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A format too far?

DCC vs. MiniDisc

Article from The Mix, January 1995

Is either format any good?



The problem with digital technology is that so little of it speaks the same language... or is for that matter in the same format or storage medium.

With computers, floppy disks can be interchanged and software used to allow totally different types of computer to exchange information. But when it comes to two-track digital recorders, the variety of choice out there impresses feelings of isolation rather than community.

You could have an open reel digital recorder, but it'll either use Sony's DASH format or Mitsubishi's ProDigi system. If you want to move into a cassette-based medium, then you can look back ten years to Sony's PCM F-1 system, which stored digital audio information on adapted Betamax video recorders (see Home & Studio Recording December 1983). U-Matic video machines too, play their part in audio mastering, yet the factor that makes all these systems beyond the grasp of the masses is cost.

But what about DAT? What about it indeed. People are hardly queuing up to buy them at Dixons. DAT works — ask anyone who's got one — but again there's a price to be paid. Basically, there are two types of DAT recorder you can buy: Either a so-called consumer DAT, or a professional machine. Consumer DATs cost around £400 or more, while the pro DATs are at least double that. At those prices, is it any wonder that DAT hasn't broken through to the domestic market?

Formats


So what else is there? As far as tape-based systems go, there's the Digital Compact Cassette (DCC) from Philips. DCC is unique, because even 'though it uses a new type of cassette for digital recordings, it can also play your old analog compact cassettes. There's no special caddy, you just put in either type of cassette and the machine will play it. At present you can't record onto the conventional analog cassettes, these are playback only, but the machines do offer Dolby noise reduction if you use it. Marantz support DCC, as do Technics, who are working on a model that will record on both cassette formats, which should be very interesting.

If you're uncertain about the future of tape, then Sony's MiniDisc is designed to appeal to you. The MiniDisc is unique too, but because of its entirely different storage medium. Pre-recorded MiniDisc material cannot be erased. It's more or less a mini CD only 2.5" in diameter. However, you can buy recordable MO (magneto-optical) discs that can be re-recorded again and again. All you need is a MiniDisc recorder.

Sony MZ-R2 Portable MD Recorder



The Sony MiniDisc MZ-R2 is about the same size as your average Walkman, but pick it up and you can soon spot the difference. At just under 3/4lb. it's a reassuringly weighty package. Most of its functions operate like those of a CD machine, but at the front is a sliding record switch, enabled by a recessed centre button. A small red LED indicator not only shows you're in record, but dims with increasing input level. Another slider opens the lid — only wide enough to perform disc changes — making the process virtually tamperproof, as well as protecting the laser lens and transport mechanisms.

Below the open slider is the Hold switch. This freezes the controls so that they can't be altered. This comes in handy if you're recording on the move. As there's no power switch on this machine — pressing a transport control activates it — you might want to use Hold while the machine is in Stop, so that it doesn't get activated accidentally and waste battery power. The headphone socket is a typical 3.5mm stereo mini-jack, but with a spur which facilitates full-function in-line remote control from the headphones.

Along the left side of the MZ-R2 lies the rechargeable battery compartment, a three-level bass boost switch, and three mini-jacks providing access for line out, line/optical in and mic input. The line input doubles as an optical input for digital transfers, so that you can record CDs directly to the MiniDisc down an optical cable, but unfortunately not back the same way; there is no optical output. At the rear is the 6VDC input. Or you can screw the auxiliary battery pack (3 x AA batteries) onto the back of the MZ-R2.

Finally, hiding under the lid of the MZ-R2 is a sliding metal plate with three small buttons calling for highly manicured nails (or a handy pencil). Their function can involve destructive edits on recordable MiniDiscs.

Track Mark allows you to put inaudible markers onto existing recordings. You could break up a song into numerous track markers for verses and choruses. All subsequent tracks are automatically incremented. End Search finds the end of the last recorded track on the disc, so that you can record from there onwards. Erase will irretrievably destroy a track. Tracks either side of it will be unaffected and will play continuously, as if the erased track had never existed. You don't get any lengthy gaps where the old recording was, and following tracks are renumbered appropriately.

In Use


Once you slot in the state-of-the-art Lithium-Ion rechargeable battery, the manual urges you to set the clock. The MZ-R2 adopts a computer style approach to many of its disc functions, as setting the date and time allows the MiniDisc to keep a record of when you've made your recordings.

Prodding the Display button to the right of the LCD screen scrolls through any track data on the MiniDisc. If it's pre-recorded, then album title/artist and track name scurry across the screen. Total playing time appears as soon as you put in the disc, but after that you can only view track lengths and elapsed time. Using a recordable disc, the display tells you how much recording time is available, and using the search/AMS keys to move through the tracks CD style, you can view the date and time info of each track as well as its total length.

A variety of playback choices are accessed from the Play mode button beneath the Display one. As well as normal playback, you can repeat all tracks, repeat just one, or try out Shuffle for a random track order. Once again, the display indicates where you're at.

Being able to repeat one track is perhaps the single most useful feature of the MZ-R2 as far as musicians are concerned. If you've got a song to learn, you can record it onto MiniDisc and set up track marks for intro, verse and chorus. Simply play the track and put them in where you want. You can then cycle around these markers without having to wait for the tape to rewind.

It's not completely seamless, there is a fractional pause, so making perfect beatloops on the fly is not really possible. However, having musical sections repeat endlessly makes for very easy sampling. And you can also use track markers to find points that you want to erase. Chopping off a hissy or crackly lead-in to a song, or even editing umms and arrs in speech recording. Radio journalists could perform elementary edits of interviews while on the job. As this is a destructive process, you must be absolutely sure that you've cued up the right sections to erase. You could end up with ums and arrs and no interview!

Recording on the MZ-R2 is assisted by the End Search function, which locates the end of the last recorded track. This is actually a bigger deal than it might sound, because of the destructive nature of MiniDisc recording. I'm sure most of you have at some point accidentally recorded over a track you wanted to keep, but luckily rescued it before too much damage was done. With the MiniDisc, as soon as you start recording, all tracks from that point on will be erased. You can't insert a track, you must find the end of the last track you want to keep, or you've had it! Bearing in mind that unwanted tracks can be erased, it's still quite easy to keep things tidy on your disc.

Performance


Audiophiles weren't too impressed with the early MiniDisc models, and for their price you'd expect something special. Sony's latest, the MZ-R2, does sound good. Not spectacular, but not bad either.

The bass boost (headphones only) increases noise considerably, and although a popular feature for many, I avoided it. An option for treble boost or a graphic eq would win my vote, as I found the top end lacked presence and the middle frequencies were coloured slightly, losing some definition.

The digital input came in handy so that I could record CDs directly to the MZ-R2 for comparison. You can opt for AGC (automatic gain control) on mic and line inputs, to set the record level for you. This is useful for difficult environments, but background noise increases when the AGC adjusts to fading signals. Holding the record slider in place for a couple of seconds switches the MZ-R2 to manual record, the transport keys doubling as level controls while in pause. But once you start manual recording, you can't change record level or monitoring volume. They can only be altered in standby, which is a drag.

Recording is virtually instantaneous, while track selection takes two seconds at the very most. As you can imagine, it's not difficult to get to like the MZ-R2, as everything is so quick. Play back what you've recorded straight away, then use End Search to continue recording without worrying about over-recording anything.

Testing the mic input. I used the recommended Sony ECM-909A stereo microphone, but it also worked with a stereo tie-clip mic from my Toshiba recording Walkman. Retailing at around £70, the ECM-909A is not exactly hi-fi and is a touch noisy itself, but performs well enough to be worth considering.

The end result with this set-up is a rather cold sound, tending to sizzle at the top end, losing some warmth in the process. The AGC handled transients well, but its action was rather obvious, as room ambience waved in and out with changing levels. Naturally, manual recording didn't suffer those sorts of problems, but being a digital system, you do have to set your levels carefully to avoid input overload from erroneous sounds.


Philips DCC 170 Portable Recorder



If you ever saw Philips's first flagship model the DCC 900, you'll find it hard to believe that the DCC 170 is from the same family. David and Goliath springs to mind.

At 9kg the DCC 900 was certainly built to last, while at less than half a kilogram the DCC 170 has been constructed for versatility rather than robustness. Slide the Open button across, and the lid pops up slightly. You can then open it up till it clicks in place at around seventy-five degrees. Underneath the bonnet is the rechargeable battery compartment. A Nickel-Cadmium battery slots in here and is covered up with a detachable plastic lid.

Further inside, two familiar cassette-style drive cogs, and a warning message against the use of conventional analog tape demagnetisers. Unlike their in-car DCCs, the DCC170 doesn't come with a suitable non-magnetic cleaning tape. What you do get is a generous allocation of five 90 minute digital tapes, worth about £25.

Right at the back is the DCC's purple tape head, with a capstan and pinch roller on either side. This is after all, an autoreverse deck. Unlike DAT recorders that have videostyle rotary tape heads, the DCC employs stationary heads, similar in concept to those used on digital multitracks; applying 'thin film technology' to cram 36 channels onto one head.

DCC hi-fi separates have only half that number, as the heads flip over when the tape direction changes. The other side of the head has conventional analogue playback heads, to perform the same functions on an analogue compact cassette (or ACC in Philips-speak). As well it might, for Philips invented them too!

On the DCC 170 the heads are permanently mounted, so there are two sets of nine 'Integrated Recording Heads' (IRHs) for recording, and nine 'Magneto-Resistive Heads' (you guessed it, MRHs) for playback. So the digital playback heads are also used for ACCs.

Attached to the underside of the lid are thin metal guides that ferry the cassette format of your choice towards the tape heads. The lid itself is lightweight, and feels a little vulnerable when opened. Snapping it shut, the machine waits for further instructions, as there is no power switch. Prod a transport button and the DCC writes 'Power On' across the LCD screen, has a quick think while briefly playing the tape for positional and text info, then carries out your instructions.

Below the LCD are buttons for time display, text and track mark options. The time display shows absolute time, elapsed track time, remaining track time and total time. The last two modes only work for pre-recorded DCCs, as does the Text function. Mode creates automatic track markers when the digital input is used, or line input when gaps are longer than three seconds. Mode can be switched off, and markers created manually with the Write function key. When used with a microphone, automatic marking is disabled, so track marking has to be done manually.

Beneath these function keys are the recessed chrome transport controls, while autoreverse mode, Dolby B Noise reduction on/off (ACC only) and Dynamic Bass Boost (DBB) are controlled by switches on the DCC170's left side. A modified 3.5mm stereo jack once again controls headphone output, its extra ring allowing transport communication (including record) from the lightweight clip-on 'phones.

Over on the right side is the hold switch which, like the Sony MiniDisc, prevents the controls from being altered from their current status. A three-way switch selects microphone levels high or low (-20dB) and line level. Record mode allows you to choose ALC (for automatic level control) or manual recording, adjusted by the adjacent rotary record level knob. Another 3.5mm jack socket takes care of all three input sources: mic, line and digital.

Philips supply a coaxial-to-jack digital cable, so that you can record digitally from a suitably equipped CD player, DAT machine, fellow DCC or perhaps a MiniDisc, but not the MZ-R2, as it has no digital out. Fortunately, Philips have included a digital output on the DCC 170, which really does expand its horizons significantly, especially if you're in the market for squeaky-clean samples, digital editing or just plain tape cloning.

At the back of the machine, next to the 6VDC input is the line out and digital out. Again, both come out of the same mini-jack, but this time, the digital protocol is optical. The digital interfaces only work when you're plugged into the mains. All DCC recorders will accept a digital input at all three popular sample rates (32, 44.1 & 48kHz) which is good news for anyone who wants to transfer a DAT collection to DCC. DCC's ability to handle any sampling rate you can throw at it might even precipitate a glut of second-hand DAT machines!

In Use


If you plop in a blank DCC cassette — to be sure that the machine writes absolute time on the tape — you must rewind it first. This is a precautionary measure that DAT owners will be familiar with. Slide into record pause, and the machine displays 'Lead In', as it positions itself to the start of the tape. Another message appears showing the selected input and sample rate. DCCs select 44.1kHz by default, but change automatically to the rate of external digital sources. Hence, a DAT tape with different sample rates can be copied easily.

Now you're in record ready, press Play and the DCC writes a track marker while recording, and notches up absolute time. The LCD metering concentrates over a range of -30dB to 0dB marked in 6dB increments, but unlike its larger DCC siblings it doesn't display playback levels of analog tapes. After a recording, when Stop is depressed, the DCC writes an End marker, which will appear in the display when it is reached during playback, so you can identify the end of a group of recordings and continue recording from thereon if desired.

DCC tapes use both sides of the cassette but you don't turn the tape over. You can decide whether the recording will continue on side B or stop. You can't record on side B and then continue on side A without telling the machine to do it yourself. This is just as well, as you could start recording and then erasing earlier stuff on the same tape, while looping round endlessly.

Pressing the Play button toggles the selection of the side to play or record on. The LCD keeps you up to date, and once playing you can quickly swop sides. With pre-recorded tapes, the sides change over so quickly that with headphones on, you don't even notice the brief click of the mechanism changing direction. This can also be achieved with homemade recordings, using one of two special markers: Reverse and Next. With Reverse, you can mark the end of the last track on side A, to autoreverse and continue to play back on side B. Alternatively, you could mark the same track to instruct the machine to wind to the end of side A, and begin playing from the start of side B. Both markers are very useful, and enable 'handsfree' continuous playback.

If you're playing back a pre-recorded DCC, then track searching is a doddle. There's no way the system can match the speed of CD or MiniDisc, but tracks can be located easily as the LCD shows their names as you scroll through the search/wind keys while in play mode. The same is true with user DCC recordings, but only track numbers are available. Initiating a track search can at first appear confusing.

The DCC 170 plays a bit of the tape to itself, and then searches. As you may be wanting to rewind, seeing the counter go forward is surprising. The reason for this is so the machine can calculate the quickest way to get to the track, by choosing an appropriate wind speed. In order to improve access times, the motor can gear up through three different speeds.

Performance


So Philips have produced an 18-bit, portable DCC for 250 quid. Sounds too good to be true, doesn't it? Nevertheless it's here, and the lessons of price and consumer willingness to invest in a new format seem to have been well and truly learned by their marketing team. The major record companies have already given the format a vote of confidence with pre-recorded tapes.

Using the digital input, digital transfers from CDs for reproduction comparisons were possible. In this test the DCC 170 scored highly, retaining the original presence and detail of the mid-range. Stereo width was good too, and listening on headphones, the bass boost worked well with no significant increase in noise.

When recording with the line input, using manual level control was definitely preferable to the ALC. The ALC seemed a little nervous about high levels or booming bass, with a tendency to overcompensate; dipping out in level before returning to the previous norm. While the line input circuitry was clean and healthy, unfortunately the same could not be said of the mic input. During quiet passages, the hiss from this input was evident in both high and low gain modes.

Naturally, with louder source material this shortcoming would be less obvious. So anyone with a penchant for taping gigs or loud sound effects wouldn't be bothered. But if it's the distant mating call of the lesser spotted toad that you're after, then forget it. Nevertheless, you can't ignore the fact that this is a portable digital recorder at a previously unheard of price, and any serious miking would be better served using an external mixer and the line input. Make sure you've switched it to line and not mic, as the DCC 170 uses the same input for both.

Last but not least, is the appealing ability of the DCC system to play existing analogue tapes or ACCs. ACCs have their shortcomings, but the DCC 170 brings out the best in any tape. Automatically switching to normal, chrome or metal, high frequencies penetrate clearly without the premium of additional hiss, while bass and mid-range are respectably held in check. Even the Dolby B is well adjusted, and prerecorded tapes (virtually all are mastered with Dolby B) sounded silent rather than suffocated. Analog cassette playback is also sent to the digital output, which can make life easier for copying, sampling or hooking up to a digital amp.

The essentials...

Sony MZ-R2
Price inc VAT: £349.99
MiniDisc 74 minute discs approx £11.00
More from: All Sony stockists/Sony Customer Information Centre (Contact Details)

Philips DCC170
Price inc VAT: £249.99
DCC 90 minute tapes approx. £5.00
More from: Philips Consumer Electronics, (Contact Details)


How Do They Do It?

PASC & ATRAC
Both Sony and Philips use similar methods to get phenomenal amounts of data onto relatively small storage mediums. A process involving psycho-acoustic techniques modelled on the response of human hearing is employed. It's called noise shaping, and both companies have different systems and models to achieve the same ends.

Incoming signals are examined, and complex calculations are performed to determine what sounds are actually audible. So rather than record everything as DATs do, only the audible signals are encoded, and sounds that are masked by louder music are left out. This significantly reduces the amount of data that needs to be stored.

Hence, Sony can get 74 minutes of 16-bit stereo sound onto a 2.5" disc, and Philips can use both sides of a tape that's the same width as a standard cassette to store up to 105 minutes of 18-bit digital stereo.

Philips call their system PASC (Precision Adaptive SubCoding) which has a slightly different frequency response to Sony's ATRAC (Adaptive Transform Acoustic Coupling).

It's the way these algorithms perform that is going to keep the hi-fi buffs in beer and sandwiches, as they argue the merits of these systems in the years to come. Soon there'll be opportunities for you to do the same, as music stores are set to have listening posts so that you can decide whether Philips have it taped or Sony has the disc of the day.


Spec check

Sony MZ-R2
Coding: Adaptive Transform Acoustic Coupling
Frequency Response: 20Hz to 20kHz +/- 1dB
Sampling Frequency: 44.1kHz
AD/DA conversion: Unspecified. Pulse D/A converter
Dynamic Range 105dB
S/N ratio: Unspecified
Inputs: Microphone, Line In (both via Stereo mini-jack) Digital (Optical mini-jack via Line in socket)
Outputs: Headphones, Line out (stereo mini-jacks)
Power Requirements: Rechargeable Lithium-ion battery pack (LIP-12) or three AA batteries. Mains adaptor 6VDC psu.
Battery operation time: 120mins consecutive recording or 150 mins of consecutive play-back with fully charged LIP-12.
Dimensions: 84 x 29.9 x 106.8mm (w/h/d)
Weight: 310g including rechargeable battery.

Philips DCC 170
Coding: Precision Adaptive Sub Coding (PASO)
Frequency Response: 20Hz to 22kHz +0.5dB/-1.5dB@ 48kHz 20Hz to 20kHz +0.5dB/-1.5dB@ 44.1kHz 20Hz to 14.5kHz +0.5dB/-1.5dB @ 32kHz
Sampling Frequency: 48kHz, 44.1kHz & 32kHz (selected automatically)
AD/DA conversion: 18-bit linear bitstream converters
Dynamic Range: >108dB
S/N ratio: >92dB
Compact Cassette Frequency Range: 20Hz to 18kHz
S/N ratio (CrO2): >50dB (Dolby NR Off)
Inputs: Microphone, Line In (via Stereo mini-jack) Digital (via supplied coax to mini-jack cable into Line/Mic in socket)
Outputs: Headphones, Line out (stereo mini-jacks) Digital (Optical mini-jack)
Power Requirements: Rechargeable Nickel-Cadmium (SBC 6434) Mains adaptor 6VDC psu
Battery operationtime 180mins consecutive recording or playback with fully charged SBC6434
Dimensions: 111.6 x 38.1 x 99.8mm
Weight: 420g including rechargeable battery.


Juke box jury

As tastes vary from person to person, I invited several people to listen to both the MiniDisc MZ-R2 and the DCC 170. Digital transfers of recordings to both formats were played back, and 'blindfold' listening tests were carried out using four different-sized speakers in different environments.

It has to be said that it was pretty close, but the DCC 170 seemed to win the day. Words such as 'spacey', 'airy' and 'more exciting' were used to describe the DCC 170 sound, and the MZ-R2 did seem to lose some of the recordings' ambience and presence. On smaller speakers, the detail of sparkling percussion appeared more defined on the DCC.

For digital and line inputs, the Sony seemed to produce a mid-range resonance that coloured its sound, which may have been responsible for a perceived loss of warmth in the bass. However, the mid range appeared kinder for the microphone tests, although the stereo image was narrower and the bass fainter than the DCC.

Although the Sony MZ-R2 does have a better mic input, it lacks a digital out, which is something I feel should be mandatory on all new digital recorders. The MZ-R2 will only accept 44.1kHz through its optical digital input, which is another shortcoming, especially if you'd hoped to use it with the digital output from a digital mixer, or for copying from a consumer DAT. Coaxial outs and 48kHz are the norm in this realm. The DCC 170 is better suited for such applications, with its coaxial input and multiple sample rate capability.

Unsurprisingly, the hi-fi separates from both manufacturers have more functions. Sony's MDS 501 has an optical digital output and built-in sample rate converter, accepting 32, 44.1 and 48kHz. It also has an £800 price tag! Meanwhile, old models of Marantz and Philips DCC decks are being sold off for less than £200, and the new DCC 730 due in February will sell for around £350 and has both optical and coaxial digital inputs, 18-bit recording/play-back, Turbo Drive tape mechanism and Dolby B & C for ACCs. 18-bit tapes are already available, and as interested Japanese manufacturers produce their own versions of MD and DCC, it would seem that these are sound beginnings.

As for appeal, the MiniDisc MZ-R2 is certainly fast, and its ability to instantly loop round points of your choice will win the hearts of many a muso, learning or transcribing songs. The sound quality shortcomings are only likely to bother the most exacting ears.

The DCC 170, on the other hand, is a true Walkman in every sense of the word. To say it's a new format is completely true, but the fact that it supports the conventional compact cassette broadens the appeal of the system considerably. There are many out there that would prefer to wave goodbye to the idea of using tape, but at the moment it would appear that you have to pay for the privilege and sacrifice the opportunity for 18-bit recording.



Previous Article in this issue

Mixing It! USA

Next article in this issue

Inner tube


Publisher: The Mix - Music Maker Publications (UK), Future Publishing.

The current copyright owner/s of this content may differ from the originally published copyright notice.
More details on copyright ownership...

 

The Mix - Jan 1995

Donated by: Colin Potter, Chris Moore

Coverdisc: Mike Gorman

Control Room

Review by Bob Dormon

Previous article in this issue:

> Mixing It! USA

Next article in this issue:

> Inner tube


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