Yamaha MD4

Using MD Data disks to deliver superb quality digital sound in a familiar package, does Yamaha's digital 4‑track finally sound the death knell for the humble cassette multitracker? Paul Ward spins the wheel of fortune...

When we think of the great musical technology landmarks of modern times, the humble analogue cassette multitracker is something of an unsung hero, given the ease with which the format has become an integral part of musical life. Over the years the multitrack cassette format has been continually refined, such that today's models are capable of producing truly excellent results. But with that slightly 'squashed' sound, and the limited number of bounces possible before tape hiss becomes a real problem, the cassette was always going to struggle against the new breed of digital formats.

MD Data

It was therefore only a matter of time before manufacturers found a way to deliver digital sound in a 'cassette multitracker' package. Fostex's DMT8 and Roland's VS880 chose the integral hard disk route, while Yamaha's new MD4 and Tascam's 564 have both adopted a new digital multitrack format that records onto low‑cost removable MD Data disks.

The MD4 manual takes pains to point out that an 'MD Data disk' is not the same as a 'MiniDisc'. Currently, the former is primarily used for computer data storage applications, whereas MiniDiscs are used for 'home' music systems. Although the MD4 will happily play back material recorded on a MiniDisc, it cannot record on it. Both disk types come in playback‑only and recordable versions, although it should go without saying that you will need recordable MD Data disks to produce any home‑grown results from your MD4.

Familiar Package

Anyone reasonably familiar with any cassette multitracker should quickly feel comfortable with the layout of the MD4. To the left of the control surface are four mixer channels, switchable between the mic/line inputs and track playback. The Mic/Line input sockets are of the standard quarter‑inch jack type, as are the footswitch input and the headphone output located on the front edge of the casing. Each channel control layout follows a fairly usual pattern — Gain at the top, followed by the EQ section, the Group Assign switches, the Pan control, the Mic/Line switch and, finally, the channel fader. I might have hoped for a Mute switch, but then these didn't find their way onto many cassette multitrackers either!

The MD4's EQ is typically basic, with 12dB of cut or boost from the shelving 'High' (12kHz) and 'Low' (80Hz) controls, and the peak 'Mid' (1kHz). A sweepable Mid would have made for a more satisfying range of control, but as it stands, the character of the EQ as a whole seems to work well for subtle tonal balancing.

One auxiliary send is provided, operating post‑EQ and post‑fader, and emerging from the MD4 via another quarter‑inch jack socket. I would like to have seen a second auxiliary send, but the added flexibility of the separate track outputs mitigates this to a large extent (see later).

The pair of Group Assign switches follow familiar principles. These allow the source input to be routed to either the track 1/2 buss or the track 3/4 buss, with the Pan control positioning the signal to odd (pan left) or even (pan right) tracks as required. At mixdown, the Pan control takes on its conventional role of positioning sounds across the master stereo left/right outputs.

The MD4 is generous in its provision of signal inputs. Over in the Master section, we find a level control and grouping switches for both the stereo auxiliary input and a stereo 'Sub' in. The auxiliary returns are again in the form of quarter‑inch jacks, whilst the Sub inputs employ phono connectors. The Sub input is ostensibly designated for the connection of an external submixer, although there is no reason why it should not also serve as an extra pair of EQ‑less, line‑level inputs. If we include the four Tape Cue controls, this brings the possible total of simultaneous audio signals to 12, which is not at all bad for such an unassuming device.

The monitor selector is friendly and flexible, enabling signals from the main stereo buss, both of the two stereo group busses and the cue buss, all to be switched in at once — if required. A dedicated control adjusts overall monitoring levels and the ganged stereo master fader completes the Master section.

Action Station

To the right of the control surface things require a little more thought for those used to cassette‑format recorders. Towards the back is the door, with attendant Eject button, wherein the MD Data disk is slotted before pushing the door back down. Beneath the large, clear LED screen (how pleasant to type those words...) are the main controls. Some are familiar enough; nearest the front edge are the transport keys (although the Fast‑Forward and Rewind controls need a little explanation — more later), and it's easy to make out the Track Record Select buttons. With little more than this level of understanding it would be perfectly possible to bluff your way through a basic recording session on the MD4 — and, indeed, I managed to do just that.

Although the MD4 is a digital recorder, all bounces are passed through analogue circuitry, so the number is not infinite.

To record a take, merely set the channel Group routing, press one of the four Track Select buttons, press Record, adjust the recording level, and finally press Play. Before entering record mode, the MD4 display shows a red flashing ring around the track to warn that the track is armed, changing to a steady red ring as recording commences. Nothing too scary there...

Punch‑ins may be made by setting the desired Track Select button, pressing Play, and then hitting the Record button at the appropriate moment. Alternatively, the Record button may be pressed first (which begins playback), followed by a Track Select button. For the player whose hands are busy with other things, a footswitch (not supplied) will start playback at the first press, drop in at the second, drop out at the third press, and go into pause mode on the fourth. When in normal playback mode, the footswitch toggles between playback and pause — a useful facility for the control of backing tracks during a live preformance.

Instant Search & Locate

The first culture shock comes when pressing those 'FF Cue' and 'Review' buttons. It is so easy to believe you are working with a cassette‑based system that, at first, it is tempting to hit the Rewind button to go back to the start of a recording. What these buttons do, in fact, is to cue through your recording at x2 (single press) or x4 (second press) speed. To get to the top of the section just recorded, you simply press the 'Last Rec In' button. No waiting for the tape to wind, no clunks or clicks as the transport does its stuff, and no tape slippage to mess up those cue points. Superb!

Locating specific points in a song is an important part of the multitracking process and it is here that digital recording can really score, with its fast, accurate cueing. Yamaha have obviously understood this advantage and endowed the MD4 with several search functions to make the recordist's life easier.

The start of individual songs is located by the Song Search buttons (Forward or Backward). When recording a new song, the Song Search Forward button is pressed to position the MD4 at the next available area of blank disk space, annotated in the display as 'Blank Top'. The Song Search Backward button may be pressed at any time during playback to locate to the beginning of the current song.

The aforementioned Last Rec In/Out buttons simply set the current position to the start or end of the last recorded take. These locate points are automatically updated and stored by the MD4 when any recording is made, but are unfortunately lost once a disk is ejected or the MD4 is powered down.

Up to eight markers may be set within a song, during playback or recording, simply by pressing the Mark button, and a pair of Mark Search buttons allow you to move forwards or backwards through these markers — all performed in an instant. The display always shows the markers used so far, and the nearest marker prior to the current song position flashes — a nice touch.

The Last Rec In/Out and the eight marker points are adjustable in single frame steps up to five seconds either side of the mark point. When making such adjustments the MD4 plays back 1.5 seconds of audio before and after the mark point. Usefully, the volume of the two sections before and after the mark differ, and the user can select whether the pre‑mark or post‑mark signal is the louder. This is especially helpful when compiling markers to act as Cue List points (more later). When the ideal marker point is found, a press of the Enter button stores its new position. Markers are cleared by pressing — surprise, surprise — the Clear button.

Within minutes the technicalities of the search functions ceased to be of any real concern, and I found myself zipping around my recording with little regard for anything but the music I was making — which is certainly the way it should be.

More esoteric functions include the ability to repeat a song, repeat all songs, or repeat between mark‑able A/B position pointers. The Program Play function allows you to compile a list of song numbers on disk for playback, with up to 32 steps. Although these features may have more in common with typical hi‑fi components than typical pro audio — given the MD4's ability to replay pre‑recorded MiniDiscs — they are welcome all the same.

The subjective sound quality is leagues ahead of any analogue cassette recording...

Auto punch‑in/out and rehearse features are made all the better for the accuracy of digital location. Punch‑in/out points may be set on the fly or tied to the current time position. Once set, the drop‑in may be rehearsed as many times as necessary, before committing a recording to disk, with the MD4 muting the record track at the correct point. I was a little bemused by having to set the punch‑in point by way of the Rehearse button, whilst the punch‑out point is set by the Play button! Wouldn't it have been much less confusing to use the Rehearse button in a similar way to the A/B repeat? Auto punch‑in may also be initiated from a footswitch, with up to nine seconds of pre‑ and post‑roll time available.

Track bounces are rehearsed in much the same way as punch‑ins, with the usual facility to add extra live tracks via the mixer channels. Although the MD4 is a digital recorder, all bounces are passed through analogue circuitry, so the number is not infinite. I managed to bounce five or six times before I noticed the sound becoming 'brittle', but in comparison with analogue cassette recordings the results were still excellent, with little or no discernible hiss being added for each pass.

One feature that I am particularly pleased to see is the Cue List. This allows the user to compile a list of edit points to create a new song, using the markers previously specified. I was quite unprepared for such an advanced digital editing feature on the MD4. Admittedly, there is a maximum of nine steps of up to nine repeats each, and Yamaha suggest that in rare circumstances playback may not be continuous, but in my brief time with the machine it performed flawlessly. Once you are happy with your Cue List, it's a simple matter to copy the newly created song elsewhere on the MD Data disk (assuming you have free space) to save the fruits of your labours.

Both the disk and individual songs may be given titles which will appear in the display when loading up a disk or selecting a new song. I entered over 100 characters before I got bored — so maybe this could be the place to note down your lyrics! When first selecting a song, your complete title will scroll from right to left before settling on the first eight characters as a steady display. Talking of which, the time display is switchable between the time elapsed from the top of the song, time remaining for the current song, or the total elapsed time from the top of the disk.

Varispeed fans will be glad to learn that the pitch can either be fixed or is variable between ‑6.15% and +6.13% in roughly 0.15% steps.

Quality Time

There is still controversy about the compressed digital data formats utilised in DCC and MiniDisc machines. The MD4 uses ATRAC (Adaptive Transform Acoustic Coding) compression, which basically compresses audio data to one fifth of its original size, using psychoacoustic masking principles to determine those areas of the audio spectrum that are least likely to be missed by the human ear. ATRAC permits an MD Data disk to hold up to 37 minutes of 4‑track audio, rising to 74 minutes of stereo and 148 minutes of mono. The recording mode is set in the Utilities menu and recordings in any of these modes may share the same disk. I tried some stereo recordings of my CDs and, to be fair, I could hear a subtle difference when listening very closely — especially on some of the low‑level reverb tails, but I certainly wouldn't get worried about it for multitrack work. The subjective sound quality is leagues ahead of any analogue cassette recording and the unwanted side‑effects of dbx or Dolby noise reduction are much worse than anything I could detect from the ATRAC system used here.

There is one aspect of the MD4's operation that I take particular exception to — TOC updates. 'TOC' refers to the Table Of Contents area held on the MD Data disk. The TOC contains information about what is recorded on the disk, the disk title, song titles and so on. The TOC Edit indicator lights up when the TOC needs to be updated, usually after a new recording or edit. But it is left up to the user to update the TOC before ejecting a disk or powering down the MD4. Failure to do this can lead to lost data. Fortunately, the procedure for making the TOC updates is little more than pressing the Stop button while the machine is in a stopped state, but I find it a little galling to have to take care of such mundanities. To be fair, the MD4 refuses to eject a disk until the TOC update is made — but why can't it just make the update itself before ejecting the disk? Only once did I forget to update the TOC before switching off the power — and I won't be in a hurry to do that again!

There is no digital output on the MD4 and also no facility to make copies of songs other than to the same disk, though I doubt this will concern most potential users. However, the four separate track outputs are a delight to behold. By making use of these direct outputs and treating the MD4's mixer inputs as direct track inputs, the MD4 will integrate into a larger system as easily as it will function as a stand‑alone mini‑studio. For the MIDI musician who merely wants to add a few audio tracks to his compositions, this machine will do the job admirably (notwithstanding the fact that MIDI Machine Control would have made for better integration into a typical MIDI sequencing system).

Although first off the mark with the MD4, Yamaha will soon be up against some stiff competition with the imminent release of Tascam's 564 MiniDisc Portastudio [previewed last month; SOS August 96]. This machine purports to include a digital output, bounce‑forward, undo and MMC amongst its armoury, although it appears to lack some of the MD4's appealing instant search and locate functions. At the time of writing, however, Yamaha's recorder does seem to have the edge on price.

Conclusion

The MD4 has a lot going for it. The sound quality is obviously a big step up from analogue cassette, and the ease with which locate points and drop‑ins can be manipulated is something of a revelation — and don't underestimate the advantages of a display that can be viewed from the opposite side of a room! It really is only a very short time before operation of the MD4 becomes second‑nature and a return to the drudgery of tape‑wind controls seems like trying to swim with lead flippers. The auto‑punch and rehearse features make life about as easy as current technology will allow for the sole bedroom musician. Make no mistakes, though — the MD4 is perfectly capable of producing audio of commercially releasable quality, and will undoubtedly go on to do so.

Anyone currently contemplating a high‑end, cassette‑based 4‑track machine would do themselves a serious disservice if they didn't at least consider the MD4. The extra outlay might just make the difference between producing rough demos or polished, edited masters. Aah, the wonders of progress...