David Mellor, Assistant Sound Engineer at the Royal Opera House, Covent Garden gives us his views on the latest in automatic synchronisation by reviewing the Audio Kinetics MasterMix and Q-lock systems.

There's an old story circulating in the audio industry which relates that when EMI first considered acquiring an 8-track recorder for their Abbey Road studios, they planned to spend a six month trial period finding out whether it would be possible for one engineer to cope with all the faders this would involve! Apparently there was a popular band of the time who fortunately managed to persuade the management to put the machine into Studio 2 straightaway. (I think they were called the 'Beatles', or something like that!)

It all seems so simple now, what with eight fingers for the channel faders and two for the stereo masters. Things are not so easy however, when there are 16 tracks to play with, and it's not uncommon for the members of the group, plus the odd roadie or hanger-on each to have responsibility for a couple of faders to help the engineer deal with a tricky mix. The problem is compounded when more tracks are available, and with producers demanding two or three 24-track machines to be locked together, then it is perhaps fortunate that the Semiconductor Scientists and Masters of the Microprocessor have been busy building clever machines to do all the difficult bits and leave the engineer free to apply his creative brain to the task in hand: making music.

Nowadays, in any 'quality' studio, it's more or less standard to have not only mixing console automation but also synchronisation facilities to link various audio and video machines.

Console automation makes it possible, during the mixdown of a multitrack master, for the engineer to only have to move any fader once for a specific purpose, no matter how many times the track is played through before committing to stereo - and this could be anything from several dozen passes upwards.

Mastering the MasterMix

To illustrate the uses and capabilities of automation and machine synchronisation, let's take two products from one of the world's major designers, Audio Kinetics.

The MasterMix is a highly refined automation system, and unlike earlier designs has been developed so that it interferes with the mixing process to a very minimal extent. In other words, the engineer is able to push faders up and down, try out ideas and indeed take the odd risk, confident in the knowledge that should he like what he hears, the computer has recorded his fader movements and can repeat everything he has done faithfully.

As hardware, MasterMix consists of a central computer, which comes in a 2-U rack-mounted unit with an integral floppy disc drive, a console interface (without controls), a control unit which would be positioned on the mixing console and a set of VCA faders which replace the standard audio faders of the console. Some mixers are supplied 'automation ready' which means that they already have VCA faders which could be interfaced to the MasterMix system.

Pick 'n' Mix

Taking the faders first, 'VCA' means the same as it does in synthesiser terminology: Voltage Controlled Amplifier, except for the fact that in this case the VCA is an ultra-low distortion, low noise high bandwidth device. VCAs are used because the level of the audio in each channel needs to be controlled from two sources, the fader itself and the computer. In addition to the normal fader control there are a number of buttons which talk directly to the computer, telling it whether to write data into the computer memory, to update (or rewrite) data which is already stored, to read data coming from the computer, or to isolate the fader and return to purely manual control (for old timers!).

The unit is simple to use, yet comprehensive, and all the main functions seem to lie under your fingertips while still managing to remain uncomplicated.

Unlike some early automation systems, which stored actual mix data on two spare tracks of the multitrack tape, MasterMix is timecode based, using up only one track of the multitrack and storing data in the computer memory. Before starting a mix therefore, it's necessary to stripe the multitrack with timecode (which the unit provides) if this hasn't already been done. Once this chore is out of the way, you can start the mix.

"The unit is simple to use, yet comprehensive, and all the main functions seem to lie under your fingertips while still managing to remain uncomplicated."

Firstly a mix is made without using automation. This sets rough levels from which to make changes and tweaks. Two buttons are then pressed which tell the computer that a complete new mix has been started, from then on it is not necessary for the engineers' hands to leave his faders! There are four memories available in the MasterMix system, designated A, B, C and D, each of which can store data for an entire pass through the song. On the first pass, any faders movements will be recorded into memory A together with positions of any faders which remained static. On subsequent passes, any fader needing adjustment will be switched by the engineer into Write mode by way of the switch on the fader, the complete state of the mix plus any new level changes being automatically recorded into the next available memory. This can be done four times (obviously), before all memories are full, then the computer will cycle back to memory A and overwrite data previously recorded there.

As the mix becomes more finely tuned it will become necessary to compare one mix with another to see whether that 2dB up on the nose flute and 3dB down on the sousaphone really improved matters at all. This can be done simply by pressing the relevant memory button A, B, C or D. Any mix which 'has something' can be selected to safe mode, whereby new mixes will overwrite the oldest memory, but leave intact the one you intend to keep.

One feature of MasterMix which is not universal to automation systems is what might be called the 'All the way through' system. Although it's totally transparent to the engineer (which means he doesn't have to do anything to activate it) it is a great saver in terms of studio time. For example, suppose you have got to the point where the mix seems fine, apart from the bass being too quiet (it's a reggae session!), you can simply up the level by a few dB, play the tape for a few seconds, and the computer will regard this as applying to the whole mix, all the way through. How to save five minutes of studio time at £75 an hour in one easy lesson!

Mixes can be merged together. Perhaps one mix has a good verse and another a good chorus, and these can be simply spliced together by the computer. All that's needed is two presses of a button. When the mix is finally complete and in the computer, you can send the band home, take out the floppy disc, replace it with the disc containing the version you have secretly been working on overnight with the extra loud bass, press play on the multitrack, record on the stereo and that's another satisfying mix finished!

Q-Lock

'Another 24-tracks please,' said the producer in the post-production session, 'and let's get the video finished by opening time.'

Two 24-track machines synchronised to a U-matic video cassette player, not to mention that 2-track in the corner with crowd effects, or the cartridge player for the door slam! Set-ups like this are commonplace these days, although it still seems a bit like science fiction for a selection of audio and video machines to click into fast wind, whirr, stop, then play together in exact sync all at the push of a single button.

Even in 1986, synchronisation is not technically easy and I think it's fair to say that it is only now beginning to come of age. Q-lock was introduced by Audio Kinetics to a waiting world in 1978 and has been under continual development since then, culminating in the release this year of the Eclipse Editor, a very versatile machine control system which adapts to the particular ways in which the engineer wants to use.

The basic Q-lock 4.10A consists of a 3U rack mounting computer, together with the Alpha control unit. The mainframe consists of machine interfaces and time code readers for each of four machines, time code generator and a central processor. There are, in addition, event relays for the automated start-up of cartridge players, turntables and so on. The Alpha controller is a free standing box some 30cm by 20cm, or is available ready to flush mount into the mixing console. This is confusingly called the Beta version.

Like console automation machines, synchronisers observe time code which must be recorded on a spare track of the multitrack, an audio track on the video tape or cassette, or a centre track on a stereo tape recorder. Time code is confusing stuff and comes in different brands known as SMPTE, EBU, SMPTE drop-frame and film. There's a lot of loose terminology flying around and a lot of people will refer to time code simply as SMPTE. SMPTE as it happens, is excellent stuff if you happen to be American, Canadian, Japanese and South Korean, but in this country we use the European standard EBU time code for reasons of TV standards, unless we happen to be recording digital audio on a Sony 1600 series system, but that's a different story. Lecture over!

"Another 24-tracks please," said the producer in the post-production session, "and let's get the video finished by opening time."

Timecode is a reference signal which contains information on hours, minutes, seconds and frames (¹/₂₅th of a second) so that every point on each tape or cassette in use can have its own unique reference. Note that for synchronised playback, the time reference will not necessarily be the same on each tape. The most basic synchroniser will therefore have to be able to cope with offsets in timecode.

Q-lock 4.10 with the Alpha controller will synchronise up to three audio or video machines. Four can be connected to the system but only three can be selected to be on line at any time. Transport control is provided for each machine so that there's no need to have four remotes cluttering up the mixer and getting in the way of the coffee mugs and ashtrays. Autolocate functions are also provided which means that you can enter a timecode value for any or all of the machines and they can find that spot on the tape automatically (there are ten memories so it's simple to go to a verse or chorus or whatever). Automatic drop-ins can be processed too, this is done by running the tape and pressing the entry button so the machine can memorise the in and out points, or it can be done by numerically entering timecode values. The benefits of automated drop-ins should be obvious to any engineer who has performed a drop-in perfectly 27 times while the singer fluffs his words, and then is so amazed when the singer gets it right on the 28th that he forgets to drop out and erases the entire next line.

It is perhaps not immediately obvious, but programming drop-ins, setting offsets, bringing picture and sound perfectly into line; these all require a lot of button pushing. If you consider an application such as dialogue replacement, where an actor has to redo lines that were spoilt in the original recording by something like outside noise, and he has to repeat these lines until they sync exactly into the picture, then it's comforting to know that the team at Audio Kinetics have been busying themselves writing software for applications like these so that it can all be done at the touch of a single key. If you have a specific synchronisation application, the chances are that there's a Q-lock program for it already written.

The Eclipse Editor takes the Q-lock system a stage further. This device replaces the Alpha controller in the Q-lock 4.10 system, or will interface with a future family of synchronisers which Audio Kinetics promise will be able to handle up to 32 machines. One immediately apparent advantage of Eclipse is that instead of LED timecode readouts there is a large electroluminescent display which shows about 20 lines of information at a time and provides you with everything you need to know that is going on in the system. This display changes according to the particular mode of operation the Eclipse is in, and there are menus available for setting up routines and parameters. (If you get stuck, call for help; there are 'help' pages for several functions and more are being written into the software all the time.)

I mentioned earlier that it's possible to have software written for the Alpha controller for specific applications. The Eclipse goes further than this; you effectively write your own! Eclipse has twelve 'Q-keys' and each Q-key can record a series of button presses (up to 256 in fact, which ought to be adequate!), so whatever boring repetitive task you have, such as setting up the machines in the morning, bringing them on line and setting offsets can all be done by Eclipse while you do something more useful. (How about a coffee?)

"The intelligence of Eclipse is such that it can actually learn as it is going the characteristics of each machine under its control."

The intelligence of Eclipse is such that it can actually learn the characteristics of each machine under its control as it goes. As you can appreciate, a reel of 2" tape hurtling around in fast wind possesses considerable momentum, and if the stop button is pressed while the tape is travelling at full speed then several metres of tape will have been wound before the machine comes to a halt. From the first operation of the day, Eclipse measures the ballistics of each machine and after three or four wind/stop/play routines, it has acquired sufficient knowledge of the reaction times of the transport mechanism to operate it always in the most efficient manner. (Although it would be impossible to store this in memory parameters for a given machine as this would not take into account day to day variations in transport characteristics.)

Although the Eclipse controller is more complex in its operation than MasterMix, this is simply because there are more functions to be performed. Once the system is learned and a few Q-keys programmed, it should be possible for the engineer to treat it like a tape-op. Say what you want and it will happen, except that if you give Eclipse precise instructions, it will carry them out to sub-millisecond accuracy every time without error. It won't make the coffee though - yet.

It will come as no surprise that state-of-the-art systems such as MasterMix and Q-lock are not cheap, but considering the facilities they offer to the professional studio they're good value for their price. There has been, however, until very recently, very little in the way of automation and synchronisation for the smaller studio setup.

How quickly things change, for hot on the heels of the new Fostex synchroniser we have the forthcoming Pacer 2-machine synchroniser from Audio Kinetics which will have all the accuracy, (but less of the speed and functions) of the big boys' system. Also new on the market from Akai is the MPX820 MIDI mixer which crams a remarkable amount of automation into a rack mountable 8-channel unit.

If the thought of all this computerisation of the studio worries you at all, then just remember that at the end of the day, it's purpose is to make the engineers' life easier by relieving him of mechanical functions that are better suited to microprocessors, and free him to concentrate on the music, to use his skill and judgement and, most of all, his ears.

My thanks to David Neal of Audio Kinetics for providing demonstration facilities for MasterMix and Q-lock.

Further information is available from: Audio Kinetics Ltd, (Contact Details).

The Audio Kinetics MasterMix costs £10-18,000 depending on the console, and the Q-lock just under £8,000 plus VAT. The Eclipse Q-Lock costs £12,600 plus VAT.