• The MC-202 MicroComposer
  • The MC-202 MicroComposer
  • The MC-202 MicroComposer

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The MC-202 MicroComposer

MicroComposing with Roland

The new MC-202 MicroComposer examined in depth



Roland's introduction of their first Micro-Composer, the MC-8, in 1977 was undoubtedly ahead of its time and, like most new ideas, its great potential was little understood or accepted by musicians and studio engineers. As the Compu-Age grew rapidly around the MC-8, the awareness of the possibilities that micro computers offered for practical music-making (rather than just with mainframe machines), brought increased acceptance of this dedicated computer music instrument.

The concept of the MicroComposer has not changed since it still is a digital sequencer controlled by a microprocessor. The emphasis of the MC-8 was on programming by calculator keyboard up to 8 separate sequences that provided the necessary control voltages for external analogue synthesisers. The MC-8 cost around £4,000 in the UK and its editing facilities made it a powerful composing tool — allowing less articulate players to perform 'note perfect' music, provided they were willing to learn musical notation and the simple programming language.

The MC-4, introduced some 3 years later, was less expensive at around £2,000 for the basic unit and allowed real time, as well as 'step' keyboard input via an external synth. Although only 4 separate voice lines are available, the second CV can play different notes for each of the 4 sequences or add filter/amplifier control. Many editing features are also available to easily programme complete pieces of music that can be stored digitally or via mono cassette.

With home computers, home recording and, particularly for us, home music-making becoming almost a new way of life for many — without a lowering of musical quality — the electro-musician has become as much a composer as a player. The size of instruments has reduced significantly through micro-technology, with even the keyboard affected. Already a tremendous price drop has been seen with Roland's Amdek Compu-Music machine, the CMU-800 at around £400, for musicians already owning home micros such as the Sharp or Apple II. This system is a purely 'keypad' inputting device that makes the complete 'band' from numbers, and was reviewed in the February '83 issue of E&MM.

Compose anywhere



Roland's MC-202 MicroComposer represents yet another step forward in a compact portable design that lets you create music anywhere. Its price is only £365 (inc VAT) — that's low considering it contains a full monophonic synthesiser with built-in moving rubber pad 2½-octave keyboard, and two independent digital sequencers. Sequences are entered either in real time or by notes as 'steps' which are later edited to correct length, rests, etc. Any external 1V/oct, 5-15V trig synth can be hooked up to record or playback with the built-in synth or play the other channel on its own.

There are numerous editing possibilities and external in/out sync to drum machines, plus saving of sequences on standard mono cassette recorder — and a sync 'clicktrack' as well for tape control on playback. Plug in your stereo headphones and wherever you are you can compose your music!

Unlike other portable keyboards that offer melody recording and playback, the editing via the liquid crystal display and the direct communication with analogue and synth-controlled machines puts the MC-202 into a special category of its own for the more serious musician. Because the external tape sync will set the correct tempo throughout a played-back sequence, it's possible to use the built-in synth to create a multitrack recording just with something like the new portable Fostex Multitracker added to it.

Layout



The MC-202 is lightweight and small, measuring only 13½"(W) x 8"(D) x 2" (inc knob max H). It is constructed in grey plastic with white labelling. Across the very top of the front case are all the rear connection markings from left to right: 9V DC input socket (Boss AC adaptor PSA 100) — when not in use, 6 x 1½V (size C) batteries are loaded into the rear of the case (Roland even have their brand name on batteries now!); Sync In/Out (5-pin Din sockets) enabling Roland instruments such as the TR606, CR8000 and TR808 drum machines to control the sequence start and hold sync'd tempo (or vice versa) — the CSQ-600 (to MC only), MC-4, and the TB-303 (from MC only) also; the calibrate screw driver-adjusting preset for tailoring the overall pitch when using other synths; 2 x 3.5mm sockets for separate mono cassette recorder 'Memory Save/Load' and 'Sync In/Out'; 6 x 3.5mm sockets for connecting an Ext 1V/Out synth (CV & Gate In), Built-in Synth CV/Gate Out, Ext Synth CV/Gate Out; a stereo headphone (8-30 ohms) socket and finally a standard jack line output for the built-in synth.

The top section of controls are for the synthesiser with small variable or switch sliders. All 5 rotary controls are placed across the centre with the Power On/Off pushswitch, for Tune (adjusting overall pitch +/- 1 semitone), Portamento, Tempo, Accent and Volume. At the centre of the instrument is the focal point of the system — the LCD display.

The lower part of the case has momentary rubber pads that make switching contact with conductive rubber. The MC-202 scores here over its larger versions, because the keyboard-style layout makes it easy for the musician to enter the correct pitch without resorting to looking up numbers directly — even so, as a key is played it will be given a code in the display, from 1F to 6C, representing the note's octave and letter name. Larger blue pads select the operating modes and edit functions, while these and the keyboard buttons with the shift key are each allocated a second assignment. Over 60 separate functions are therefore definable in this lower part that communicates directly with the micro system.

The internal circuitry is on one main PCB with a separate keyboard contact PCB and rear connection strips. Construction is very neat and compact, with only a few wiring connections. The synth oscillator is based on the Curtis 3340 chip that seems to get in most instruments these days. CMOS circuitry is used throughout with low noise op-amps (TL062 and TL022) for signals. The display/driver is a non-standard type specifically for the MC-202 and the biggest space-taker is obviously the row of 6 batteries.

Left hand keyboard and blue function buttons.


Operating Modes



There are basically two ways you can play back and three ways you can record with the MC-202.

Playback can either be directly from the mini keyboard which directly controls the built-in mono synth, or it can be a replay of one or both of your programmed sequences. If it is the latter, the keyboard does not also function, but it is possible to use an external synth (1V/Oct) to send its CV and GATE outs to drive the built-in synth. What is more likely, is that you'll hook this in to be able to record in real time.

So the recording of melodic sequences is done either in real time using the built-in synth keyboard (or ext synth keyboard) or by a 3-stage process where you first enter the note pitches from the keyboard (as slow or fast as you like) in 'step' fashion, then enter the correct step time, and finally the gate time. Various editing functions help you to correctly enter the desired sequence. The third way enters pitch in step as before, but then enters the correct rhythm by simply setting 'Tap' mode and playing the right time lengths (as your entered pitch notes follow automatically) using two 'Tap' buttons.

Two sequences can be recorded, called Channel 1 and Channel 2, with 2729 notes (ie. complete events) available to be shared out between both. In real time mode, whilst a second sequence is recorded, the first sequence can be heard as well, provided you've got an external synth connected. A second synth can also be connected to duplicate the built-in synth if you wish.

Once programming is completed (and before switching off, as there is no battery back-up!), sequences in the internal memory can be saved on mono cassette for later recall. Since composing is likely to take some time, a 'Power Save' function conveniently turns off all operation and simply retains the internal memory intact until you're ready to continue. As mentioned, a tape 'Sync' track can also be saved.

LCD Display



During all microcomposing recording and playback, the special LCD display is the focal information centre of the system, relaying to the user all function commands given, and enabling every note in a sequence to be 'analysed' as a numerical output of pitch, step and gate times. Measures can be accessed to be copied or deleted and have notes changed, inserted or deleted. Once a sequence is completed, it can be made to 'cycle' (loop) from beginning to end repeatedly at the tempo you've set. Each note can be given an accent (with the level set for all accented notes by the Accent control), and portamento between two notes can be specified (at the rate set by the Portamento control).

The oblong display has seven horizontal segments which appear as numbers, dashes, or small blocks. There is also a small dot at the bottom right that serves to indicate the tempo by turning on and off at the rate set. At other times it will simply stay on or disappear altogether to verify function operation.

The first segment (from left to right) contains small blocks to indicate the particular mode you have selected — either PLAY (by pressing the Play button) for playback in the ways described, or PITCH, STEP, or GATE which are EDIT modes required to record in real time, tap or step methods described. The latter three also enable editing to take place. Selection of one of the Edit modes is in 'cyclic' fashion, so pressing the Edit button will step through each mode, looping back to the first and so on.

The 2nd segment indicates the channel selected by the Channel button. Changing from one channel to the other can be at any time between recording or playback, and the built-in synth only responds to the channel number in the display.

The 3rd segment has three appropriately shaped dashes that show the pitch range of the keyboard: down 1 octave, normal pitch, or up 1 octave. This gives the MicroComposer an extended keyboard range of 4½ octaves (F to C, coded 1F-6C). In Step mode, this segment changes to show the type of note played code (rest, staccato, etc).

The 4th, 5th and 6th segments show the alphanumerical data for the particular function at the time. Sharp or flat notes also have an upper or lower dash indication, with selection of sharp or flat key coding able to be preset at any time for a corresponding change in the code output. If special commands are given, the screen data will change accordingly and revert back to the current mode (Play, Pitch, Step or Gate) afterwards.

The final segment contains 4 small independent blocks that indicate the CYCLE (loop) function is on (by pressing Shift then Cycle); BATTERY — if the voltage has dropped significantly below 9 volts, this will come on; PORTA shows the current note has Portamento on it; ACC shows the current note has an Accent.

Right hand keyboard and blue function buttons.


MicroComposer Functions



Just to make sure I don't miss any of the specific functions on the MC-202, I'll deal with these in list form, with basic descriptions of each as necessary. This may seem a little over the top — in fact, some might say it's not a review but a copy of the manual. I can assure you this is not the case, as no manual was available — the comments are therefore based purely on the practical results achieved.

All processing is done via the blue buttons and/or the actual keyboard button. Since both these sets of buttons nearly all have a dual function, made by pressing the SHIFT button directly before and during the pressing of a chosen command, the second function is clearly marked in white above the button required. The ENTER button, like standard micro systems, makes the selected data entry complete, and most correct functions' entries are indicated not only in the display, but also by a high-pitched short 'beep' (Sinclair's 'Spectrum' may have been an influence here, and in the rubber buttons). The beep can be turned on or off as you wish (by pressing Shift with Bar) as it is generated internally and is not output on headphones or line output. Whilst in EDIT mode, the current measure (ie. bar number) is displayed by pressing the SHIFT key alone, so you always know where you are in a sequence.

Recording By Step

On Power switch-on, the MC-202 enters Edit/Record PITCH mode, Channel 1, Measure 1. The built-in synth is set up to produce a sound, and the TRANSPOSE buttons are used to set the keyboard octave range for NORMAL, UP or DOWN. Now your sequence melody (ie. the 'pitch' data) can be entered from the keyboard. The code for each note will be shown on the display as you play. A new MEASURE is inserted by pressing the BAR button at the right point in the sequence.

First Playback

With rotary volume level set appropriately for headphone or external monitoring (via the line Output socket), pressing PLAY then START will begin playback. During this time, the LED above the Start button will remain on. The Tempo can be adjusted at any time, and pressing the CONT/STOP button will halt the sequence and enable you to continue from that point later. Pressing Start will always begin the sequence at Measure 1, Step 1.

Playback at this time will be in regular equal steps according to the clock Tempo set. If you want to see the tempo, simply press TEMPO (between operations) and a readout on the display from slow to fast is given in steps of 2 (from 36 to 300).

Changing the STEP time

Both STEP and GATE have 'default' modes (Step=24, Gate=24), as do many other functions, otherwise a lot of setting-up would be necessary before recording.

Changing the Step time (the time between notes) is easier than on the MC-4, simply by the addition of selectable note values with the first 9 white notes of the keyboard. So correct note lengths can be conveniently entered as you see them on the music! Alternatively, a number can be entered by using the remaining white notes numbered 0-9. Either type of entry is completed by pressing the ENTER button.

Code Values are allocated as follows: Semibreve 192, minim 96, crotchet 48, quaver 24, semiquaver 12, demisemiquaver 6, crotchet (1 of a triplet) 32, quaver triplet 16, semiquaver triplet 8. Maximum entry is 239.

A lot of extra information is entered in Step mode:
1. Note lengths are entered as described.

2. The first 5 black notes can be used to enter an appropriate Gate time (the actual time the note remains on — or in 'sustain' on the built-in synth): 0=Rest, 1=Staccato (Step time ÷4), 2=Non Legato (Step ÷2), 3=Legato (¾ Step), 4=Tie (Gate=Step). In real time it defaults to code 2.

3. Portamento can be added to a note using the PORTA button.

4. Accent can be added to a note using the ACC button.

5. Programming of Step data is completed by pressing ENTER.

Changing the GATE time

If you've used the best option of entering a certain type of note by the direct 'keyed' note value, you'll not need to use GATE mode. However, for special settings or tidying up of real time input, this mode allows numerical entry of GATE time, using the keys numbered 0-9, followed by the ENTER button. The maximum number is 239, but depends on the type of note entered ie. rest, staccato, tie etc.

Internal circuitry, with keyboard/display PCB at front.


Recording Real Time Sequences

Preparation for real time recording is done in Pitch mode by pressing Shift with the Real Time button. Then a numbered key 1-9 is pressed for the number of beats in a bar followed by the Start button (with Shift still held). The internal piezo unit immediately provides high-pitched sounds on 3 notes with main beat, remaining beats and halfbeat pulses on a clear 'metronome' for 2 bars. Then the Start LED comes on for the bar counting to begin as you record by playing the keyboard notes.

All Pitch, Step and Gate data is recorded and can be examined with the 3 Edit modes as described earlier. A rest will contain the previous note Pitch (or default 3C) and Gate 0 (plus correct Step value).

Add a 'TAP' Rhythm

An alternative to entering codes for Step and Gate, or for correcting a real time rhythm (without changing Pitch) is to use two 'Tap' buttons. Pressing Shift with the Tap function button (in Pitch mode) starts the metronome again. A time signature can be redefined, by entering a new number from 1-9 before pressing Start.

Stopping both Real Time and Tap recording will always occur at the end of the current bar (with an extra beep added on the first pulse of the next available bar).

Special editing functions

Cycle (+ Shift). Allows continuous looping of sequences on playback but is not operative in EDIT modes and is not stored with sequence on cassette. Cycling with Tape Sync will work as long as the sync pulse is still running.

Delete (Step or Measure + Shift), followed by Enter in Pitch mode. Deletes displayed note (next to be sounded) or current measure, and a 'd' appears instead of Channel number.

Insert (+ Shift), followed by keyboard notes and/or Bar lines required, then Enter. Inserts notes in step fashion prior to the current note 'I' is shown.

Copy (+ Shift). In Pitch mode this will copy bars onto the end of the current sequence (all information, including Accent and Portamento for each note). The 'start' measure is located, followed by Shift and Copy. Then the Enter button is pressed for each next bar to be copied 'C' is displayed.

#/b (+ Shift) gives either sharp or flat note code simulation, eg. 3F‾ or 3G_= F# at 3rd octave up.

Accent (+ Shift) in Step mode. Opens up the VCA or both VCA and VCF to give a volume accent with or without a brighter tone on the current note (shown as A or FA on display).

Memory Check (+ Shift). Indicates number of note events left out of maximum 2729.

Step (+ Shift). Indicates in Play mode the total Step count for the Measure.

Using Back or Forward Step buttons in any of the Edit modes, you can step through your sequence note by note. As you step back, any bar lines will sound a double beep. Then the pitch of a note can be re-entered to correct it, and Gate or Step values can be changed. Two further buttons also step backward or forward measure by measure. The display always indicates the current measure until these buttons are released.

You can also jump to a measure by pressing Shift, keying in the bar number and pressing Enter. If you go to a non-existent bar, the last bar will be recalled.

You can add to your sequence bit by bit by starting at the right measure (ie. current measure = entry point). You can't insert in real time, but you can as mentioned correct a passage by starting it at the incorrect measure — although you'll lose all original data from that point on. If you reach the end of the memory you're also likely to corrupt previous data input. Error entries are indicated by 4 beeps!

Incidentally, if one sequence is longer than the other, both sequences will cycle over the longer sequence. As the length of a sequence increases, the function commands will become slow to respond. And you can't hear one channel while you record another in Step mode, only in Real Time.

Rear view of the MC-202.


Tape Memory and Sync



Both sequences can be stored in one tape dump onto standard mono cassette recorder, using the SAVE (+ Shift) function in play mode. A Start tone (mid D) is generated on the tape output and when the Enter button is pressed, becomes a higher D. 'S' is shown on the display, the Tempo dot stops flashing and the current displayed data will disappear until saving is complete.

Loading the stored sequence with the LOAD (+ Shift) function is done in a similar way. (Display shows 'L'.) Verifying the tape transfer is done with VERIFY (+ Shift), displayed as 'U'.

After all three tape operations, the MC-202 will beep and return to current status. Save time varies with the amount of data stored (up to 2¾ minutes for full memory). Errors give 3 beeps and the display returns to Channel 1, Measure 1.

One very useful feature is the addition of TAPE SYNC. Once you've saved your sequence, you can put a Sync track onto a multitrack or even your mono cassette machine that will remember all your tempo changes and precise start and stop. Laying down the Sync track on tape is simply done by starting your tape machine to record and then operating MC-202 playback.

Running a sequence from Tape Sync is also easy and is done by pressing Shift + Tape Sync buttons, starting the tape recorder to play back, then pressing Start during the opening tone. The red start LED comes on until the tape sequence timing data ends, or you press Stop. By holding back pressing the Start button, you can jump into a Sync track signal.

Synthesiser



This is a standard monophonic (low note priority, multiple trigger) analogue synthesiser with controls divided into 6 labelled sections as follows. The Source Mixer provides 2 mixable basic waveforms: pulse and sawtooth (falling ramp). A sub-oscillator can also be mixed that can either be switched to one or 2 octaves down from the basic pitch as a squarewave or as a 2-octave down pulsewave. Each of the sub-oscillator types are pulsewidth modulated by the VCO Modulation slider over approximately 50%.

The VCO section sets the pitch of the 2 basic waveforms, switchable to 16', 8', 4', 2'. With the sub-oscillator 2 octaves down, this gives a deep 64'. Pulsewidth is variable by setting the Pulsewidth slider manually, by switching to LFO triangle modulation (but with no delay), or to modulation from the envelope shape set by the ADSR controls. The latter control will reduce the pulsewidth to zero (no sound) on maximum peak (with Sustain up full).

The pitch can also be modulated by the LFO with or without delay up to one second. The rate is variable between 1 cycle over 9 seconds to some 20Hz and the red LED gives visual rate indication.

The VCF section has standard analogue control for a low pass filter with 24dB slope. Cut-off frequency will tailor a sawtooth/square mixture into a near sine shape. Resonance will put the filter into oscillation at maximum settings. As the battery voltage drops, modulation interference is noticeable here, as is a slight pitch change on release of lower keys in particular. Also a result of this, the overtone changes during the filter sweeps are not as smooth as with full power operating. Other VCF controls are for amount of Envelope control, LFO Modulation depth, and Keyboard follow effect.

The envelope sets the amount of filter cut-off change from the Attack, Decay, Sustain and Release sliders. Maximum Attack is 1.7 seconds, Decay is 9 seconds, and Release is 11 seconds. The VCA can be switched to be controlled either by the envelope ADSR settings or by an organ-type on/off gate.

Portamento only operates with the Micro-Composer, although the tune control adjusts pitch +/- 1 semitone and the volume control adjusts the final output of the synthesiser at all times.

Summary



The MC-202 has to be regarded as a desirable package because it offers the whole microcomposing process in one very neat portable instrument at significantly low cost. Obviously, the keyboard format is a compromise that will not deter the budding Tangerine Dream electro-musician, although it is not too easy to execute tricky passages in real time. The bonus of a built-in synth far outweighs this problem anyway, and as the Roland people will no doubt point out, it's really meant to let you edit precisely with something we all know — the keyboard, rather than strings of unfriendly number codes alone.

At first the advantage of a second sequencer without a built-in synth seems to defeat the object of the complete package concept, but it is very useful when using multitrack techniques with the Tape Sync facility for playing back two parts. I would have liked Tape Sync in record as well as playback, but preliminary trials show it's still possible to use the MC-202 with a multitrack machine to layer tracks. (Lay your Sync track, Chan 1, then use Tape Sync to add Chan 2. Delete MC Chan 2 and make a new Chan, using Tape Sync to add this new Chan 3. Carry on!) Also, the cassette input for Load and Save requires a high level drive, like most micro systems. That means most cheap cassette machines work fine, but a simple driver interface had to be added to the Fostex Multitracker, for example, to give sufficient input gain. (Write to E&MM if you want the one-chip circuit costing a few pence.)

There's about 8 hours constant usage on batteries, although in the review model a 1½V drop made the synth completely unstable, even though no battery 'low' sign was observed. Driving an external synth can also be a problem with reduced battery voltage, so Roland's 9V adaptor is recommended. (Roland also sell a nice light pair of headphones, type RH-10.)

For the number of microcomposing functions available, it's a remarkable little machine, especially for its keyboard-orientated operation which should attract many more 'players' to the micromusic world. Synthesiser quality is quite exceptional for an analogue instrument — the lack of a second oscillator is partly compensated for by the sub-oscillator and parameters are good enough for the MC-202's main purpose — sequencing.

Composing is very easy (much more so than using the Spectrum micro in terms of function access!) and the dedicated LCD (angled towards the player) has no drawbacks whatsoever. One important function missing is repeating parts of the sequence without using more memory — the Copy function will repeat passages, but still uses up more notes. Processing time does get rather slow as you use up memory, with a wait of several seconds between function operation. A 'memory full' indication and operation halt should have been included in the software. It's also very easy to switch off without thinking about saving your sequence on tape, so beware! Since two Sync outputs are provided, it's easy to link Microcomposers together — maybe Jean-Michel Jarre will swop his rack of EMS Synths for MC-202's!

Some people say that stand-alone sequencers will soon be outdated by synthesisers with software able to do all the sequencing you'll need, but Roland's MC-202 is sure to inspire the imagination of many people making music at home because it is a computer with a synthesiser — so now you've no excuse for not joining the Compu-Age!

For further details contact Roland (UK) Ltd, (Contact Details).


Also featuring gear in this article



Previous Article in this issue

Concert Review

Next article in this issue

Carlsbro Cobra 90 Keyboard Combo


Electronics & Music Maker - Copyright: Music Maker Publications (UK), Future Publishing.

 

Electronics & Music Maker - May 1983

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