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Yamaha MD8

Multitrack Minidisc Recorder By Martin Walker
Published April 1998

Yamaha MD8

If you liked the look of last year's Minidisc‑based digital 4‑track machines, but need more tracks, look no further. The Yamaha MD8 manages 8‑track recording and playback, but is still priced at just under a thousand pounds. Martin Walker suddenly finds less need to bounce.

The Minidisc format has had a rough ride in this country, with minimal success (so far) in hi‑fi circles, despite being huge in Japan, where almost every complete hi‑fi system sold features a Minidisc recorder as standard. Mainstream consumer attitudes are beginning to change in the UK, partly because of heavy TV advertising by Sony themselves, but it still seems to be an uphill struggle. For musicians, though, it's a slightly different story, since Minidiscs have significant advantages over other digital audio recording formats. Firstly (and unlike DAT), the format offers random access, so that you can quickly retrieve information from any part of the disc. From the Autumn of 1996 onwards, the format had an additional advantage; you could multitrack‑record with the aid of the 4‑track Minidisc recorders that became available from around that time (for example Tascam's 564, Sony's MDMX4, and Yamaha's MD4).

The 4‑track audio cassette multitracker has always been popular for producing demos, and with care can produce very acceptable results, but however fast the tape speed, cramming four tracks side‑by‑side onto eighth‑inch cassette tape will always limit audio quality, however clever manufacturers are with built‑in noise reduction. The attraction of the 4‑track Minidisc recorders lay in their digital recording technology, which offered immeasurably low wow and flutter, distortion down in the 0.02% region, and a signal‑to‑noise ratio approaching 96dB. These machines not only attracted those who wanted to upgrade their existing multitrackers, but also put the Minidisc into competition with stand‑alone hard disk recorders, which also have random access play and record. However, compared with hard disk, the beauty of the Minidisc format is its portability — each disc is less than three inches square, and far more robust than any hard disk cartridge. This makes it far easier to change projects quickly, and swap discs with other musicians, even through the post.

If the 4‑track Minidisc machines were popular, there's now another reason to look at the format; the onward march of technology has just produced the new Yamaha MD8 recorder, which makes eight tracks of simultaneous recording or playback possible on the MD‑Data Minidisc (the same discs used by the 4‑track machines — see the 'Looking Blank' box elsewhere in this article). Better still, the MD8 retails at a similar price (£999) to the 4‑track machines when they first came out.

The Guided Tour

First impressions of the MD8 are all very positive, as many of its features have been expanded compared with its predecessor, the 4‑track Yamaha MD4 Minidisc recorder (reviewed SOS September 1996). The MD8's moulded case measures 484 by 102 by 412mm, and the controls make good use of spot colour to highlight the different functions. Two‑thirds of the case width is taken up by the mixer and output channels, with the remaining third occupied by the flip‑up Minidisc compartment, the fluorescent display and the transport controls.

There is now a total of 12 input channels; the first eight are provided with full mixer facilities, and channels 9‑10 and 11‑12 with basic stereo level and routing controls. Of the first eight, channels 1 and 2 have more extensive input options, with a choice of both XLR or quarter‑inch jack sockets (either can be used balanced or unbalanced). These channels also feature an extra TRS insert socket (post‑EQ, pre‑fader) to add outboard processing such as a compressor or noise gate if required. A single switch (located on the back panel, of which more in a moment) is also provided on these channels for 48V phantom power. Channels 3 to 8 have unbalanced quarter‑inch jack sockets.

At the top of the channel strip for each of the first eight channels is a rotary gain control, but no pad is provided, so the sensitivity varies from 'line' at the lower end to 'mic' at the other. The sensitivity of all inputs is quoted as ‑10dB to ‑50dB (referenced to 0.775V RMS, or 0dBu). Moving down the channel strip, we find an in/out switch labelled Flip. When this switch is in the Mic/Line position, the channel input is routed through the main EQ and aux send controls, while the equivalently numbered Minidisc channel is passed through a pair of rotary controls — Cue Pan and Cue Level. With the Flip switch in the PB position, this routing is reversed, which is normally more suitable at mixdown. The EQ provides three bands, each with a range of +/‑15dB, comprising a high shelving EQ at 12kHz, a sweepable mid EQ between 250Hz and 5kHz, and a low shelving control at 80Hz. There are two aux send controls, and they are both post‑fader, which is more useful for effects than for foldback use.

The beauty of Minidisc is its portability — each disc is less than 3 inches square, and far more robust than any hard disk cartridge.

Beneath the aux send controls are two in/out buttons (1/2 and 3/4) for assigning channels to the four available groups, and then come the usual rotary Pan control and a fader with a 45mm travel. Despite having such a short length, the faders feel very smooth and controllable, and better in operation than some 60mm ones that I've used on other small mixing desks. They also have a self‑sealing dust‑excluding strip — a nice touch which should help prevent crackles developing in the future. Level marking on the faders is from 0 to 10, rather than ‑infinity through 0db (nominal) to +10dB, so that the nominal position (indicated by a clutch of five lines) ends up somewhere between 7 and 8.

Good use is made of different coloured controls to highlight each area of the channel, and thankfully the knob edge markings are very clear and extend all the way down the side. The only slight niggles I had were that the knobs have no textured grip, and a few of them were noticeably stiffer in some parts of their travel than others.

The Master Section has a pair of stereo rotary level controls for the additional line level inputs (9‑10 and 11‑12) at the top, followed by the same two group assign buttons (1/2 and 3/4) as the other input channels. Below these are four Group Master rotary level controls in a vertical strip, and these control the overall levels sent to Minidisc tracks when recording via the four groups (of which more in a minute). Alongside these are the Cue Master rotary level control, and an associated Cue Mix to Stereo button, so that you can add the mix from the simple level/pan controls of the first eight input channels, providing a possible total of 20 inputs during mixdown.

Beneath these are five independently latching Monitor Select switches. 2TR In is the signal from an additional stereo input socket on the back panel, to allow you to listen to a stereo source such as a DAT machine during mixdown. The 1‑3 and 2‑4 buttons select the group busses for monitoring (pressing either one by itself switches the monitor signal to mono, so that it comes through both speakers; pressing both reverts to stereo). The Stereo button monitors the stereo buss during mixdown, and Cue allows you to hear the signals on the cue buss, which lets you monitor the sounds assigned to tracks for recording (this is useful for punch in/out and ping‑pong recording — see later). It is possible to make multiple monitor selections, but the manual does point out that this can result in monitoring the same signal at different points in the chain. At the bottom of the Master Section there is a rotary Monitor master level control, which jointly feeds the monitor output and headphone socket, and a final 45mm stereo fader which controls the level emerging from the Stereo Out sockets.

The back panel is neatly laid out, with 12 quarter‑inch jack sockets for the input channels, along with the extra insert jack mentioned earlier and balanced XLR sockets for the first two channels, with associated single phantom power switch. The two Aux send outputs are also on quarter‑inch unbalanced jacks. All other sockets are unbalanced phonos — there are eight Track Direct outs, and three pairs for 2Tr In, Stereo Out, and Monitor Out. Finally, a familiar trio of MIDI sockets (In, Out and Thru), a power switch and mains cable socket complete the arrangements. By the way, I haven't forgotten the Phones socket — it's at the front, along with an additional quarter‑inch socket labelled Punch I/O for optional footswitch control of playback, rehearsal, recording or punch in/out.

Transport & Display

The Minidisc itself is top‑loading on the MD8. As with many of the other digital recorders on the market (and like all the previous Minidisc machines) the audio material you record is arranged in so‑called Songs. After inserting a disc, the operating system attempts to read the TOC (Table Of Contents) to determine what sort of format (if any) has already been written — it is possible to record Songs in 8‑track, 4‑track, stereo, or mono modes. The fluorescent display is a mine of information, showing the current transport status, pitch mode (fixed or +/‑12% varispeed), any MIDI sync (more on this later), the Title (or other message information), a large Time Counter, Marker status, and Punch In and Out indicators. Finally, and probably most important of all, there are eight Track level meters, and L and R stereo level meters. These only have seven steps, with the track meters showing ‑36dB to Clip, and the stereo ones with a more traditional ‑20dB to +12dB. Overall, the display does bear a strong similarity to the one used by the MD4, but with additional features.

Beneath the display are the transport controls, and many of these will be very familiar: Stop, Play, Record (this one nicely visible in red), Pause, Fast Forward and Rewind, although the last two operate rather differently from how you might expect, as I'll explain in a minute. The Rehearse button gives you the useful option of trying a run through with all the signals coming off disc, mixed in with any external input signals, but without actually recording anything to disc, which makes it easy to try out overdubs before you commit yourself. In this mode, the channel meters show the input levels, rather than the output levels of any signal previously recorded.

There are eight Rec Select buttons, and two distinct modes of recording. GRP (group) allows you to record input signals using the Group Assign functions, so that for instance you could mix any combination of the 12 input channels to the four group busses. Obviously, since there are only four groups, you can only record a maximum of four independent signals in this way. DIR (direct) recording bypasses the group busses altogether (you don't have to use the Group Assign buttons or Pan controls) so that you can achieve 8‑track simultaneous recording. To choose between the two, you use the Group button alongside the eight Rec Select buttons — if you hold it down when you select a channel on which to record, a small GRP record enable light comes on beneath the appropriate channel meter display; if you press the Rec Select button alone this illuminates the appropriate meter DIR light. This is a clever way to give maximum recording flexibility without the extra cost of providing eight busses.

Join The Cue

Once you have made a few recordings, you find yourself starting to use the other cueing functions. The 'Fast Forward/Rewind' buttons are actually used for Song Search, since they skip between the start of each new Song you record. To actually move backwards and forwards within a Song, you use the Cursor shuttle/Data dial. This is a dual‑concentric knob with a centre‑sprung outside part (rather like a pitch‑bend wheel), and a freely‑rotating detented inner wheel. By pulling the outer rim, you can Cue (fast forward) or Review (rewind) during playback at five different speeds up to 32 times normal. The audio buffers still read out data at the normal rate, but from a changing start point, so you don't hear any material in reverse or at a different pitch, just chunks played back at the normal speed in the normal direction.

You can insert up to 10 markers in a song during recording or playback, and these can be adjusted or erased later. Pressing the Mark button inserts one at any time, but when you've finished by pressing the Stop button, you have to press it again to update the TOC (Table Of Contents). I know that some people find this a pain, but it doesn't take long. Punching in and out of existing recordings can be done manually using the Record and Play buttons during playback, or using any of the Rec Select buttons at the appropriate point and then the Play button again to punch out. A footswitch can also be used — the first press starts playback, the second punches in, the third punches out, and the fourth enters pause mode.

There is also an Auto Punch In/Out function — you can set the in and out points with the Rehearse and Play buttons during playback, or use the Set button in conjunction with the Last Record Search In and Out buttons. Once you have set your In and Out points, pressing the Auto Punch I/O button allows you to select either a single take, or a multi take. If you decide to opt for multiple takes, you get the option to try again after each version (up to 99 are catered for, disc space allowing), but you can't permanently save all of the takes — once you have decided which is the best, you have to choose one to paste into your song, using the Fix Take selections. Pre‑roll and post‑roll times can be adjusted from 0 to 9 seconds, to give you enough time to get yourself ready before a take. The Adjust button takes you to a different set of selections, where you can audition and change the current value of any marker or punch in/out point.

Ping‑pong recording (ie. bouncing down) is possible from any combination of tracks to any other, and you can overdub additional signals at the same time. Once again, the rehearse function can prove invaluable in setting up levels here. If you want to cycle round a particular song (or songs) you use the Repeat button, and this can be extended to Cue List Playback (with up to 26 steps), using a set of Markers within a song.

The Cue List is reached by pressing the Utility button, from which several of the MD8's more specialised functions are accessed; when you press this button, various options become available to you, which you can step through using the Data dial. This is where you choose Recording Mode (8‑track, 4‑track, 2‑track, or mono), adjust pre‑/post‑roll time settings, prepare the Cue List, or alter Program Play order (ie. the sequence in which a set of songs plays back, like on most CD players). You can also adjust the Display Dimmer (5 levels of brightness), enable/disable Peak Hold (which displays the highest level attained by each channel meter indefinitely until the Display button is pressed), or look at Disc Info (to see how your Minidisc contents are arranged, for moving, copying and renumbering songs.) One thing the MD8 does lack, however, is a dedicated bounce forward function. This is a feature included on Tascam's 564 Minidisc 4‑track recorder, whereby you carry out a real‑time mixdown of all the 564's four tracks to two tracks in the next Song location on the Minidisc, leaving the original 4‑track Song intact for you to mix down again if you're unhappy with your bounce. You can still achieve something like this on the MD8, but the procedure is more involved. It's possible to bounce down all eight of the MD8's tracks to a pair within the same Song (the MD8 is capable of reading track information from, say, tracks one and two, while actually recording a composite bounced mix onto those same tracks), but in so doing, you erase the two tracks that end up carrying the stereo mix. The only way to preserve all eight tracks individually (in order to be able to bounce down again if you're unhappy with your mix) is to make a copy of your 8‑track Song before you bounce down — a time‑consuming process. Despite the lack of this function, there are other extensive disc housekeeping functions to Copy (backup) and Move (re‑order) songs, convert them from one track format to another, renumber them, and even divide and combine them for use by the Program Playback list.

The final four options in the Utility menu are MIDI Sync, MMC Receive, MMC Device ID, and Frame Display, and these all relate to MIDI operation. The MD8 can only transmit MIDI, so you must slave a MIDI sequencer package to it, rather than the other way around, using either MTC or MIDI Clock information, but you can then use MIDI Machine Control (MMC) to remotely control the transport functions. For use with MIDI Clock, there is a 26‑step Tempo Map available for each song you record. I soon had the MD8 and Cubase VST locked together with MIDI Time Code, and was able to stop and start from Cubase using MMC.

In Use

Following the clearly written manual, I was soon in business, and despite plugging inputs into the wrong sockets a couple of times (they don't line up with the channel strips of the mixer), I had a one‑minute song recorded onto eight channels within half an hour. As most of my equipment runs at the +4dBu level, I did find the MD8's minimum gain settings a bit sensitive, but I didn't run into any clipping problems. Conversely, whacking the gain controls up to maximum gave me more than enough recording level with the mics I tried, while still keeping background noise levels acceptable low.

After being used to a computer‑based hard disk recording system, I found the tiny murmur of the Minidisc mechanics an absolute joy.

The one lingering doubt for some people with any Minidisc device is its 5:1 ATRAC (Adaptive Transform Acoustic Coding) data compression system, used to cram the same amount of audio data present on a CD onto a 140Mb MD‑Data Minidisc. ATRAC works by splitting the audio into many frequency bands, and analysing each one to find low‑level information that will be masked by much louder signals at nearby frequencies. This masked information is then discarded, and the process continues until a 5:1 compression has been achieved. Although it sounds brutal on paper, the entire process has been refined in the latest version of ATRAC to the point where many professionals cannot reliably tell the difference between DAT and MD recordings. I hope I can put your minds at rest by saying that the sound quality was excellent, and although I could (just) tell which recording was which when I carried out an A/B comparison with the original source material, the difference was extremely subtle.

To test the inevitable degradation caused by repeating track bouncing through the analogue mixer, I followed the instructions for ping‑pong recording (re‑recording any combination of existing tracks to a different track destination). Third‑generation copies were audibly different, with a slight lack of transparency and a hint of grittiness, but the difference was still very small, so I kept ponging (so to speak). By the sixth generation, the stereo image was beginning to sound rather smeared as well, but the recording was still very usable for things like background pads and washes. Since I was bouncing a stereo track, I actually had more problems keeping the two channels balanced accurately, due to the lack of precision in fader markings. If you want to record more than eight tracks, the results should be very acceptable, as long as you don't attempt to add EQ at every bouncing stage.

Conclusion

Compared with the 4‑track MD4, the MD8 offers far more than double the number of record/playback tracks — you get additional sweep mid EQ, two aux sends rather than one, MIDI Machine Control, and a total of 20 inputs at mixdown, rather than the 12 of the MD4. At £999, it is only a hundred pounds more than the MD4 was on its launch, and so must be seen as good value for money, even though the MD4 has just come down in price to £699.

If the MD8 had been launched six months ago it would probably have leapt immediately to stardom, but there are now other contenders for those in search of more than four tracks of digital recording in a convenient, cassette‑multitracker‑style package, so the choice is less clear. Other new models to look at are the Korg D8 (hard disk 8‑track, reviewed on page 190 of this issue), the new Roland VS840 (an 8‑track which records to Iomega Zip cartridge), and the Akai DPS12 (a 12‑track Jaz recorder, reviewed in last month's SOS). One thing that may steer potential purchasers towards a Minidisc solution is its lack of mechanical noise — after being used to a computer‑based hard disk recording system, I found the tiny murmur of the Minidisc mechanics an absolute joy. If you want a high‑quality integrated 8‑track digital recording solution, and favour the convenient nature of the Minidisc medium, this could be just the thing for you.

Looking Blank — Recording Media

There are currently two types of Minidisc available — the standard MD‑Audio, and the more recent MD‑Data. The first version is used in hi‑fi recorders to provide up to 74 minutes of dynamically assigned stereo recording time (or 148 minutes in mono), but it cannot be used for multitrack work. The MD‑Data disc, despite having the same 140Mb storage capacity, has a different TOC (Table Of Contents) area which stores details of each recorded section. There is no difference at all in data quality or data transfer rate, and physically the two types of disc look very similar.

When I interviewed the Japanese designers of Sony's MDMX4 4‑track Minidisc recorder, they also mentioned a new 650Mb format (see SOS March 1997), with 4.6 times the capacity of the other two discs, and this is what I originally suspected might be used with the MD8. However, this is not the case. The MD8 uses either MD‑Audio discs (for stereo or mono recordings) or MD‑Data, if you want to record in either 4‑track or 8‑track modes. The latter provides maximum recording times of 37 minutes with 4‑track, and 18 minutes with 8‑track. The current price for MD‑Data blanks from Yamaha is £18.79, which is reasonably in line with the cost of removable hard disk cartridges with a similar 140Mb capacity. However, the ATRAC compression system stores over 600Mb of audio data in this space, which makes the MD‑Data format a lot cheaper than it at first appears.

Brief Specification

RECORDER
Sampling Frequency: 44.1kHz
Frequency Response: 20Hz to 20kHz, +1, ‑3dB
THD + Noise: < 0.02% at 1kHz
Signal‑to‑Noise ratio: 96dB typical
Maximum recording times: 18 minutes with 8 tracks, 37 minutes with four tracks, 74 minutes with stereo, 148 minutes of mono

MIXER

Input sensitivity: ‑50dBu to ‑10dBu
EQ: +/‑15dB LF 80Hz shelving, Mid peaking (250Hz to 5kHz), 12kHz HF shelving
Output levels: ‑10dBu
Frequency Response: 20Hz to 20kHz +1, ‑3dB

Pros

  • Excellent recording quality, even after several bounces.
  • Twenty inputs at mixdown.
  • Lots of footswitch control options.
  • MMC implemented.

Cons

  • Imprecise level markings.
  • No digital I/O for mastering or backup.
  • No automatic bounce forward facility.

Summary

A compact but comprehensive 8‑track recording system, easy to integrate into a MIDI system, which would suit those who prefer not to have the sound of a whirring hard disk anywhere near their microphones.