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J.L. Cooper MixMate

8-Track Automation System

When you run out of fingers and you find yourself pushing faders up and down with your nose during a mix, then it's time to get a helping hand. Master craftsman David Mellor takes on a new apprentice, the J.L Cooper MixMate.


When you run out of fingers and you find yourself pushing faders up and down with your nose during a mix, then it's time to get a helping hand. Master craftsman David Mellor takes on a new apprentice, the J.L Cooper MixMate.


Mixer automation, when you haven't got it, is the sort of thing you dream about. The trickiest part of any recording session, apart from telling a vain vocalist that he or she isn't quite in tune, is the mix. This is where you can make a track or break it. But how often is it possible to set levels for the track and then leave them alone from the opening fanfare to the closing chorus repeats? Any self-respecting engineer is bound to find sections that need level changes, sometimes very subtle ones, to make the result perfect.

Even on 8-track (and on a 4-track portastudio too) it is nearly always essential to bob the faders up and down quite a lot to achieve that final degree of mix magic. There are ways you can reduce the need for level changes during a mix, but there will always be plenty to keep the engineer busy. Take one example: A song starts with just bass, drums and a synth pad. After an eight bar intro, the vocal starts together with guitar chords, brass stabs and backing harmonies. As an engineer, you have two choices: You can set your peak level to be correct when all the instruments are playing, or you can set peak level at the beginning of the track - but then you will have to back off at the end of the intro, otherwise you'll get a distorted stereo master.

If you take the first option, the attention-grabbing qualities of the intro will be lessened - it's the easy way out. The second option is more difficult to get dead right - the vocal will still need to have the right amount of impact - but it is usually the better way to do it. But even if you get all the necessary fader movements right once when you are rehearsing the mix, you still have to get it right when the stereo tape is rolling - along with all the other fader movements in the mix through to the end. Even if you can do this, your brain is applying 90% of its processing power to your fingers, not to your ears. And it's the ears that make a mix great, not the fingers.

If you are working with a producer (that's the posh name for your friend who sits in on your sessions), then he can do the listening for you. But just think how much more in control you could be if the fader movements were automated. You would only have to get it right once, instead of getting each new fader movement right during mix rehearsals, repeating these movements in every subsequent rehearsal, and then during the mix itself.

I hope the advantages of mixer automation are becoming plain. But there's no use dreaming about it if you can't afford it. With the release of the J.L Cooper MixMate perhaps you can.

Before launching into the review, it's worth spending a moment on examining why automation systems are normally so expensive (allow ten grand or more for a pro system).

The faders on a mixing desk are perhaps the most important components; you could virtually do without any other console component and still make a mix, but not the faders. The function of the fader is to control levels over a range of 100 decibels. It should produce zero distortion and introduce no spurious noises into the signal - clicks etc.

Within its 10OdB range it should have almost infinite resolution. A good fader can do this, and for some types you would have to pay over £50 each for the level of performance required.

To automate faders, there are two options: A fader can be motorised, so that it actually moves up and down under electrical power (as on the Yamaha DMP7); or it can use a VCA (voltage controlled amplifier). Neither option comes cheap. A motorised fader which feels as nice to use as an ordinary one is difficult to manufacture, and therefore expensive. A VCA is also difficult to make if it is to incorporate the very low noise and distortion figures necessary. A professional automation system has to give results audibly as good as the manual method, or it just wouldn't be used. Hence the mega price.

This should put budget automation systems in perspective. There is little possibility of achieving NECAM or MasterMix levels of quality at the sort of price offered here. But even so, I think I may be able to convince you that a tiny box such as the J.L Cooper MixMate can go a long way towards being a quality automation system.

OPERATION MODES



MixMate has three principal modes of operation: 'Normal', in which MixMate functions as a stand-alone unit controlling levels all by itself; 'Plus', where an Atari ST or Apple Macintosh computer may be used to enhance the memory and resolution of MixMate, and provide a graphic display of levels; and 'Lobo' (short for 'lobotomy' perhaps?), where the automation and synchronisation functions of MixMate are switched off, and the unit functions as a box of MIDI controllable VCAs, perhaps under sequencer control.

Let's start by examining the Normal mode of operation. Since MixMate is an eight channel device, it has eight input phono sockets and eight output sockets. You would plug the outputs of your 8-track tape machine into MixMate, and plug MixMate's outputs into the channels, or tape returns, of your mixer. The faders on the mixer would all be set to 0dB and MixMate would take complete charge over levels. You could perhaps plug MixMate into the channel insert points, it's up to you and your set-up which way you do it.

The essential point to remember is that the mixer's faders would not be moved at all, unless you had some particular reason for doing so. Mixing operations now proceed using the MixMate faders.

Synchronisation to tape is via either J.L Cooper's own 'smart' FSK tone (see sidebar) or conventional SMPTE or EBU timecode, which the unit reads and generates. During mix operations, all fader movements are logged against timecode, and so relate to specific points on the tape. If you move a fader at bar 21, say, then MixMate will replicate this move every subsequent time you pass bar 21, until you change your mind. Since MixMate uses VCAs and not moving faders, the faders themselves do not actually change position, rather the VCAs inside MixMate make the appropriate gain changes as if they had.

SETTING UP A MIX



This is how matters proceed from when you decide to finish overdubbing and start to mix: MixMate has four editing modes, in which fader movements are tried out, written into memory, altered, or simply read. The first part of the process is to establish roughly where the faders will be throughout the song. Do this as you would in a conventional mix situation. This is Manual mode.

In Write mode, any changes you make to fader levels will be written into memory. Write mode can be enabled on any channel, or all channels simultaneously if you wish. There is no restriction in the number of faders you can move at anytime.

In Read mode, you play back the multitrack tape and MixMate makes all the gain changes you have entered. This is a good time to mention that since the faders do not move themselves (unless you move them), it is often going to be the case that the fader position does not correspond to the current level of the VCA. For instance, the physical fader could be at -10dB and the VCA could be at -20dB. Fortunately, there is a 'null' LED indicator above each fader, which indicates when the two levels are the same. If the null LED isn't on, then you don't know which is lower and which higher, but you can tell if they are identical. This will come in handy in a moment.

It is highly unlikely that you got all the level changes right first time. If you could do that every time you wouldn't need automation in the first place! Hence Update mode...

Suppose you have a track which needs to move up and down in level a lot, probably the vocal track. You make these level changes in Write mode, and they are largely OK. If one section of the vocal, Verse 2 perhaps, wasn't good, then you redo Verse 2 in Write mode. That makes the level changes OK.

Suppose then that later on in the mixing procedure you decide that the vocal isn't loud enough all the way through. Do you have to go through the process of re-entering all those level changes a couple of dB higher?

Fortunately not. To update settings, you set the fader to a central position and enter the Update mode. Now, while the tape is running, any movements you make will be superimposed on your original settings. Note that you are not indicating absolute levels with the fader in Update mode, but relative level changes. This can be done as much as necessary on each track to get the mix absolutely right. Even on 'easy' 8-track mixes, MixMate can do more than fingers could ever remember. Even though the process of writing and updating can seem long-winded, you only have to get each move correct once - MixMate gets it right every time thereafter. Now you have the chance to sit back and listen to the mix, and concentrate on how it sounds, rather than having to do two things at once and not really succeed at either.

VISION ON



One problem with the method I have described above occurs when you alter just a section of the mix in Write mode. This will probably happen often during the course of a mix. What you are actually doing is 'punching in' a new segment of mix, just as you would a guitar solo on the multitrack tape. Suppose you are coming up to the section where you want to punch in; you are in Write mode with no channels enabled yet. The section approaches and you switch the appropriate track to be enabled. You grasp the fader and start to move it...

Unfortunately, the fader position didn't correspond to the VCA position as you approached the drop-in. When you moved the fader, the VCA gain changed very suddenly to meet the actual fader position (as it must in Write mode) and you didn't achieve anything like the effect you wanted. Ten times worse in fact.

This is what the null LED is for. If you had made sure the null LED was on before you switched into Enable, then the physical fader would have been in the right position to make the correct change. Not only that, but you have to know what the correct null position will be after the punch-in and return to it before you de-select the Enable mode, or the level will be incorrect until the next fader move, when it will correct itself.

This type of operation is made easier if you use MixMate's Plus option, where the unit is connected to an Atari ST or Macintosh computer. This gives you a display of the physical and the VCA fader positions on screen, so you are better placed to know exactly what is going on at any point in the mix. The screen also gives a timecode reading in the top right corner, which makes a handy reference for different positions in the song.

Update mode is particularly good here, because not only do you see the physical and VCA fader positions depicted on-screen, you are also shown the Update Reference. This corresponds to the position of the fader that will have no effect on gain changes as you update a mix. Above this position will add gain, below will subtract it.

MUTES



Another aspect of mixer automation is the control of channel muting. Muting is a second level of operation over and above fader automation. It is possible to programme a complete series of fader moves on a channel, then decide that the mix would be better without it, and then change your mind and still have the fader movements intact.

It is also good practice to mute any channel at times when it isn't contributing to the mix. Muting reduces tape noise and also gets rid of any rubbish that might be on the tape so that actual mixing is made easier.

The Enable buttons on each channel also act, by pressing a Shift key, as the mute controllers. Run the tape and channels can be muted and unmuted as you wish. As in the case of fader movements, mutes can be edited. It would be a bit long-winded to explain exactly how it's done. Suffice to say that you can remove mutes if necessary and alter the off and on times at will (and a little practice may make this the less than obvious procedure it seems when you first start to use MixMate).

MIDI MIXING



MixMate may seem like mixer automation cut down to a more appropriate size for the home or small studio, but there is more to it than that, and MixMate can prove useful in situations other than the conventional mixing of multitrack tape to stereo tape.

Sequenced MIDI systems offer a viable alternative to multitrack tape-based systems, but there is no less of a need to automate the final mix. I could go so far as to say that it's more essential to have an easy-to-use automation system in this case.

In a multitrack set-up, one of the best ways of reducing the complexities of a mix is to make sure that levels are accurately controlled as they are going down on tape. That means using a compressor. If you record tracks one after another, then you can use the same compressor on each track. The result is a multitrack master with consistent levels on each track which need adjustment only for artistic, not corrective, reasons.

A MIDI system needs this control just as much, but because all the instruments are playing at the same time, you would need one compressor per instrument to achieve the required result. A bit expensive that - and mixing everything together before putting it through a compressor doesn't achieve the same result. To make the necessary level changes by hand, or by programming them into the sequence, would be a pain. MixMate can help.

BRAIN REMOVAL



I mentioned Lobo mode earlier on. I think that J.L Cooper Electronics have something against using MixMate in this way. As it says in the manual: 'If you only plan on using MixMate as a brainless box of MIDI-controllable VCAs... Lobo modes will deal with your kind.'!! But even if MixMate's designers don't like it, the Lobo function has hidden promise - the promise of expansion to 16-track operation (or even up to 512-track operation, if your sequencer and your wallet can handle it!).

Lobo basically means that only the faders and VCAs of MixMate (and the synchronisation functions, incidentally) do anything. It doesn't store any mix data either in itself or in the computer. (Lobo doesn't need the computer). The faders are used to generate MIDI data, which can be sequenced like any other MIDI data. The VCAs are then controlled by this MIDI data. Let's go into a little more detail...

Lobo mode 1 outputs fader position as MIDI controller data, like that generated by a synthesizer's pitch or modulation wheel. Lobo mode 2 outputs fader position as MIDI note data, with each fader assigned a note number, the velocity of the note corresponding to the fader level. Since MixMate can be set to eight different sets of controller numbers, or eight different ranges of notes, in theory it ought to be possible to run 16 MixMates on one MIDI channel. I haven't tried it yet!

What you lose by doing it this way is the task-specific programmability of a mixer automation system. Mixmate, used in its Normal mode of operation, is precisely tailored to the task of recording mix data. A conventional MIDI sequencer is tailored to the recording of notes played on a keyboard. This means that editing a sequence of fader moves is likely to be more tricky than doing it the conventional way. Sudden level jumps are likely to occur unless you are very careful in your use of the null LEDs.

BUT...



This is my conclusion on MixMate: I like it. (That'll fox all those people who look for the conclusion at the end of the review!) But, as mixer automation goes, it is an inexpensive device and so there must be some drop-offs somewhere.

Operationally, one problem is the lack of any 'snapshot' ability. I would have been greatly pleased if I could have set levels for one part of a song, set levels for another, and then stored these as 'scenes' and programmed scene changes. Since most pieces of music come in repeating sections, this would make life a lot easier. Mute editing in particular would be a lot better.

Another operational problem is in the storage of mixes - alleviated somewhat in the Plus version. As a stand-alone unit, without computer, MixMate only remembers its current data. There is no way of going back to any previous attempt at a mix unless you do it again yourself. Mix data may be dumped via System Exclusive but, depending on your MIDI system, this may or may not be a viable procedure for use while rehearsing a mix.

The Plus version of MixMate is better because any number of mixes can be stored on disk via a Mac or ST computer. There is also an auto-archiving function which will store any new data to disk whenever MixMate is idle for a moment. There are two levels of archiving, so you can go back to your last-but-one mix at any time. I feel it might have been better to adopt a system of storing, say, four mixes and rotating them by automatically replacing the oldest mix with the most recent. If any mix seemed to have potential, it could then be 'locked' and kept safe (as in Audio Kinetics' professional MasterMix system). MixMate seems to assume that the operator's efforts will always continue to improve a mix. This is often not the case.

MIXMATE SPECIFICATION

VCA
Type: dbx 2155A
Typical Signal-to-Noise Ratio: 86dB
Typical Total Harmonic Distortion plus noise: 0.022% (Level and Frequency not specified)
Attenuation: -81dB (Frequency not specified)
Channel Crosstalk: —90dB (Frequency not specified)

MEMORY
Normal Mode: 4000 events
Plus Option: 40,000 events

FADER RESOLUTION
Normal Mode: 64 steps
Plus Option: 126 steps

TIMING RESOLUTION
SMPTE: +/-½ Frame
FSK: nearest Clock
Mute Response Time: 20ms
Tape Sync speed variation: +/-10%

Performance-wise, if I listen hard I can just convince myself that I can hear the difference between the input to MixMate and the output after going through a VCA, but it's a very close thing. MixMate does generate some noise which does not reduce with reducing fader level, as would happen with a conventional mixer. My feelings on this are: 1) that it's pretty low level noise anyway; and 2) that automation will help the user to minimise tape noise from the multitrack tape.

Zipper noise (see 'MIDI Automation Systems - How Good Are They?' by Graham Hinton in SOS February 1988 for an explanation) is audibly non-existent, even on pure tone, but the steps taken to effect this make the faders slightly, but not inconveniently, slow to respond.

The resolution of MixMate is a little on the coarse side. I calculated the minimum level change to be around 0.5dB using the Plus option, increasing to a little over 1 dB when using MixMate as a stand-alone unit (it appears to vary over the fader's range). The maximum input level before clipping was +14dBu, which is OK for use with —10dBu operating levels. With standard operating levels it would need to be borne in mind, but should not be a problem in normal use. Fader calibration was not good. An indicated -10 gave a measured -5dB, an indicated -30 gave -40dB.

Having made a few criticisms it is necessary to say again that MixMate is a tiny fraction of the cost of fully pro mixer automation systems and we can't expect it to have quite the same level of performance. But if you don't have any form of automation at the moment, MixMate will improve your mixes and it will make them easier.

Price £995 (£200 extra for Plus option).

Contact Evenlode Soundworks, (Contact Details).

SYNCHRONISING MIXMATE

The J.L Cooper MixMate offers several synchronisation options: SMPTE/EBU timecode; MIDI Time Code (MTC); 'Smart' FSK; MIDI Sync.

• MixMate reads and writes SMPTE/EBU timecode in all four common formats. Timecode values are displayed on screen (Plus option only).

• MixMate can send out MIDI Time Code while reading SMPTE from tape.

• 'Smart' FSK is a sync pulse which represents MIDI Sync and Song Pointers and can be recorded on tape. This is the same 'smart' FSK as used by the J.L Cooper PPS1. MixMate will recognise the location in a song when the tape is started from any point and send out MIDI Sync and Song Pointer information to connected MIDI devices.

• Mixmate will also lock to MIDI Sync and Song Pointers when driven by a MIDI sequencer.


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My Ideal Sequencer

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Sound Designer Universal


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 - Oct 1988

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Review by David Mellor

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