Audio Kinetics Pacer Synchroniser
The big boys of the synchronising world have sat back and observed the appearance of budget systems from Fostex and SMPL over the past six months. Now Audio Kinetics dip their not in considerable toe in the water with the launch of their own low-cost chase synchroniser system, the Pacer. David Mellor checks it out.
There are already low-cost synchroniser systems available from Fostex and SMPL, but with the release of the Pacer, big boys of the synchronisation world Audio Kinetics have dropped their not inconsiderable toe in the water with a system that sells for less than £2000 plus VAT. David Mellor investigates.
The Pacer is a two-machine chase synchroniser contained within a neat 1U 19-inch rack-mounting box which includes a multi-standard timecode generator and interfaces for several types of machine. As an extra at around half a thou you can add the Pacer Pad - a smallish box which acts as a remote for the main unit and as a controller for the slave machine. The Pad also incorporates a timecode display which can show where the machines are, timecode offsets, record in and out points etc.
The concept of the Pacer differs from that of the Fostex system (reviewed May 86 issue) in that it is intended to be a complete system for two machines, master and slave. It is not expandable in the same way as the Fostex, but from their experience with Q-Lock over the past eight years or so, one might expect Audio Kinetics to have a few tricks up their sleeve that the opposition have not got around to yet. The proof of the pudding is in the synchronising!
I probably have a bit of dog in my ancestry because every time I meet a new piece of equipment, the first thing I do is to go nosing round the back! (I could tell you tales about the time I looked at the rear of a certain new state-of-the-art (clue!) mixer and found a bit of Veroboard hanging from its innards, but I am sure the B*C had a good reason for it!)
The Pacer is as neat at the back as it is at the front, the rundown being as follows: IEC mains inlet and switch. I for one prefer rack-mounting equipment to have the mains switch at the back out of the way. It has to be there to comply with regulations on equipment of over a certain wattage, but I am convinced that one mains switch per rack is enough!
Next comes the Pacer Pad inlet, a 15-way D-type connector. You may if you wish connect a suitably programmed computer to this terminal instead of the Pad. Audio Kinetics supply the protocol, so you could interface it to your PC - when it's not doing the accounts. The slave machine is connected via a 25-way D-type, which takes care of the transport functions, and a 3-pin XLR for incoming timecode. There is also a small screwdriver-operated rotary switch which is set according to the make and the model of your slave machine. There are sixteen positions on this switch and internal jumpers can extend the range which can be accommodated even further.
Slave interfaces are already available for the Tascam range of tape recorders (excluding the model 38, which cannot be interfaced to a synchroniser, except perhaps by internal modification), the Otari range, and Studer 810. Those being planned, which could be ready by the time you read this report, include Fostex, Studer A80 and A800, and the Revox PR99 MkII. Audio Kinetics are also aware that the prospective Pacer purchaser could be someone who picked up a multitrack such as Ampex or 3M secondhand, and interfaces for these are in the pipeline too. The chances are that if your machine is capable of being controlled by a synchroniser, and if you bend Audio Kinetics' ear, then an interface will become available.
The master connector is a 9-way D-type which accepts tach and direction information, and an XLR for timecode. The Pacer is capable of learning from the master machine its tach rate and direction indications, so all that is needed is the correct interconnecting cable. Master and slave cables (which I included in the £2000 price guide) seem rather pricey at £95 and £135 respectively, so you may prefer to make a saving and run them up yourself.
Adjacent to the rear panel's master timecode input is the timecode generator output. Output level can be varied from zero to nearly +18dBu, balanced - which should be an adequate range! Both master and slave timecode inputs, by the way, will accept a level from -30dBu to +10dBu balanced, without requiring adjustment - which is similarly adequate. A BNC connector is provided for synchronisation with an external video input should this prove necessary.
Having completed the back panel we shall pass around to the front, noting on the way metal extrusions which look remarkably like heat sinks - to prevent your chips from being fried!
First on the left is the timecode generator with screwdriver-operated level control. The outgoing timecode standard can be selected to be 24 frames per second (for film), 25fps EBU, 29.97fps SMPTE drop-frame, or 30fps SMPTE non-drop. Resetting the generator will automatically start it at 01.00 hours, less 15 seconds pre-roll time. Alternatively, the generator can be jam-synced to incoming code, automatically setting itself to the correct standard and time value. This facility could prove very handy. Suppose that for reasons of tiredness or excess fluid intake, you accidentally erased a few seconds of timecode. (If you do ever manage to do this, you will need a better explanation!) The jam-sync facility would enable you to sync up to existing code and drop in to paper over the crack. The Pacer is capable of 'flywheeling' over any small gaps left.
Another problem that could conceivably occur is if you are given tapes to work with having insufficient pre-roll to allow your machines to sync up before the start of a programme. Sounds pretty bad, but you can turn the striped tape upside down and the Pacer will jam sync to backwards timecode and allow you to extend the pre-roll. I'm impressed! (Remember that timecode is on track one when you do this!)
Progressing to the right, we have the lock type selector button and three indicator LEDs. Three lock types are provided - frame, auto and phase. 'Frame lock' locks two timecode values together, number for number (plus or minus any offset loaded). 'Auto' mode achieves sync by comparing timecode values, but after reaching lock it only looks at frame edges. The advantage of this mode is that if you have an edited tape where the timecode is discontinuous, then the Pacer will simply 'roll over' the edit and carry on regardless. Frame lock would send the slave machine rushing to catch up with the master, which might not be a good idea. 'Phase lock' compares frame edge only. This can be used to lock to video sync pulses and thus ignore timecode, or with a bit of circuitry can lock to the 50Hz pilot tone from a Nagra recorder - useful in the film world.
The calibrate button is a bright red colour in contrast to the sober black of the rest. This ought to indicate even to the uninitiated that this means 'do not press very often' at one extreme, ranging to 'self-destruct in ten seconds' at the other! Indeed, until you change either your master or your slave machine you will only have to press this button once. Briefly, the calibrate button allows the Pacer to learn the characteristics, tach rate etc, of your machines. The function has battery back-up and will retain these characteristics in memory when your mains power is switched off. Next to the calibrate button, the external reference LED indicates whether or not video syncs are present at the BNC on the back.
The function that will concern the synchroniser user most is the offset programming. What this means, briefly, is that very often the numerical value of the timecode on the slave machine will be different to that on the master. If this is the case, then a correction factor or 'offset' will have to be loaded. It is obviously important that this facility is easy to use and quick to operate.
On the Pacer, four buttons control the setting of the offset. Auto offset initialises offset values. To do this both master and slave are played a little way so that the Pacer can find out where it is on both machines. The offset trim buttons (+ and -) can then be used to advance or retard the slave. Using these two controls it is very quick to find a rough offset position. When finding the precise offset, or when you want to change the offset slowly and inaudibly (as a broadcaster might), the subframe button enables changes to be made in fractions of a timecode frame. An LED shows whether an offset is loaded.
The chase enable pushbutton does what it says and brings the Pacer on-line, and the slave machine under its control. When the chase LED is lit the slave will follow the master wherever. Holding the button down acts as an emergency stop. For example, if you are in frame lock mode and there is an edit in the timecode, the slave will go hurtling off trying to find what it thinks is the correct point on the tape - which may or may not actually be on the tape! Think of this therefore as a panic stop button, although in normal usage this should not be necessary.
Three LEDs on the far right end of the unit give you confirmation that timecode is coming from both master and slave, and whether tach information is being received as it should. Another LED shows when the two machines are locked. (This lights at quarter-frame lock.)
So, that completes the rundown of features on the Pacer itself. Before coming to the Pacer Pad, which is essentially just a more sophisticated means of control, we shall have a look at how the main unit performs.
In use, the Pacer is so straightforward that we can all take to it like ducks to water. The review unit was connected to a Sony low-band U-matic video machine, which of course was the master, and an Otari multitrack. Using the calibrate button took just a few seconds for the Pacer to align itself to the two machines.
Setting a rough offset was a doddle, although a precise setting was made tricky by the nature of the material we had available - an atmospheric Gary Numan video with sparse patches of lip-sync. The subframe button allows adjustments as fine as one hundredth of a frame to be made, and it took a few minutes to achieve a perfect result. A practised operator working with more staightforward material should be able to cut this time down.
Once the offset was programmed, the video could be wound in the forward or reverse direction, the Otari keeping pace. U-matic videos wind tape quite slowly compared to audio recorders so the Otari machine was automatically toggled between fast forward and rewind continuously to achieve a matching speed. There would obviously be no point in racing ahead as it doesn't know where it is going until the master stops. Going into play, the quarter-frame lock LED came on very quickly showing that the Pacer has a tight control over the slave in wind mode. Worst case was about ten seconds, this being when the video was fast wound, rather than shuttling the tape in picture search mode.
In search mode on the video, the Pacer receives timecode, whereas in wind it only has the control track pulses to work on, and additional positional uncertainty occurs because the tape has to be laced and unlaced from the video head drum.
I should mention in passing that it is usual for C-format video machines to output timecode rather than control track pulses in fast wind mode - which can be much faster than wind speed in cassette systems. The Pacer's timecode readers are more than capable as they can read code from 1/20th to 80 times normal play speed in both directions.
It is sometimes a cause for concern in synchronisers that wow and flutter from the video machine can be transferred due to the synchronising process to the audio slave. This could be a problem if you have to work with a dodgy cassette in a VHS or Beta machine. Audio Kinetics specify that the Pacer adds less than 0.02% to the normal wow and flutter figure of the slave, riding over any slight disturbances. Certainly, I could detect no untoward wobble in Mr Numan's atmospheric bass notes.
Drop-outs in timecode could also be a problem. As luck would have it there appeared to be drop-outs on both master and slave caused by dirty heads, worn tape or whatever. This was indicated by the occasional flashing of incoming timecode indicator LEDs. Once again no audible difficulty was detected, and there was no loss of sync.
Tested with these two machines I found the Audio Kinetics Pacer to be spot on in both operation and performance. Having set the offset, one could almost forget that there were two separate machines connected by nothing more than wire. I would always keep a lookout for that 'lock' LED though - just to be sure!
The Pacer Pad duplicates some of the functions available on the main rack-mount unit-the chase enable function and offset programming, for instance.
Offsets are obviously more easily done sitting in your comfortable chair at the console, in front of the video monitor, rather than crouching over the equipment rack in the corner of the room. It also allows setting of record drop-in and drop-out points on the slave which could be useful for dialogue replacement, although the looping function would have to be provided elsewhere. (Some Sony VCRs have a loop setting function.)
My first impression of the Pacer Pad was that it did not seem to do very much for the money, but after thinking about it for a little while (and Audio Kinetics have thought about it much more than I have!) it does in fact perform all the functions one could reasonably expect of a chase synchroniser remote control. The only exception being the lack of a 'zone limit' function, to prevent you from spooling of the end of the tape. Aside from this, the drop-in function would probably be the clincher for a potential Pad purchaser.
Definitely! For a reasonable outlay, a budget 16-track studio can break into the lucrative world of video - and be capable of work of broadcast quality. After all, most post-production work is done using a U-matic copy of the master video, the resultant soundtrack being taken to a layback suite for remarriage with the picture. Even the humble VHS machine can be pressed into service in this manner. (More about this in a forthcoming article!)
For those into pure sound, how about linking two Fostex B16s together with a Pacer synchroniser for 30-track operation? This would still be cheaper than buying the cheapest 24-track recorder that I know of, and be hardly less quick in operation.
In conclusion, the choice between the Pacer and its main competitor, the Fostex system, is not going to be easy.
My advice would be to get a hands-on demonstration using identical machines to the ones you will eventually be using, and actually learn to use the system - then you will be sure. Happy synchronising!
My thanks to David Neal of Audio Kinetics for use of their demonstration facilities.