability. It shouldn't be necessary to go to such elaborate lengths, however; I only used the Tascam because it was handy.

The bulk of the tape is the SYNTH program itself. When run, it displays the prompt: M/R/P/E/S/L/T. Entering one of these letters will make the program do your bidding, any other characters it just ignores. M is for manual, and in this mode the ASDF... line of keys becomes a 1½ octave keyboard (from B to F — a strange choice) with some of the QWER... row being used as accidentals (black notes) where appropriate. As you're playing, a row of staves display the notes as black blobs, or hollow blobs for sharps.

Different note lengths aren't differentiated, because there is only one length; if you hold a key down, the note and blobs repeat rapidly like musical machine-gun fire. In other words, the musical notation that appears on the screen is a bit unorthodox, and it's a pity that more conventional note symbols aren't used in view of the Atom's high-resolution graphics capability.

You can only play one note at a time, and there is a choice of four different 'instruments' which can be selected by typing a number from 1 to 4; and you can change instruments as you're playing. The Atom's loudspeaker is driven by one bit of an output port; in other words, the sounds are made solely with rectangular waves without filtering or envelope shaping, and it would be churlish to complain about the instruments' sounds. Waveform 1 is called harpsichord (it sounds more like a clarinet), 2 is electronic synthesiser, 3 is bass guitar and number 4 is Hammond organ; Hammond ought to sue for libel! None of the instruments is particularly realistic, except for number 2 which has no reality to relate to, but number 4 sounds like a steam calliope with a collapsed lung!

By typing R, a tune can be recorded as you play it again with waveform changes if any. There are four locations available to store tunes in, each one 255 notes long, specified by letters A to D. Wrong notes may be deleted easily, and rests can be inserted using the space bar. If you can play, and it's difficult on the typewriter keyboard, the tune can be entered in real time; if you can't play, it's equally easy to enter a piece "blob by blob".

Once the tune is entered, it can be edited by typing E. A cursor can be moved back and forth above the music, and notes may be inserted, deleted or changed with ease.

The music can now be played. There are seven tempos to choose from, with a reasonable range, specified by typing T followed by a number from 1 to 7. The letter P can then be followed by letters A to D and numbers 1 to 4 in any combination. This string is read from left to right; a letter causes the corresponding tune to play, whilst a number changes the waveform if you haven't actually specified this within the tune itself. So for example, P2AA3C causes tune A to play twice, using waveform 2, followed by tune C played with waveform 3. Quite long strings can be set up this way, with the limitation of only four tunes to choose from of course, and tempo cannot be changed in the middle of a string. The longest tune that can be set up without repetition is 1020 notes, which should be long enough for most users.

Finally, each tune of up to 255 notes may be saved as a file on cassette, and reloaded as required, using commands S and L. Three demonstration pieces are provided on the cassette to get you started.

The name Synthesiser is a bit of a misnomer when applied to this program, since you can't get at the sounds and mess about with them to create your own; perhaps Music Box would be a better title. It's good fun for all ages though, and it must be better than continually blasting alien life forms from the screen.

The Atom Synthesiser cassette costs £11.50 including VAT and postage from Acornsoft, who can be found at (Contact Details). You will need 5K of program memory and 6K of graphics memory to be able to run the program.