The innovative single-stack 6-track head developed for use in Sansui's WSX1 cassette recorder/mixer [reviewed SOS December 1989] also forms the basis of the separate MR6 recorder, not only enabling those with a preference for component systems to take advantage of this new cassette multitrack format, but also forming part of a much larger system concept. A synchroniser, the SY1, allows transport lock-up between an MR6 and either a WSX1 or another MR6, providing a total of 10 audio tracks (with one track of each recorder dedicated to sync code). With this in mind, the Sansui component range is augmented by the MX12 recording mixer, a small 12-input desk with six subgroups, making an ideal companion for a pair of MR6s. Let's find out how well they perform...

MR6 RECORDER

Sansui's MR6 recorder is certainly impressively built. Housed in a 3U high case with sturdy detachable 19" rack ears, and finished in attractive light grey, it has a solid look of robust quality and functional efficiency. In common with those multitrack cassette units which aspire to high performance, the MR6 runs at double normal cassette speed (with a 20% varispeed) and is aligned for Type II tapes only. Cassettes of no greater than C60 length are specified, with the thinner tape of C90s presumably being felt insufficiently robust to withstand the constant shuttling that is inevitable in multitrack usage. A C60 running at 3.75ips, in one direction only of course, gives a playing time of 15 minutes.

The cassette housing is shielded by a flip-up perspex cover, giving excellent access to the heads and tape path for cleaning and maintenance, but necessitating the cassette to be manually positioned on the hubs by the user. A sprung claw arrangement grasps the base of the shell at either side to retain it in the correct position, though their grip is a little less positive than it might be, I feel.

As on the WSX1, the Erase head and the usual combined Record/Play head are mounted on very nice, solid-looking, cast head carriers as opposed to the pressed fabrications found in cheaper transports. The dreaded tape 'flutter' that afflicts so many cassette machines is at present subjectively minimal and will hopefully stay that way, but only a lengthy period of sustained usage will answer that one. Machine noise (eg. capstan whine and output hum) is very low - a legacy of good construction - although the MR6 headblocks make a rather loud clunk as they are driven to and from position, which is unfortunate as this happens rather a lot during the synchronisation process.

Dolby C noise reduction is employed, providing reasonable noise suppression with a minimum of noise modulation side-effects. This can be switched out, though the noise performance is not really acceptable without it. A Sync switch is provided which removes track 6 from normal functioning, for use with timecode or the Sansui system's own sync code, presumably defeating its noise reduction as well as re-routing it to the dedicated sync sockets on the back panel. Sadly, there is no specific configuration for protecting track 6 from accidental erasure.

Transport functions are controlled by a block of large, flush-mounted, soft-touch switches. Entering either Fast Forward or Rewind mode directly from Play gives you a Cue monitor signal for as long as the switch is held down, reverting to Play as soon as it is released. To achieve fast wind you must in fact first go through Stop, which takes a bit of getting used to if you are familiar with more conventional transport logic. I am not really convinced of the value of such 'cue and review' functions in normal multitrack recording, especially when there are simple autolocate functions present, such as the Sansui's Rehearse facility. Auto functions are entered by pressing the Start button, which automatically resets the counter to zero and sets the transport to Play. Subsequently pressing the Rehearsal switch memorises the current tape position and enters Rewind, playing from zero to the memorised position repeatedly.

As an alternative to the auto-rehearse facility, Zero Return can be activated during auto-play. This will also memorise the current position and automatically rewind, but park the tape at zero, waiting for a Play command before repeating the cycle. In non-auto mode, Zero Return performs its obvious function and can be activated from any mode, not just Stop as on some transports, although it is not clever enough to find zero when it is already beyond it and in fact resets it. Although a Pause switch is featured, I can not discern any operational difference between Pause and Stop, for both modes retract the heads as well as stopping the transport. With multiple pausing being used in the syncing process, it would surely have been better if a more 'traditional' Pause mode had been employed, with the heads remaining engaged, thus obviating the need for all the transport clatter during the early stage of synchronisation.

Six record selector switches determine the status of each tape track in conjunction with the informative illuminated display located just above. Selecting a track to Record Ready produces a display in red, which reads 'DIR' and doesn't really make a lot of sense unless you are familiar with the WSX1 and realise that this is the same display module. 'DIR' (short for 'Direct') actually means something in that context, but I suppose it does the job as well as any other red light once you are used to it. A small flashing red circle also appears in the display unit until the master Record switch is selected to enter Record/Pause mode. Recording is activated from Record/Pause via Play, with the Record indicator then remaining illuminated. Personally, I would prefer a little more visual confirmation of Record mode, and feel that an LED above or within the Record switch itself is a minimum requirement.

A four-digit electronic counter completes the active part of this display block, counting in arbitrary units (not real time) and about as accurate (ie. inaccurate) as the WSX1. Zero will drift quite significantly during even a relatively short overdub 'cycling' session, which rather undermines some of the potential value of the Auto functions in practice. It is a minor irritation also to have to re-define zero in order to use the Rehearse function; a second memory point really would have been an asset here.

"The Sansui 'Hyper Sync System' employs a proprietary linear timecode, similar to but incompatible with the commonly used SMPTE/EBU."

The MR6's second display handles audio metering via six 12-segment LED ladders. The segments are unusually wide and, although the colour change at 0VU (from orange to red) is not particularly dramatic, they are easy to read despite their very short 'travel'. A temporary peak hold feature helps visual detection of transients, which would otherwise be too fast to register on the LED meters.

With the exception of a ¼" jack socket for the footswitch drop-in facility, all connections are made to the rear panel of the MR6. Twelve phonos handle line input/output for the six audio tracks, plus an extra pair dedicated to sync signals, with the Sync Out socket governed by its own output level control. The MR6 interfaces with the outside world, for both sync and normal audio sockets, at the nominal -10dB standard level. A standard five-pin DIN socket (labelled 'Slave 1, To: Master') and a less common eight-pin DIN socket (labelled 'Slave 2') are used to interface with the SY1 Sync Control Unit for 10-track operation.

SY1 SYNC CONTROL UNIT

Although it doubles as a remote control, the cables provided with the SY1 synchroniser are not over-generous in length, so don't plan on siting it more than a couple of feet away from the recorders. For synchronising two machines together, the SY1 employs the previously mentioned five-pin DIN link to both machines and the eight-pin link to the slave machine only. Sync Code In and Out phono sockets are provided for each machine, with the SY1 itself deriving power from one of the slaved machines.

The Sansui 'Hyper Sync System' employs a proprietary linear timecode, similar to but incompatible with the commonly used SMPTE/EBU. For slaved operation it is first necessary to stripe this code onto track 6 of each MR6 recorder; a process referred to in the manual as 'formatting'. Rather strangely, it is recommended that both cassette tapes be 'striped' on the same machine, which of course takes twice as long, as you can't do two at once.

Having formatted both tapes and rewound them fully as recommended, you can then control both transports from the SY1 synchroniser. However, lock-up can take anything up to 10 seconds, and sometimes more, depending on how difficult a task you have set the system. I am sure Sansui would not complain at having their chase-lock system described as relatively unsophisticated, for it seems to rely on momentarily pausing one of the decks to achieve a rough approximation then fine-tuning it via speed adjustment. As all audio signals are thankfully muted automatically during this operation, you tend to be very aware of all the transport activity and the motor speed slewing about. Locked condition is confirmed by the previously flashing Lock light becoming static, as well as the restoration of audio output.

It is a definite requirement that the two transports start each attempt at lock-up from as near as possible the same tape position. In practice, I found that if the two machines were more than a few seconds apart the system failed to find accurate lock-up and, after a few pauses, simply ran on 'out of sync' but with a confirmed lock shown on the indicator. I can understand why a relatively simple system such as this should need to be started somewhere near sync - after all, machines that can do this sort of thing at all normally cost a great deal more than the SY1 - but the device really should not indicate a successful lock-up condition when it plainly isn't. If you have already recorded some material on each tape deck, then you will know immediately that the two machines haven't locked up properly. However, it would be possible to make your first recording on one of the decks believing they were correctly in sync, resulting in it subsequently appearing out of sync even when the machines were properly locked!

I hope the review model is not from a full production run, for I feel this really ought to be fixed. Perhaps the fact that the Zero Return function on the remote doesn't work at all and even resets the counter, further indicates that the review model might not have been running a final release operating system. Even when the machines are correctly locked, the two counters do not always run in sync. This has no practical result, and it is easy to simply refer to just the master machine, but it is nevertheless slightly disconcerting.

"Having six subgroups, with two sets of output connections, makes multitrack operation with either one or two tape machines very simple - even for the inexperienced operator."

A secondary function of the SY1 is to operate as a Tape-to-MIDI sync convertor. Two additional Tape Sync In and Out sockets are dedicated to this function, as well as MIDI In and Out. The sync code is of the most basic FSK type, converting to MIDI clocks but without Song Position Pointers, so you are stuck with always running from the start of the track. Normal FSK procedure is followed, whereby the 'master' MIDI device must initially drive the convertor, which produces the sync code for recording, at the appropriate tempo. Replay is then under the control of the code on tape.

The system achieves what little it sets out to do without mishap, though it resisted all attempts to get it to run MIDI sync at the same time as locking two machines together. Admittedly the manual doesn't say it can do this, but I would have thought it should. I would hardly expect to find a fully-fledged timecode-to-MIDI system thrown in for free, but there are several budget time-stamped code systems already on the market, all of which give full lock-up via MIDI Song Position Pointers (SPPs) - indeed, the code used for synchronising two MR6 machines within this system must be time-stamped in some form, and could surely have been used for the MIDI side as well. As it is, if you want decent MIDI sync within this 10-track system you have got to be looking at a separate timecode unit, which means losing another audio track to timecode. The ability to use the sync code on the master machine to also drive MIDI sync with SPPs would, I think, have greatly enhanced the attractiveness of this system.

MX12 MIXER

The Sansui MX12 is a fairly basic 12 into 6 recording mixer, obviously built on the same chassis as the WSX1. Having six subgroups, with two sets of output connections, makes multitrack operation with either one or two tape machines very simple - even for the inexperienced operator. Input channel layout is very conventional and will give nobody any difficulty.

Beginning with source selection, there are separate Tape and Mic/Line selector switches. Mic/Line sources are governed by a wide-ranging input gain control ('Trim') with a -50 to -10dBV swing (50kOhms), with gain optimisation assisted by an Overload LED. The input amps are fine for all electronic instrument sources (synths, drum machines, etc) but are tested a bit more severely as mic amps. Drums or electric guitars are fine, but recording acoustic guitar, say, with a dynamic mic is asking a bit much and results in a rather noisy signal. A pair of dedicated, balanced, mic inputs are featured on channels 11 and 12 but, sadly, there is no phantom power on these and in performance they seem indistinguishable from the other channels, providing merely a more convenient means of connecting a balanced signal. A basic two-band EQ is provided, offering +/-12dB at the standard 100Hz and 10kHz frequencies. This is basic 'Portastudio' stuff really and perhaps a dedicated mixer should do better, with at least a fixed Mid control if not a swept one. As far as it goes, EQ performance is good, for it introduces little noise and is smooth and without harshness, but it can not be counted upon for significant tonal shaping.

Sansui have ditched the built-in Reverb/Delay unit featured on the WSX1, leaving the MX12 with two post-fade, post-EQ effects sends. I felt the built-in effects, despite their limitations, made a worthwhile contribution to the 'all-in-one' concept that the WSX1 embodies; but outside of that system, in the separate components world, it could easily be seen as an irrelevance and its omission here is probably justified. Aux master controls govern the summed output, sending a nominal -10dBV signal (100 Ohms). Both mono Aux sends can be returned in stereo, a pair of ¼" jacks being dedicated to each, with associated Aux Return level controls.

Three group assignment switches work in conjunction with the Pan control, using the normal odd/even logic, to provide programme output selection when recording. Signals are also routed to the mix bus (Stereo Master), via the panpot. A post-fade Solo switch soloes into the headphones for checking signals in isolation, with a Master Solo level control and LED to warn of a soloed channel. Input channels are completed by adequately smooth short-throw carbon-track faders, whose fader tops are of rather more cosmetic than ergonomic worth, making the faders difficult to move precisely with only one finger. The six subgroup faders are placed to the right of the console, separated from the input channels by the individual left and right master faders.

Unusually for a recording mixer, there are no dedicated Tape Return monitor channels, input channels presumably being assigned to this purpose in normal usage. The choice of monitor sources is governed by the Monitor Selector switches and allows only Stereo Masters or Aux Sends and Returns. Metering, which is via the same brand of 12-segment LED ladders as the recorder, can be flipped between showing all the available monitor sources simultaneously (so you can look out for overload on the aux buses when mixing) or displaying the six subgroup output levels, although these align accurately with those on the MR6 recorders so you might as well look at those to see group levels.

"...the star performer of this range is undoubtedly the Sansui MR6 recorder..."

With the exception of the two stereo headphone outlets on the front edge, all connections are made to the rear of the MX12. A selection of jacks, phonos and XLRs confronts the user, with sensible options taken as to where to use each type. All 12 Mic/Line inputs are on ¼" jacks, with inputs 11 and 12 having additional XLRs. Unusually, there is a direct output from each channel (¼" jack), enabling you to bypass the subgroup summing amplifiers on individual signals if you are willing to do some patching, hopefully achieving a cleaner signal via the more direct signal path. All Aux Sends and Returns also appear on ¼" jacks, as do the separate Left and Right monitor outputs. The stereo bus is catered for by both phonos and balanced XLRs, although I rather doubt if this mixer will be used with that many master recorders with balanced inputs. Another pair of phonos allows for injecting signals into the mix buss, such as when connecting a submixer, although I feel this would probably be more conveniently handled by jack connectors.

Conspicuous by their absence are Insert points on either masters, groups or input channels, which is surely a significant omission on a dedicated recording mixer. All Tape connections are sensibly made via phonos, with 12 tape returns and six subgroup sends - or 'PRGM Outputs' as Sansui like to call them. The subgroup outputs are doubled to facilitate connection to two recorders, allowing recording on 12 tracks without re-patching the outputs. However, re-patching of inputs is virtually unavoidable, for as you fill up the available tracks it is necessary to use the corresponding input channels as tape returns in order to hear what you have done so far. Thus, if you are using the full synchronised system with two recorders and 10 audio tracks, you will only have inputs 11 and 12 available during your last overdub.

POINTS OF VIEW

Sansui are to be praised for their bold attempt to bring machine synchronisation into the cassette multitrack domain, although the slightly fragile sync performance of the review sample tends to suggest there is still some work to be done before this 10-track system can be unreservedly recommended.

For me, the star performer of this range is undoubtedly the Sansui MR6 recorder, which warrants consideration on its own merit for anyone entertaining the idea of a cassette-based multitrack component set-up. Fine audio performance, with a quoted frequency response of 40Hz to 15kHz that out-specs 8-track cassettes, is allied to low audible crosstalk levels (50dB @ 1kHz, 0VU), with adjacent bouncing causing no problems. Even testing with SMPTE/EBU timecode (recorded 6dB below 0VU) - a signal renowned for its capacity to 'bleed' into adjacent signals given the slightest opportunity - produced perfectly acceptable results, provided a suitable source was chosen for the adjacent track, ie. preferably one that would never appear in the mix on its own, or one sufficiently continuous to consistently mask the low level of code inevitably audible on such a narrow gauge tape format.

Where you do have to be careful, particularly with the MIDI/FSK signal and to a lesser extent the Sansui machine-sync tone, is in the level and transient content of the adjacent signal, with a view to avoiding potential corruption of the reading of the code. This applies equally, of course, to many other manufacturers' machines and formats. The Sansui control code is recorded automatically at 0VU when a tape is formatted for synchronised usage, and it is recommended that the Sync Output level control be adjusted for a similar 0VU reading on replay. However, I found in practice that significantly more level was required by the SY1 synchroniser before it would attempt lock-up and eventually completed all testing, recovering the code at +6dB above 0VU, with slightly improved results.

Taking the Sansui 10-track package as a whole, perhaps the least satisfactory element is the limited facilities of the MX12 mixer, which display their 'expanded Portastudio' origins altogether too much, especially in comparison with those available on the new Tascam MIDIstudio series, for example. The small recording mixer market is fiercely competitive, and the MX12 may find itself having to fight off the opposition with only the brand-loyalty of the package approach to recommend it. I will be surprised, however, if we do not see a number of dealers creating hybrid packages around the MR6 recorder, for it is the ideal heart of either a top-end 'component Portastudio', or as the tape element in a combined MIDI set-up. Five audio tracks (the sixth is allocated to sync code, remember) are significantly more flexible than three, and may well be all some people need.

Those for whom more tracks are essential, but who feel they must remain within the cassette domain, must consider whether the benefit of the extra tracks outweighs the frustration of waiting for lock-up after every transport function. If this two-machine system used standard timecode (which could also be tapped for MIDI sync), with a better synchroniser that allowed offsets, then regardless of lock-up time I think the unique working flexibility, for a cassette-based system, might be a significant attraction. As it is, perhaps the balance of advantage lies the other way.

Sansui is obviously a company determined to innovate, as evidenced by their adoption of an entirely new track format, and hopefully this 10-track system hints at interesting things to come.

FURTHER INFORMATION

MR6 recorder £675; SY1 synchroniser £175; MX12 mixer £675 (prices inc VAT).

Fabulous Audio Technology, (Contact Details)