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Disk Recorder / Sequencer

Mark Jenkins gets to grips with this unassuming dual channel MIDI sequencer from the States and unearths some interesting facts...

Behind the smoked perspex cover of what seems like an innocent looking disk drive are hidden some advanced MIDI composition and recording facilities. Mark Jenkins investigates...

At first glance the MIDI DJ, the first music product from America's Indus Systems/National Logic, looks like an ordinary disk drive with a couple of chips' worth of MIDI software tacked onto the back. And that's almost what it is (good to have your first impressions confirmed occasionally!).

But that simplistic description of the DJ doesn't give any idea of its versatile applications as a sequencer and MIDI data filer. This little black box, which sells for around £450, has some potentially very exciting capabilities.

The background to the DJ is rather odd. Having been available in the States for almost a year now, it has been picked up by sole distributors Future Music (Chelsea) who found that the American manufacturers had no plans to export the unit to the UK at all. In the US, the MIDI DJ is selling like hot cakes, with many performers buying two or even three of the units. And the company that manufactures them, which has in the past specialised in disk drives for IBM and compatible micros, is owned by a tycoon whose other main claim to fame is that he manufactures toothbrushes by the million for Colgate!

So, is the MIDI DJ a musically sophisticated item? The answer to that question has to be "Yes", because behind its deceptively simple exterior - just four control buttons, a display and a disk slot under a smoked perspex cover lie a multitude of advanced composition and MIDI recording functions.


The MIDI DJ has three main applications:

1. As a conventional MIDI sequencer, recording polyphonic performances and overdubbing them in the usual fashion for playback 'live' or synchronised to tape via a drum machine.

2. As a data filer which will let you store (for instance) DX7 sounds on a cheap 5 1/4" floppy disk rather than an expensive RAM cartridge.

3. For those interested in playing live, as a playback machine for sequences which have been created on a much more complex system such as a Steinberg Pro-24/Atari ST set-up.

As mentioned, the physical appearance of the MIDI DJ is simple. On the rear panel are MIDI In, Out and Thru sockets, a socket for an external power supply, a set of DIP switches to alter the synchronisation pulse rate, and three jack sockets for Sync In and Out and a Stop-Start footswitch.

On the front panel there's a four-character LED display, a disk slot with a locking lever, and four control buttons which give a satisfying click when operated. These are marked: BKW(<), FWD (>), START and STOP. You'd think that all the multiple functions would be accessed using different combinations of these four buttons, but this isn't exactly the case.

What, in fact, happens is that the four buttons double as cursor keys (like those on most home computers) - up, down, left and right. They aren't currently marked as such and it would be most helpful if they were, but you can always put a couple of stickers on them yourself.

Once you've grasped the fact that the buttons double as cursor keys, you can steer around the MIDI DJ's functions using a large flowchart supplied with the owner's manual.

BKW and FWD steer left and right, while START and STOP steer up and down. Navigating yourself towards the main features of the function flowchart is quite rapid once you've got the hang of it.

Let's give an idea of how the DJ's flowchart operation system works. The start-up function is Entr, short for Entertainment Mode - of which more later. If you use the FWD button you'll scroll past the following functions:

dISC, PLrc, Edit, CnFG, bEAt, trAn, CLOC, GAtE, Ctrl, dEnS, CHAn

As you may have guessed, these refer to the DJ's Play/Record, Edit and Configure disk functions, which includes the Beat, Transpose, Clock, Gate, Control, Density and Channel functions. When you reach one of these functions, you simply use the START (Down) button to access their various section levels, and then use Left and Right again to set values such as MIDI channel number, tempo, and soon. Let's take a look at some of these functions in detail...


The Entertainment Mode plays each of the 12 songs available in the MIDI DJ's memory, one after another. The Et function available immediately beneath it on the flowchart refers to relative tempo, and lets you programme tempo changes from +99% to — 9% between songs.

Under the dISC function you'll find LOAd (files 1-127), SAVE (pattern with tempo and time signature), rEPL (replace a pattern), dELE(delete a pattern), COPy (copy an entire disk, which is done in four or five sections), and Init (format a blank disk).

Under the PLrc section you'll find most of the basic recording and playback functions of the MIDI DJ. Like the Yamaha QX7/QX21, the sequencer functions are based on the idea of working with two channels (tracks) - one for recording and overdubbing, and one for storing the mixed results on. You can combine the contents of Tracks 1 and 2 onto Track 2, which erases Track 1 ready for further recording. You can also copy Track 2 to Track 1 to permanently transpose a pattern, remove MIDI channel information or (combined with the Edit function) build up repeated patterns.

Under Edit you'll find room to enter the first and last measure to be edited, the tracks to be edited (1,2 or both), the number of measures to be inserted or deleted, the auto-correct resolution from whole notes to 96th notes, and the density of each track. Density refers to the amount of MIDI information recorded and thus the amount of memory used up per pattern - the options are: Short Play (all MIDI information including notes, velocity, pitch bend and controllers), Long Play (notes and velocity only), or Extended Play (notes only).

Mirage owners should feel right at home with the DJ as some features are represented by hexadecimal numbers (base 16). For instance, the 1000th bar recorded will be shown as A00 and the last pattern in the edit range, 1699, as G99. Similarly, MIDI channel 12 is shown as C. This could be frustrating, but it hasn't put off users of the Ensoniq Mirage.

Onto the bEAt menu, which allows you to set a tempo from 1-255 bpm, switch the metronome on/off, set the beats per measure, define a length for the count-in before recording starts, and define the beat number on which recording begins.

The transpose (trAN) menu lets you set independent values for the play and record modes of each track over an 88 note range (3C stands for Middle C). Track COPy is used to make transposition permanent before you save to disk.

On to the CLOC menu, where you'll find options allowing you to choose internal, MIDI or Sync operation, and also the Gate mode which records each time you hit a new note on the connected MIDI keyboard - in other words, step-time recording. The Staccato and Legato mode for step-time recording can also be set using the GAtE subroutine to allow you to set the 'on' time of each note separately.

Under the Ctrl menu you'll find the ability to select the recording of MIDI Start and Stop and System Exclusive commands, Note Off transmission at the end of a sequence, the Clock Out and Echo Back functions, and even whether the DJ bleeps or not each time you press a button. The metronome bleep, unfortunately, can't be amplified, which is awkward if you like to play loud while recording your initial track.

We've already mentioned the dEnS function, and the final menu, CHAn, lets you re-channelise a recorded track so that, for instance, information recorded from a DX7 (which can only transmit on MIDI Channel 1) could reappear on Channel 3.


So is the MIDI DJ easy to use as a sequencer? The answer has to be "Yes and No". Recording basic tracks is simplicity itself - go out of the start-up Entr mode by clicking FWD a couple of times, push START to select'1P2r' and you'll find yourself recording Track 2 while you playback Track 1, for instance. The DJ will give you a count in, as set under the bEAt section, and you'll proceed at the tempo and time signature set under the same heading unless you want to change things.

Playing back a pattern is equally straightforward, and loading a new one from disk takes only a few seconds. From the Entr mode, just hit FWD, START, FWD and you'll load the first pattern out of a total of 127 files available on each disk.

However, recording subsequent tracks and combining them does take a bit of thinking about, but probably no more so than on the Yamaha QX7/21 or other two-track sequencers such as the Korg SQD1. While the DJ plays back, a display of the current measure is flashed up and memory available is also indicated to the nearest 1000 notes (a dash '-' indicates less than 50 notes free).

Advanced composition definitely requires some detailed forward planning. If you want to transpose sections, for instance, you have to remember that a decimal point after the final figure indicates a sharp or flat; the new key is shown by a letter such as 'G' and a number to indicate the octave. The track transposed is shown as well, but there's a lot of information which you simply have to keep in your head (such as the fact that a figure '4' in the Sync display means that external sync pulses are divided down from 96ppqn to 24ppqn).

In some senses the MIDI DJ is very powerful - it can be viewed as a 32-track recorder since it offers all 16 MIDI channels on both tracks. You can use the playback channel menu to copy tracks together, thus freeing up new tracks, and there are extensive error indications for exceeding the memory or disk capacity, MIDI communication problems, such esoterica as 'head seek cyclic redundancy checks' (whatever they are!), and so on...

So, sequencing with the DJ can be quite satisfying and complex patterns can be constructed, but a lot of advance planning and copying of tracks and sections of tracks is necessary. In addition to the manual, you'll need a good notebook to keep track of all your sequence information, and the function flowchart supplied is pretty large, so you'll need a flat surface to refer to it. A laminated function reference card like that supplied with the Ensoniq Mirage would have been more manageable.


But it's on-stage that the DJ really comes into its own. If you simply set it to 'record', and play the contents of a Steinberg or Hybrid Arts sequencer file into it from an Atari micro, you can call up the file complete with MIDI channel assignments, controller information and patch changes, then replay it on-stage from the DJ with much more confidence than you could feel if using a micro. Synchronisation to MIDI or non-MIDI drum machines is no problem, and with the Kahler Human Clock and the Bokse Humaniser devices now available, you can even drive your sequencer from a real drummer.

Incidentally, the DJ records System Exclusive information every time it is sent, if required, and with some synthesizers this means every time a new patch is selected. In these cases you'll find your sounds as well as notes recorded as part of a DJ sequence, which is handy if you lose them in between sessions. However, not many synthesizers have this function.

Another problem is that the MIDI DJ has one great omission as a System Exclusive data recorder - it can't send a Data Dump request. Many synths are quite capable of dumping patch information via MIDI, but only if asked to do so by an external unit. Casio's CZ synths fall into this category; there's simply no data dump function on their front panel.

So, as a data filer the MIDI DJ is a little limited, and it is over-optimistic to assume that you can store sounds on it for every synth you're likely to own. It will store sounds from a DX7, but then, the DX7IIFD comes with its own disk drive anyway. Still, the DJ's built-in sequencer functions make it better value for money than Yamaha's standalone MDF-1 MIDI Data Filer, which has the added disadvantage of using those horrible 2.8-inch Quickdisks.


Overall, the MIDI DJ is a very exciting accessory, although one which has made certain compromises to get down to a reasonable price. Some of its four-character displays are cryptic in the extreme, and it'll take you a while before being able to use it (except in the simple, live playback mode) without referring to the manual and flowchart. The sequencer isn't a patch on Roland's MC500, but is reasonably versatile and will allow you to create long and complex pieces (up to 12,000 notes) if you have enough foresight and patience. The live performance possibilities are perhaps the most exciting facet of the machine, while its data filing abilities could make it a bargain if you're currently spending a lot of money on expensive RAM cartridges for a synth which has a System Exclusive Dump command available.

Above all,the MIDI DJ is a fun instrument, with a comprehensive and well-written manual and a very positive approach to life in general. Check it out - it may be the answer to a lot of your musical problems.

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Sound Advice

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Nomad SMC 1.0 SMPTE/MIDI controller

Sound On Sound - Copyright: SOS Publications Ltd.
The contents of this magazine are re-published here with the kind permission of SOS Publications Ltd.


Sound On Sound - May 1987

Gear in this article:

MIDI Disk Recorder > Indus Systems > MIDI DJ

Review by Mark Jenkins

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