Soundcraft already has some experience with the microprocessor-controlled tape recorder, gained through its two track machine which has been around for a few years. Now here is the Saturn which is doubtless intended to take Soundcraft into the big-time multi track market, heretofore dominated by machines such as the Studer A-800 and the Otari MTR-90.

Although memorised push-button alignment ideas have been incorporated for a while in stereo tape recorders (see page 64), they have not really found their way very far into multi track machines to date, which is interesting when one considers the time spent lining up a large multi track in the studio.

For some years there has remained a hole to be filled in this particular area of demand: one which appears to be satisfied by the arrival of the Saturn, especially when one considers the provisions that have been made for partially automatic set-up.

Saturn is initially provided with 24 track capability, although a 16 track option is going to be made available, involving the replacement of a head-block which the machine will recognise as being different. I presume that this option would mean that the slightly poorer customer could opt not to purchase the audio channel cards for the last eight tracks. It's worth noting that the machine holds two separate memory banks, one for each headblock, so that parameters stored while one headblock is installed will be remembered independently from those stored while the other is in place.

TRANSPORTS OF DELIGHT

Although the Saturn's transport looks fairly conventional, the designers must be complemented on achieving extraordinarily low wow and flutter specifications. We are talking about figures of less than 0.01 per cent DIN peak weighted at 15 ips, with many machines as low as 0.006 per cent, due partially to the provision of rolling tape guides instead of the usual fixed guides, reducing the scrap component to a minimum, there being no fixed components in the tape-path during play mode. The capstan system is conventional, using a metal shaft and a pinch roller, and the capstan motor carries a fairly massive flywheel, which is perhaps a little old-fashioned but nonetheless quite clearly successful.

There are one or two disadvantages to the high-mass capstan system, mainly in the time taken to change speeds, or to reverse the motion of the tape, which can take quite a few seconds. Initiation of PLAY is locked out until the capstan servo locks at the new speed or direction. This reverse-play possibility is nonetheless a good idea for various special purposes, and more advantages could be realised if the change of direction was made faster with the incorporation of a tighter servo and lower-mass capstan. It might then be difficult to achieve such good wow and flutter figures, so perhaps you can't have your cake and eat it!

The capstan runs all the time (in STOP mode, etc.) and the time taken for the machine to reach stable play-speed from STOP was very fast. The Saturn incorporates a tension take-up system for establishing idle-tension once the tape has been loaded, and one marvellous feature is that which detects the imminent arrival of the end of the tape so that it stops from rewind or fast forward before it all spools off the end; this would be great if you have a studio where the tape machines are housed in a separate machine-room. A double-press on the rewind or forward buttons overrides this safety feature, allowing the tape to spool right off.

Varispeed and "varispool" facilities are comprehensive, and can be set over a wide range (varispeed from -50 per cent to +100 per cent).

MISSION CONTROL

Soundcraft has managed to keep the overall size of the Saturn down quite a bit, compared with its chunkier rivals, by siting all the controls in a remote panel, which in itself is quite small.

The only controls which would normally be resident on the machine are straightforward things such as STOP, PLAY, and the basic autolocate commands, although it is optional to install the audio alignment panel on a strip which runs along the front of the machine at the top right hand side if you don't go for the remote meter package which is standard (there is an option to have large VUs mounted on the tape machine itself).

The "total remote" consists of autolocator, varispeed, monitor switching matrix, record mode matrix and various programmable function controls. Above this, on an angled bracket, would normally be the twenty four remote meters and the thin strip below it housing the audio alignment section which incorporates a little LCD display showing messages relating to the current status. All the standard monitor modes can be selected either for all tracks or for individual tracks, and it is possible to "solo" tracks in replay or sync so that the other track outputs are muted. Up to four complete set-ups of monitor status may be stored in backed-up memory (this doesn't include record-ready's).

Some novel work has been done to improve drop-in and drop-out flexibility by allowing the user to program not only which tracks are to drop in when record is pressed, but which will drop out as well.

In this way it would be possible to be recording on a group of tracks while setting up a second group containing some new tracks to drop in and some existing tracks to drop out at the next drop-in. It is also possible to defeat the bias/erase timing delay on drop-in, so that immediate recording (with the ensuing slight overlap) can be initiated; but the bias/erase timing is still retained at drop-out for "gapless" performance.

Soundcraft has provided three user-programmable keys (called f1, f2 and f3) which can store up to 32 steps of operation (this is becoming quite common on microprocessor-controlled equipment). Each of these 32 steps can be one of the remote unit's keys, including the other function buttons, so that a single press on one of these might initiate the notional sequence: "rewind to memory one, go into play until memory two, record ready tracks two and three, record until three, STOP." This makes operation extremely flexible, allowing programmable punch-in points and overdub sequences easily repeatable, eliminating the manual panic of dangerous drop-ins! Subsequent editing of the function key sequences can be performed easily.

AUTOLOCATOR

The autolocator is a standard feature of the Saturn and provides 10 locate memories which may be used in operations such as that described above. Memory locations may be cycled between, and the "until" key may be used to define a point up to which the machine will play or record.

There's also a nice addition which allows you to add an offset to a memory locate operation, giving possibilities like "locate memory one plus 10 seconds", which is good if memory one is the start of a track and you need to go 10 seconds into it. Return-to-zero is on a dedicated key, which if pressed twice will cause a "return-to-play": the last point at which the machine went into play.

SOUND CRAFT

All audio alignment for the Saturn is achieved using an assignable control strip located either on the total remote or on the machine, containing up/down buttons for adjusting all the usual audio parameters like EQ, BIAS, LEVEL, etc., as well as a few less common operations like phase compensation and record LF EQ. This almost completely eliminates the need for a screwdriver.

A number of time-saving features have been incorporated into the line-up procedure, such as the "auto channel increment", which means that as you store the alignment setting for, say, BIAS on track one, the system automatically moves on to track two, ready to align its bias, and so on. There is also a MASTER control which enables incrementing of all tracks together; very handy if you want to change the reference level for the whole machine and would rather not have to go through every track individually, changing its level control. The user is reminded to STORE each parameter after setting it, which helps to get around the problem which a lot of people find with this type of alignment; that of moving on to the next parameter and losing all your hard work on the last one!

While on the subject of level control and audio alignment, mention must be made of the machine's comprehensive audio oscillator, which, in conjunction with wideband onboard VU meters, make it entirely possible to line up the machine with no need for external connections.

The built-in oscillator can generate either sine or square waves over a wide range of frequencies (whose values are indicated on the LCD as selected), these being the most commonly encountered frequencies in tape machine alignment processes. It is important to realise, though, that the sine wave oscillator will not have very low distortion, as it is only intended as a level reference, and that Soundcraft only guarantees the 10kHz, frequency to be accurate (for adjusting bias), whereas the other frequencies may be within 10 per cent.

A 10dB attenuator can be brought in, so as to lower the output level of the oscillator when aligning at either low speeds or high frequencies (taking the signal below the possibility of magnetic saturation), and in this case the gain of the meters is raised by 10dB to compensate. It is possible, if necessary, to inject an external oscillator of higher quality on a socket which is provided, and this will be routed to all the channels so that distortion measurements, etc., could be made accurately.

Four user-selectable memories are provided for record alignment settings, and these do not affect the replay characteristics, which appear to be stored in memories associated with the tape speed and EQ standard (NAB, IEC, AES). It is interesting to see how Soundcraft has eliminated the need for separate sync amplifiers, by using the computer memory to change the single replay amp characteristics in sync mode so that it is optimised for achieving the best response, while the same amplifier will also be used in repro mode, just by changing the EQ settings. This is possible only because the characteristics of the amplifier can be changed so quickly by the microprocessor, and because you can never select both sync and repro modes at the same time!

AUTO ALIGNMENT

The architecture of the Saturn lends itself to the implementation of auto alignment facilities at a later date, and to this end a slot is left vacant in the machine for the insertion of a card (perhaps optional) which would perform this function.

A few moments thought will probably bring you to realise that this would be a relatively easy thing to do on the record side (if the replay side were lined up), but really rather difficult on the replay side, because the tape machine wouldn't know what sort of test-tape you have! All sorts of problems could ensue if the machine were made to recognize any frequency tone on any test tape at any level, not least in the cost of development; you can imagine the situation where the replay amplifier is so far out of alignment that the microprocessor has no idea whether it is looking at a -10dB tone at too high a level or a 0dB tone at too low a level. I therefore suspect that this option will probably perform automatic record alignment only, which would still save a lot of time when 24 tracks are at stake, although things like azimuths and the whole replay side would still be your responsibility.

Looking at the auto alignment problem practically, it is almost certain that replay alignment would be less frequent than record, unless your studio was doing a lot of work which involved replaying tapes from other places, in which case the replay side would be changed a lot. For straightforward multi track recording work, the replay side could be left alone for quite some time, while auto alignment could be used when loading a new reel of tape, so as to optimise its performance.

REMOTE FACILITIES

Parallel and serial remote sockets exist on the rear panel, the serial remote being primarily intended for use with the long-awaited SMPTE/EBU remote control bus, which we might actually see soon. Normal parallel synchroniser interfaces could easily be connected, and I believe that a number of the most popular synchroniser manufacturers have already done their bit in this region.

A time-code reader is planned for the Saturn, although it is yet unclear as to whether this will go the whole hog and fulfil the role of an on-board chase-synchroniser. The position display on the machine already has a blank window ready to read time code frames.

FINALLY...

Liven the Saturn's extremely competitive price — £31,450 (when compared with other top-end rivals) and its potential for future development, coupled with what appears on balance to be excellent performance, it seems that the machine could live up to its name and run rings around the competition. It's quite a long time since a British manufacturer scored in the multi track recorder market.