MIDI works. It is the most successful standard since they agreed on the space between railway lines. A result of this success is that the MIDI synthesizer module is now, after a shaky start, selling very well. In part, this is due to the player with an existing MIDI keyboard who wants to layer one sound with another but the majority are bought by the musician who only needs one keyboard to program his sequencer or computer which, in turn, then plays his keyboardless modules.

The trend will grow as computer software becomes more professional and as sequencers, like other CPU based devices, become better and cheaper. The recent launch of the MC-500 MicroComposer is sure to promote this growth.

Most synthesizers and modules, however, only make one type of sound at a time, regardless of how many notes can sound. This has meant that to play a composition featuring rhythm, bass, chords and melody the computer musician needed to own a rhythm unit and three synthesizers. Now, because the Roland MKS-7 Super Quartet is a multi-timbral sound module that can perform all of those functions at one time, this is no longer necessary.

Finished in ivory or rack-mounted black, the MKS-7 is specially designed to be played by a computer or sequencer. It has a PCM drum sound module and seven velocity sensitive Juno-106 voices which are divided into four separate sections to be accessed by four different MIDI channel numbers. This gives independent control of rhythm, monophonic bass, four note chords and duophonic melody and harmony.

The Super Quartet is essentially a preset instrument but that imposes few musical limits. The melody and chord sections have a choice of no less than 100 different sounds ranging from realistic traditional instruments to classic Juno patches. It even detunes the chords from the melody by two cents to give a more natural feel.

A comprehensive selection of 20 bass sounds, again makes it suitable for any style of music. These can all be selected by MIDI Patch Change information or by manually pressing the ten keypad buttons on the front panel.

Although it is a pre-set instrument it is possible to write a computer program to send MIDI exclusive messages to edit the MKS-7 to play the user's own sounds.

The rhythm block, (whose sounds are the same as in the TR-707 rhythm unit) consists of bass drum, snare and three toms, rim shot, hand-clap, open and closed hi-hat and crash and ride cymbals. It is the perfect instrument to use with the new MC-500 which has a special rhythm track to easily program drum parts. The MC-500 can then store up to eight complete songs internally, including the rhythm track, and others can be quickly loaded in from disk.

In the whole mode the chord and melody sections combine to give a six note polyphonic synthesizer that can be played from either sequencer or a keyboard. By using the split keyboard facility from a mother keyboard, like the MKB-200, the left hand can control the bass section whilst the right hand plays the melody and chord sections.

In Japan, something called karaoke is very popular. Karaoke means literally 'empty orchestra' and involves people, at home or in bars, singing popular songs to tape accompaniment. Taped backing is not very satisfactory, however, and accompaniment is now being programmed on a sequencer which provides backing with real live synthesizers. The MKS-7 has a transpose function in case the programme is in an awkward key for the singer. It is unlikely to become popular in this country, of course, but the transpose function could be useful when it is being played from a keyboard and the singer prefers another key to the one that is written.

A choice of outputs makes the MKS-7 Super Quartet suitable for a variety of applications.

One master output sends all sections to an amplifier without the need for a mixer. Stereo outputs send a pre-panned stereo image to a hi-fi system or the external inputs of a Roland Home Piano. Individual section outputs send each block separately to a mixer for more control of effects and equalisation, eg adding a delay machine to the melody block and equalisation to the bass.

As the MIDI specification allows for 16 MIDI channels other synthesizers or modules may be added but the MKS-7 Super Quartet provides an economical and compact start to a computer music system.