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UMI-2B MIDI Sequencer

UMI-2B MIDI sequencer running on a BBC B Micro computer.UMI-2B MIDI sequencer running on a BBC B Micro computer.

Recognised as one of the most user‑friendly systems around, this real‑time/step‑time MIDI sequencer runs on the BBC B micro and is gaining rapid acceptance amongst professional users for its versatility. Jay Chapman discovers why.

Scenario 1

You've managed to acquire, at great cost relative to your income, a couple of MIDI controllable synthesizers, hopefully at least one of them multi‑timbral. You've borrowed a drum machine from the guy next door and the dreaded overdraft is sufficiently small that the bank manager is expected to avoid cardiac arrest for a month or two. The ghetto‑blaster is seemingly to be locked forever in record‑pause mode awaiting the mega‑mix of your latest musical masterpiece. If only you had the necessary three or four sets of hands and could manage to play all the parts through correctly now and again — I mean take 12 is so tedious, not to say embarrassing! Oh, yes, and halfway through the fifth layer of sound‑on‑sound (the recording technique not the magazine!) you remember that the singer's voice dictates that the song must be played in the key of C# (how many sharps? — good grief!)...

Scenario 2

You run a 48‑track studio. You've spent thousands on digital multitrack recorders, computer controlled mixer, the latest outboard gear, aerobic baffle decompensators, cat‑flaps and so on, only to discover that the four letter word that has superseded PUNK is MIDI. Vince Clarke has just walked in with eight CZ101s under his arm clutching his latest epic on a floppy disk and the nearest size slot you've got is the post box on the front door...

Scenario 3

You've bought some hardware/software that acts as a MIDI control package.

Your problems vanish... well, ok, some of your problems vanish!


MIDI will not solve all of your problems of course, and it will in fact create some of its own. In general terms, like most tools of any trade, it is a combination of the quality of the tool and the competence of the person using it that dictates the level of satisfaction with the end product.

The success or otherwise of a MIDI control package must mainly be judged in terms of what it can do for the musical user and how easy it is to use.

Ease of use is particularly important since any powers of concentration that must be applied to using the package must be siphoned off from, and therefore ultimately detract from, the actual creation of the music. a further point to be considered in any review must of course be whether the item represents good value for money and I'm afraid this does not automatically mean that the item in question has to be cheap.

So, the question is: which MIDI control package? Hopefully, this review should help you consider the suitability of the UMI‑2B in the moments before the money burns a hole in your pocket or you pluck up courage yet again to approach the bank manager on bended knee.


Dedicated MIDI sequencers such as the Yamaha QX1 provide MIDI interface, software, computing power and data storage. The UMI‑2B provides the first two of these but not the last two. So, what else will you need as well as the UMI‑2B?

The minimum configuration required is a BBC model B microcomputer (or a suitably upgraded model A), a monitor or television and a suitable cassette recorder — if you already own these then the bill you'll be faced with at the end of the day just reduced considerably! However, price wars in the micro sector mean that ordinary model Bs can be found at considerably discounted prices and secondhand ones can be picked up for well under 300 pounds. The new BBC B+ and the even newer 128K version will also do the trick (though the UMI doesn't take advantage of the extra memory at the moment).

The BBC micro deals with computing power and short term data storage (ie. until you switch it off!) but what about the long term saving of song and other data? Well, it is possible to save songs and DX7 patches on either cassette or disk. Cassette storage is a real pain in the neck — it is slow and often prone to errors and I can't recommend it to professional users — or to my worst enemy, come to think of it. I hasten to add that this is a problem with the medium, common to all computer (synthesizer, drum machine) users who are forced to use cassettes for data storage, and is in no way a fault of the UMI‑2B. a decent data recorder, a cassette recorder purpose‑designed for use with a microcomputer, will cost about 30 pounds and give you far less heartbreak than the old valve reel‑to‑reel you've had stored in the loft since the end of World War 2. I used to use the cassette recorder in my hi‑fi — and there's always that Sony digital recorder if you're Scenario 2 (joke, folks, joke).

Floppy disks are the better choice for long term storage and, in common with most systems, you would be well advised to buy two disk drives for ease of making backup copies of all data disks — one disk alone could easily store hundreds of hours of work so making back‑up easy is not a bad idea. Double‑sided 80‑track drives will give you the largest capacity in terms of storage space but are more expensive than smaller capacity single‑sided drives. Note that a single‑sided 40‑track drive can still handle the storage requirements of the UMI system without problems — in fact, if you don't wish to store your musical doodlings, you don't need a disk or cassette drive at all because the UMI software comes in an EPROM that fits inside the micro.

For most BBC micros you will also need to buy disk interface chips and a Disk Filing System EPROM which were not automatically fitted in the BBC micro, although I believe the new BBC+ versions have the DFS kit fitted as standard. There are a number of different DFS kits available which are more or less compatible with the official Acorn product. The UMI‑2B is guaranteed to work with the Acorn kit and should work with the more compatible of the others — if it doesn't that's the fault of the DFS and not the UMI‑2B: so check out the DFS before buying! a minimum cost of perhaps 200 pounds for the complete drive/DFS combination should be budgeted for.

Coming back to the visual display requirements, it is worth pointing out that the UMI software uses the BBC's Mode 7 screen display which is capable of a similar display to that used in teletext‑based systems (such as Ceefax, Oracle and Prestel). This mode uses the least possible amount of the micro's rather scarce RAM — the standard BBC model B only has 32K bytes — which is needed for storing your song data, whilst still allowing the use of colour for text and limited block graphics. Colour is used extensively, and very effectively, by the UMI software and whilst the package can be used successfully with a monochrome monitor or television set, colour is definitely to be recommended!

As Mode 7 is a low resolution display, it's unnecessary to spend hundreds of pounds on a colour monitor as most portable colour televisions will do the job nicely. Once you have a micro other applications apart from MIDI (eg. word processing) are likely to come to mind which may require higher resolution monochrome or colour graphics so a medium resolution colour monitor might be a good idea if you can afford one.

Packing List

What do you get for your money? Well, depending on whether you've shelled out on the more expensive option or not, your trembling fingers should unpack the following items:

  • Aries‑B20 RAM expansion board, control EPROM and manual (optional extra)
  • UMI‑2B Operating Instructions Manual
  • UMI‑2B Interface (ie. the UMI hardware)
  • UMI‑2B EPROM (ie. the UMI firmware)

I'll discuss all of these fully in a moment.

If you're not really into computing buzz words then don't read the rest of this paragraph — it might put you off for life! The interface (or hardware) is the box shown in the main photograph with the blue button on top, electronics inside, legends identifying the sockets along the rear edge, and the two ribbon cables for connection to the sockets on the underside of the BBC micro. If you want to know why the term hardware is used, try dropping it on the drum roadie's head and observe what dents...

The EPROM is a chip which holds the UMI computer program (or software) that tells the computer and interface what to do to make them perform together as a sequencer. The EPROM is called firmware because it effectively encapsulates software in hardware — by the way you, the user, are the liveware in the system and, of course, your string vest is underwear!

As a final piece of suspense before discussing the UMI‑2B itself, let's consider the place of the Aries RAM board in the system.

Thanks For The Memory

It is very important in any MIDI control system to have sufficient RAM (memory that is readable and writable) available to store and edit a reasonable amount of music.

Whilst it would be possible to quote figures based on how many MIDI events a system can store, there are many variables involved which may qualify any quantitative estimate and perhaps a more useful measure is based on practical experience of the use of the system. Quite simply I managed to doodle happily over recording a song (typical chart single material), driving three polyphonic synthesizers and a drum machine (DX7, TX7, JX‑8P and TR707), without using more than 50% of the memory space available in the standard BBC micro — thanks principally to the song chaining facilities available on the UMI‑2B system (of which more later).

If you are into 20 minute epics which don't repeat verse, chorus, verse, middle 8 etc, and/or have a couple of 6‑voice multi‑timbral synthesizers and like to drive your drum machine live from your MIDI sequencer, and/or like to hear lots of sixteenth note triplets at 200 beats per minute, and/or you are well into St.Vitus dance on the pitch and modulation control wheels — not to mention delighting in the space‑grabbing horrors of after‑touch; then you probably will need more memory!

The Aries board extends the BBC micro's RAM by 20K (over 20,000) bytes giving far more space for your song data. By way of comparison, we can note that the Yamaha QX1 can use its disk drive to supplement internal memory during the playing of a song whereas the UMI‑2B requires the song data to be completely loaded beforehand. This means that the QX1 can handle far larger pieces of music than the UMI‑2B but, unfortunately, costs several times as much as the UMI‑2B!

Do You Have The Right Connections?

A typicla UMI-2B MIDI setup.A typicla UMI-2B MIDI setup.

For those of you who break into a cold sweat at the thought of changing a light bulb or, heaven forbid, taking the lid off your computer, don't worry: take your BBC micro along to the London Rock Shop. When you buy your UMI‑2B, they will fit the necessary bits inside the micro and show you how to connect the interface. Those of you with a bit more courage or a friend experienced in the art of chip manipulation, can do‑it‑yourselves. There is no soldering involved so care and concentration should carry the day.

If you have bought the Aries RAM board option, the BBC micro's 6502 processor chip is removed and plugged into the Aries board which then plugs into the socket vacated by the 6502. The EPROM supplied with the Aries board is plugged into a spare socket in the BBC as is the UMI‑2B firmware EPROM. If you have other (EP)ROM‑based software, you may find yourself running out of sockets — there are three spare sockets in the standard BBC micro — in which case you can fit a ROM expansion board. You may well need to do this in the future should further software, compatible with the UMI interface, be made available in (EP)ROM. Since Aries make a ROM expansion board, the Aries‑B12, that is compatible with their Aries‑20B RAM board, it will be possible to expand as and when required.

Once the case of the BBC has been closed after fitting the RAM board and the EPROMs, the interface is placed on top of the case and the two ribbon cables connected to the user port and 1MHz bus connectors. The instructions that come both with the RAM board and the UMI‑2B are very clear and no problems should arise.

The UMI‑2B Interface

As you can see in the main photograph, the interface itself is a rectangular box (30cms wide by 14cms deep by 4cms high). Its colour scheme of cream and brown matches the BBC micro's own and it sits unobtrusively on top of the micro beyond the keyboard and function key strip. The ribbon cables and any of the MIDI or other cables you use can easily be routed away from the six DIN sockets and seven 1/4" jack sockets on the rear face of the unit.

The interface is tidily designed, very well made and should survive a few knocks on the road. Internally, the circuit board is cleanly laid out, all integrated circuits are socketed, all but one of the wire links (used because this is a single‑sided PCB to keep costs down) are sleeved and there is no evidence of any last minute fudges to make the thing work — it's a clean machine! The DIN and jack sockets are board‑mounted which should improve reliability. The top of the case is easily removed (no flying cables to break and curse) should on‑the‑road repair prove necessary. The interface is powered from the BBC micro so it's on when the BBC is on.

The blue button just north of the UMI‑2B logo on the top surface of the interface is used to start recording of patterns in real‑time and to start and stop playback of individual patterns and songs. This represents a simplification from the original UMI‑1B's three buttons which experience has presumably proved unnecessary.

The interface features two 6850 ACIAs and therefore permits two completely separate MIDI circuits (for want of a better word) to be dealt with. So, if you have two MIDI synthesizers that can only receive on MIDI Channel 1, the UMI‑2B can handle them both. Each of the two circuits has two MIDI Outs in parallel so if one or two of your synthesizers don't have a MIDI Thru connection, all is not lost; also it is likely that most MIDI speed/response problems can be avoided by using the total of four MIDI Outs available rather than daisy‑chaining your synthesizers via MIDI In and Thru connections.

There is only one MIDI In which I felt was a pity since most keyboard players could sensibly handle up to two keyboards at once on real‑time recording, for example. However, this is a very small quibble and I have to compliment Umusic on the flexibility afforded by the MIDI connections provided.

The last of the six DIN sockets is a Sync‑24 output for driving any drum machine that conforms to the Roland standard. a trio of the 1/4" jack sockets are devoted to synchronisation of drum machines via the typical Clock In, Clock Out and Start/Stop connections. Clock In expects a minimum of 2 volts and Clock Out, Start/Stop, and Sync‑24 all generate normal 5 volt signals. It is possible to use the system's internal clock or to synchronise to an external clock. In the latter case it is possible to select 24, 48 or 96 pulses per quarter note as the clock rate to be recognised. So, the UMI‑2B can synchronise with many, if not most, drum machines and sequencers and in nearly all cases the system dictates the tempo which is convenient.

I was a little surprised to notice that the UMI‑2B does not actually send the MIDI real‑time codes required to drive a drum machine that could only sync via MIDI. Typically, such machines can actually be played direct (or 'live') via MIDI in the same way an expander unit can, so this should not worry most users.

Two more jack sockets are used to allow synchronisation with a tape recorder. The Sync Out sends a 3kHz signal gated on and off to the tape. Since 3kHz is an audible signal, Umusic suggest that it is possible to perform precise tape edits by reference to this 'sync code'. a tape synchronisation facility is not to be overlooked in a MIDI system since it can effectively multiply all but one track (the one with the sync code) on your tape recorder by the number of synthesizers available. I gave the UMI‑2B a good workout in this area and it worked first time and every time.

The last two jack sockets are designated Clik Out and Trig Out. Whenever the UMI‑2B is playing or recording, or you need a count‑in, it is possible to have the beats, or subbeats, emphasised by an audible click from the BBC micro's loudspeaker. Trig Out is simply a 5 volt pulse synchronised with Clik Out which could be used, for example, to drive a non‑MIDI sequencer. The click can be made to sound on every crotchet, quaver, semi‑quaver or their dotted equivalents.

The UMI‑2B Software

Well, you've been very patient to have read this far. The hardware is flexible and well thought out but it's the software that's the brains behind the whole operation. The software quite literally makes or breaks the whole package and I'm very pleased to report that Umusic and the software man himself, Lynton Naiff, are very much to be congratulated on this product!

The EPROM (mine was Version 4.17A) is packed with useful features. Quite literally packed, in fact, since only 52 bytes of the over 16000 available remain unused!

Main menuMain menuThe main menu is shown on the right and, as you can see, colour is used very effectively to highlight different sections of the screen and to group related choices together. Displayed on the left of the screen (above the version message) are the main menu options used during recording and playback. Selection is by pressing one of the BBC's 10 function keys (fO through f9) and the correspondence is quickly learnt. In normal use, it is not even necessary to keep returning to the main menu page and moving from option to option directly becomes quite automatic.

The first point to make is that because the software is in a EPROM inside the BBC micro, it doesn't have to be loaded from tape (very slow ...) or disk (fast — but you have to find the disk and the software would take up 16K bytes of your valuable RAM). In fact, it isn't loaded at all — the correct ROM socket is switched on and control of the system handed over. All you have to do is switch on the BBC micro and monitor and type *UMI followed by the RETURN key. Very quick, very efficient and dead easy!

Default values for the length of the sequence pattern, the click frequency, the count‑in length and so on, are easily altered from the main menu with the cursor keys being used in a consistent manner throughout the system to select and alter parameters. The defaults section can be seen in the lower right quadrant of the screen in photo 1. Note that it is possible to make the system ignore keyboard after‑touch when required, since masses of memory‑eating data is transmitted by a Yamaha DX7, for example, if you happen to be a little heavy‑handed when playing but are not intending the DX7 to actually respond to after‑touch.

Pattern Recording & Editing

Real‑time recording follows a click count‑in (once the button on the interface has been pressed) of up to nine beats or can auto‑start when you start playing the synthesizer. Once the tempo is firmly established in your head the auto‑start option comes into its own. It is possible to have up to four patterns playing simultaneously during recording which lets you get into the feel of the music as you build up the piece.

Real‑time recording, Step‑time recording, Edit optionsReal‑time recording, Step‑time recording, Edit options

In a future release of the software you will be able to supplement the count‑in with the playing of the pattern leading up to the start of the one you are about to record. As soon as the pattern is recorded it loops until the button is pressed again and can be sent out to any specified MIDI channel to try out on the different synths attached.

The pattern can also be sent out to all synthesizers during recording which is useful where two or more synthesizers contribute to one sound as otherwise, the musician would have to imagine the overall effect or would have to keep swapping MIDI cables about between recording and playback.

If you overrun the pattern length, which could leave notes hanging on, there is an edit option to tidy the pattern end up for you. If you are unhappy with the result of your real‑time virtuosity it only takes one key press to prepare to re‑record the same pattern with the same simultaneous patterns playing; again the system shows its efficiency and ease of use. Don't forget that it is always possible to reduce the tempo for the difficult bits and bring the piece back up to speed later. Furthermore, you can build up the pattern by overdubbing. Each overdub can consist of more notes being played, and/or the introduction of extra pitch bend or other controller information and even patch changes! Only when you are happy with the overdub is it merged permanently into the pattern. As with many real‑time input facilities there is the ability to auto‑correct (round off) timing errors to a variable precision — this is an edit menu option.

Step‑time entry is also catered for and again the option is very easy to use. Your main synthesizer's keyboard is used to toggle notes on or off on the five column (one per octave) display in the upper left of the screen and you then assign a key velocity value, if required, and the number of steps (or a gate length of 10%, 30% or 75% if the notes are to be less than one step long) to the note or chords selected. This use of a musical keyboard, rather than the micro's QWERTY keyboard, for note selection is definitely to be recommended.

Once one of the 127 available patterns has been filled via real‑time or step‑time input, it is possible to edit it. The edit options are shown below. Option 0 (erase notes) uses a 5 octave grid in a similar manner to step‑time input and steps you through the pattern (from chord to chord not step to step) playing the notes which you toggle off to erase them. The combination of step‑time input, real‑time overdubbing and erase deals quite satisfactorily with most editing requirements but is occasionally a little tedious eg. the only way to adjust key velocity with any accuracy is by re‑entry of the whole pattern in step‑time. Alternatively, since re‑entry even quite a few times via overdubs (assuming a velocity‑sensitive keyboard) is so easy, most people will not see this as a real problem.

Erase, Channel/track assignment, Write/edit chain.Erase, Channel/track assignment, Write/edit chain.

As has been mentioned, the use of MIDI pitch bend and modulation controllers eats memory in prodigious gulps and the UMI‑2B thoughtfully provides some succour via the pac mod and pac bend options which gradually reduce the number of bytes devoted to a controller effect. Each time the user applies a pac, the pattern can be replayed to judge whether the controller effect has been lost or damaged. In this way, the optimum use of memory is assured. If a pattern has been successfully recorded in terms of the notes played but a pitch or modulation effect was messed up, it is possible to erase just the effect (and to re‑record it via an overdub of course). If any of the auto‑correction, pac or erase controller facilities have been used in error then the retrieve option will undo the damage.


In a nutshell — phenomenal! One of the principal reasons that the UMI‑2B manages with a fairly small amount of RAM is its chaining ability. Patterns, containing up to 127 note polyphony (if your synthesizers can handle it), can be copied, transposed, played serially and in parallel tracks and looped to order. All of the 16 tracks can be assigned any of the 16 MIDI channels and the load of sending out 16 tracks‑worth of sequences over MIDI is split between the two ACIA's in the interface avoiding MIDI speed problems.

The first track is used as a navigation routemap for the UMI‑2B. This is an important feature if tracks are to be mainly silence (just a bit of brass on the end of the chorus, for example) so you don't waste memory storing the silence — the navigation track will kick the relevant pattern into action at the right moment.

You can define repeat sections with first and second time bars, or repeat to fade, as well as both coda and sign sections. When putting the chain together both insertion and deletion of patterns is possible making song building extremely easy. Chains can be copied to other chains with both transposition and pattern offsets applied. The pattern offset cleverly allows related patterns to be played in parallel from different tracks (and therefore MIDI channels) so that if you write the bass lines corresponding to the keyboard patterns 1, 2 and 3 on patterns 11,12 and 13 then the bass track is just a copy of the keyboard track with offset 10‑cunning, eh?!


There is a Notes page for you to keep track of what synthesizer is supposed to be playing what sound, on what track, and this information will appear at various points in the package to help you confirm that you're doing what you think you're doing! For example, if you specify a pattern to be played back when you are doing a real‑time recording, then the name of the synthesizer that the played pattern will be sent to, will appear in the green box. a nice feature for use on the road allows auto‑loading of a song specified on the Notes page so if each song contains the name of the next one then a single key press will load the next song in seconds from disk.

The current software allows the saving and loading of complete songs which is an obvious requirement. Unfortunately, individual patterns and the UMI‑2B's performance parameters (all those default values which you may have modified, like the pattern length and click frequency) cannot be saved separately on the version I had for review. Pattern saving can be particularly important when you need memory temporarily for an edit (which will then be freed) in order to hold the whole song in order to play it. Also you may want to transfer patterns from one song to another. These features are to be made available soon in a future release of the software.

The current software also boasts a DX7 voice dump facility which I understand is to be generalised to other synthesizers in the future. For the moment, a single voice or a full bank of 32 voices can be loaded or dumped and the London Rock Shop can supply a set of 10 floppy disks containing some hundreds of new voices in related sets (brass, pianos, guitars, etc) for the DX7.


To be honest, my first reaction to the UMI‑2B was that it seemed very expensive — particularly if you have to buy a BBC micro! Somewhat grudgingly at first during the review period, I had to admit to myself that value for money, and not just the actual price, is what matters.

For your money, you will get a highly professional product which does exactly what it sets out to do in a very efficient and extremely user‑friendly manner. It is worth considering the point that the whole setup, computer and all, costs less than many of the synthesizers that it will most probably be used to control! The system is continually being enhanced through software updates and has the professional and enthusiastic support of the London Rock Shop. Highly recommended.

The UMI‑2B system costs £495 inc VAT without the Aries memory expansion board, and £575 inc VAT with it.

UMI Users

UMI users Vince Clarke and producer Eric Radcliffe.UMI users Vince Clarke and producer Eric Radcliffe.The UMI system has found favour with such artists and producers as Blancmange, Alan Parsons, Mutt Lange and Tears For Fears producer Chris Hughes. Not to mention Vince Clarke (of Depeche Mode/Yazoo fame) who took time out from making his new record with producer Eric Radcliffe to supply a quick input on the subject:

Vince: "If you are looking for something to sequence, say, a bank of eight Casio CZ101s, then UMI‑2B is the answer. I tend to use my UMI for overdubbing."

Eric: "I use it for entire songs having all 16 MIDI channels running. The UMI‑2B gives me a home system whereby I can hear a complete song on a few inexpensive keyboards so that I can check that the music is right before I come into the studio. It saves me money because we now spend more time in pre‑production and just turn up in the main studio with our floppy disk, plug into another UMI‑2B, and we're off and running. It can save weeks of studio time at X pounds an hour, and I shouldn't really say that because we own two recording studios!"

For a player's view of the UMI‑2B, read what songwriter/performer Paul Bliss has to say about it here.