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Programmable Automation Computer

New writer Roger Jackson reveals how this mid-priced programmable automation computer can be used to automate mixes on any manufacturer's mixing desk.

Dear Mum, how are you? Today I computerised my mixing desk for under £1,000...

Yes, it's something to write home about! MIDI is getting more and more diverse by the day, and here from a new Danish company, Twister Engineering, is a machine with professional noise and distortion spec which enables you to record the mutes and fader movements of your mix on any MIDI sequencer.


Twister is an eight channel fader and mute box all under MIDI control. That is, eight inputs and eight outputs. You connect it into the insert points of your mixer, plug the MIDI Ins and Outs into your sequencer, and you have instant computer control of your mixes. We shall discuss applications later, but first let's look at the machine itself.

Twister (fortunately, the name seems to be the only naff thing about it) is supplied in a standard 19-inch 1U rack-mounting case. The user interface, or front panel, has 18 very nice buttons, which have a very positive action and make you want to press them, rather like that polythene packing stuff with bubbles you just have to pop. But I digress.

All data input is via a continuous rotary dial on the front panel and 26 LEDs tell you, surprisingly clearly, what you are doing (so you can tell anyone else when they ask!). A two digit display and an LED meter provide visual feedback.

The back panel sports MIDI In, Out and Thru, eight stereo in/out quarter-inch jack sockets (tip/in, ring/out, sleeve/ground) and a 25-pin 'D' connector SCSI port, of which more later.

The front panel is clearly laid out in four sections. From the left, we have the Memory section with its two digit LED display and three buttons relating to the memorised functions (MIDI channel in/out, program memories and level memories), store, recall and up/down buttons. Next is the Function section which enables you to switch between mute and fader functions and to select which channels or groups you are working on. The centre panel governs Channel Select with eight buttons and eight LEDs available to (yes!) select channels, individually or in groups, for muting or fading. Finally, we have the Meter section. Here you can choose to meter the input or output of each channel, or the 'fader level' as set by the continuous wheel on the far right, working at fine, medium or coarse resolution.


Once I had established this much, the rest was pretty plain sailing. Ignoring the computer link-up for the moment, I inserted the eight Twister channels across the first eight input channels of my Seck 18-8-2 mixer, set the tape of my latest opus rolling, and commenced with a few mutes. These are easily achieved by selecting 'Mutes' and 'Channels' in the Functions section and then pressing the Channel Select button for the channel you want to mute. Likewise, selecting 'Levels' and pressing the Channel Select button makes the continuous wheel active for that channel.

These functions - mute and fade - can also be applied to all channels simultaneously, or to any group you care to select. Group selection is done by calling up 'Set Group' from the Functions section and then pressing the Channel Select buttons corresponding to the channels you wish to be included in that group. Pressing 'Set Group' again stores that group in memory, leaving you free to select another grouping.

Any configuration of 'fader positions', mutes and groups may be stored as any of 99 programs, or snapshots, which can be recalled in any order, giving you instant mix changes. There is also a handy 'Memory 00' button for returning you immediately to a preset home base, whether it be to the 'all muted' or 'all faders fully on' position - effectively a bypass facility. Storage of these programs is by the familiar method of pressing the up/down buttons till you get to the memory location you want, then pressing 'Store'. I'm sorry if this is reading a bit simplistically, but it is simple. You get the uncanny feeling when using Twister that a psychologist has been through it all before you and knows exactly what button you are likely to press next.


Twister connects to your MIDI sequencer in the same way as any MIDI keyboard. Selecting mutes sends note-on info, to identify the channel with high velocity to mute and low to unmute, so you could operate these from a velocity-sensitive keyboard if you wanted. The first eight channels correspond to notes C1 to G1. Fader information is sent as MIDI controller data, and a value between 1 and 127, controllers 00-07 being the first eight.

MIDI maniacs amongst you will have sussed already that controller 01 is our trusty modulation wheel and, therefore, you can operate that from the keyboard too. In fact, if you have a master keyboard or anything on which you can reconfigure MIDI controllers, you can do everything remotely. I arranged the four sliders on my Yamaha KX88 to become mixer faders for the first four channels, for example. The aforementioned memorised programs of fader, mute and group configurations are stored, logically enough, as MIDI program changes and appear in your sequencer memory as such.


So much for theory, but how does it work in practice? Funny, but even with all the technological wonders we have seen over the last few years, I still found it quite hard to believe that Twister was actually going to work; that the thing would mix itself, using the same sequencer that had recorded the song in the first place. It seemed a bit cannibalistic somehow. So does it actually work? Let's see...

Recording on track 24 of the Steinberg Pro-24 sequencer I had synched to tape, I ran through the piece first time doing mutes. This was a brilliant clean-up operation. Now there is no need to have any tracks running empty, adding their hiss to your master when they don't have any music recorded on them. Changing to record on track 23, Twister takes in the information played back on 24 and adds the fades, so we are left with the combined fades and mutes mix on track 23.

Now supposing we were not completely happy with just one of the fader changes in that take? Easy, just go for another pass, listening to track 23 while recording on 24, and when you get to that rogue fade, simply re-do it correctly. Twister sends updated information on just that fade or mute as soon as you touch the controls, while keeping the rest of the mix the same. If you get it wrong again, you can roll back and drop in. You don't have to execute your mutes and fades separately, of course, any of the functions can be performed in any order just as you would do on your mixing desk.

Okay, Roger, what do you reckon so far?

Well, I am completely knocked out by the simplicity of operation of what are, after all, some very complicated manoeuvres. This is how machines should be designed: the machine does all the hard work, leaving the operator free to concentrate on the mix.

It is quite alright, for instance, to wind the tape back and jump in at any point: Twister will pick up the mix as it is at that point, rather than as it was when you stopped. It does this by sending out snapshots of the status of the mix every two seconds as a bundle of system exclusive data.

Another non-obvious problem has a similarly ingenious solution: What happens when one member of a group gets to the top of the fader range and you are still trying to increase level on that group? If it were to continue, the relative levels that you had so carefully set up within the group would be changed. So Twister stops any further increase, and flashes the 'Levels' LED to tell you that you can't go any further. Similarly, if you try to perform a fader function on a channel which is currently muted, then the 'Mutes' LED flashes as a warning, although this doesn't occur when you are doing the same to a group. A strange inconsistency in an extremely consistent machine.


To summarise then. Twister is a MIDI-based mix automation box. Mutes and fades can be performed on individual channels, or on groups, and stored as MIDI data on a MIDI sequencer. A mix can be built up bit-by-bit, bouncing between two tracks of the sequencer. The SCSI (Small Computer Systems Interface) port which I mentioned at the beginning is for connecting additional Twister units together to build up a bigger automation system; the initial unit gives you eight channels, but can be easily extended to 16, 24, 32 or 64.

Incidentally, you may want to record your mix information differently, spreading it across several tracks of the sequencer and building it up like that. In this case, however, Twister would be 'listening to' each of the channels simultaneously, so you should turn off system exclusive to prevent the snapshots from conflicting.


Let's look now at some applications. We have already seen how your mixes can be MIDI-fied and stored on your sequencer, as part of the song if you choose. But I reckon Twister is going to be very handy for all sorts of things.

For instance, it is really great for doing dub mixes where, in addition to including or excluding different parts, I found it great for controlling the effects sends on any channel, to catch the ends of vocal lines in repeats, for example, or for letting every fourth snare beat through to a massive reverb.

One very smart use I came across was for gating the reverb returns. Switch a mute for every snare beat and then quantise it (remember that mutes are note-on info), and then delay it by exactly the time you want the reverb to last. Stick it over the reverb return and you have got the cleanest gated snare y'ever did hear. Copy the track and change the delay time, pan it across the other side of the effect return and you have got a sound which whips across the stereo image with every snare beat.

If you are one of those people who tries to cram 32 tracks worth of music onto eight tracks, you can let Twister handle that unexpected sackbut entry which bursts into track four just after the pin drop, and leave your hands free to check out any EQ changes which may improve matters, instead of having to worry about what forgotten part is about to rip the cones out of your speakers. Likewise when you are trying to decide which particular combination of your 20 vocal tracks is going to wow the Eurovision audience most, you can listen to a variety of possible bounces without all your concentration being taken up with the complicated sequence of switches and fades.

You could have all channels muted before the beginning of your song and un-mute them track by track as they appear, so that your digital master has no hiss before the music starts.

Live, you could use Twister to handle those irritating level differences which occur between different patches on your synth, or, if you are able to reconfigure the MIDI controllers as mentioned earlier, then you could remotely mix your slave instruments, which can now be racked neatly out of the way of your flailing limbs.

These are just a few applications which sprang very rapidly to mind as I got more and more into Twister, and I'm sure that everyone will think of their own special uses. Certainly I very easily used up 16 channels even on an 8-track system.


Linking units together via the 25-pin SCSI port on the rear panel does several things at once. First of all, the second Twister unit sends its mute messages on the next eight MIDI note numbers (G#1 to D#2) and its fader info on the next eight MIDI controllers thus removing the possible confusion of the two units trying to use the same data for different channels. But more than that, they become one large machine, so commands addressed to 'all' do, in fact, address all 16 channels, and it is possible to subgroup across separate units, bringing channels from each of them under the same group control. You can set the front panel control wheel on each unit to operate independently on different channels, or have them work together, say one at coarse resolution and the other at fine.


In conclusion then, I have to give Twister very high marks indeed. It is beautifully constructed, the ergonomic design of the software is exemplary and the sound quality is stunning - it uses the same VCAs as SSL mixing desks and claims a signal-to-noise figure of -95dB, although the units I tested were better than that.

There is nothing like it currently available - an affordable tool for the (serious) home recordist, but an absolute must for the professional studio who can now offer computer mixing facilities for a previously unheard-of price. Especially as Twister will soon be available as an internal retrofit to any mixing desk, and controllable from an Atari ST computer with a screen display of the full logical mixer. An optional remote eight channel fader and mute box is also on the way.

Other exciting goodies on the drawing board include analysis of the analogue input and output to control the processing, ie. gating, limiting and compression. These will be stored in the 99 program memories already included in the hardware.

Twister is going to be BIG!!! Can I have one please?

Price £995 inc VAT.

Available from The Synthesizer Company Ltd, (Contact Details).

Also featuring gear in this article

Previous Article in this issue

MIDI Matters

Next article in this issue

Elka ER33

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 - Aug 1987

Feature by Roger Jackson

Previous article in this issue:

> MIDI Matters

Next article in this issue:

> Elka ER33

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