MINIDISC: A BEGINNER'S GUIDE
by Bruce Bartlett
Introduced by Sony in 1991, the MiniDisc is a convenient
recording medium that is removable, low cost and near-CD quality.
This article will reveal the pros and cons of the MiniDisc
format, and will explain its features.
MINIDISC TECHNOLOGY
A blank MiniDisc is a rewritable, magneto-optical medium read
by a laser. The disc itself is like a miniature compact disc
inside a 2.5" square housing. A write-protect tab on the housing
prevents accidental erasure. Estimated disc life is 30 years,
but a strong magnet near the disc can erase data.
Two types of blank disc are available: the regular 74-minute
MiniDisc used in 2-track recorders, and the MD Data disc used in
multitrack recorders.
Most MiniDisc devices record audio at 44.1 kHz, 16 bits, but
24-bit recording is available in some units.
To fit all this data on a small disc, MD recorders use a data
compression scheme called ATRAC: Adaptive Transform Acoustic
Coding. It reduces by 5:1 the storage needed for digital audio.
ATRAC is a perceptual coding method, which omits data deemed
inaudible due to masking.
For example, if an audio signal has two sounds that are about
the same frequency, and one sound is louder than the other, the
quieter sound will be inaudible due to masking. So ATRAC removes
the quieter sound, which would be inaudible anyway.
ATRAC has had several revision levels; the latest version
(August 2000) is 4.5. The higher the version number, the better
the sound. Some reviewers have claimed that version 4.5 sounds
essentially the same as compact discs when playing a musical
program. Earlier versions are said to be near-CD in quality, and
much better than MP3. All versions are compatible.
Sound quality depends not only on the ATRAC version, but also
on the quality and bit depth of the A/D converter in the recorder.
There is a slight generation loss when tracks are copied or
bounced. The signal is ATRAC-processed with each copy. After
more than five copies or so, the sound cumulatively begins to
take on a mid-to-low rumble and a high-frequency squeak.
Minidisc recorders can make ATRAC-compressed copies of CDs
directly from the CD player's digital output.
MD vs. TAPE
Let's compare MiniDisc to other recording formats. MD
recorders are faster to work with than tape recorders. That's
because MiniDiscs (and hard drives) have random access: you can
instantly go to and play any part of the recorded program. In
contrast, a tape recorder is slower because its data is
sequential. You must fast-forward or rewind to the part you want
to hear. Another advantage of MD recorders is that they permit
non-destructive editing.
MD vs. MDM
How does a MiniDisc recorder compare to a Modular Digital
Multitrack recorder, such as the Alesis ADAT or TASCAM DA-88?
The MiniDisc's random-access offers instant locating of song
parts, instant non-destructive editing of tracks, and fewer
errors than tape. But MDM sounds very slightly better than MD
because the MDM does not compress the data.
Also, the MDM allows longer non-stop recording time, as shown
in the table below:
TASCAM DA-88........... 8 tracks 108 + minutes
140 MB MD Data disc.... 8 tracks 18.5 minutes
140 MB MD Data disc.... 4 tracks 37.0 minutes
160 MB 74-min. Minidisc 2 tracks 74.0 minutes
Iomega Jaz 2GB drive... 2 tracks 192.0 minutes
MD vs. HARD DISK
MiniDisc's main advantage over hard disk is that MD requires no
backup, but hard disk does. Suppose you want to stop working on
a multitrack project and start another. With a MiniDisc (or with
an MDM tape), it's easy: just remove the disc or tape and put in
a new one. In contrast, suppose you have a DAW or HD recorder of
limited hard-disk space. You must back up the old project on DAT
tape, CD-R or another drive; delete the old project, and start
the new project.
In a DAW you could change projects quickly by using a removable
hard drive -- such as an Iomega Jaz drive -- but MiniDiscs cost
much less. A Jaz 2GB disk costs about $99, while a MiniDisc
costs about $2. (The Jaz disk holds more data, though; see the
table above).
Hard disk wins over Minidisc in the area of editing. WAV files
stored on a hard disk can be edited in your computer; a
MiniDisc's ATRAC data file cannot. However, you can do simple
edits in the MD recorder itself.
We looked at some of the pros and cons of the MiniDisc
format. Now let's examine some actual Minidisc recorders.
TWO-TRACK MINIDISC RECORDERS
Sony MZ-R90
Two-track recorders come in portable style or component style.
The portable MiniDisc Walkman[tm] format is becoming popular with
news reporters who need to carry a small, high-quality recorder
in the field. Reporters can edit the recording using buttons on
the recorder.
Portable 2-track MD recorders have been used for documenting
musical groups at folk festivals. The recordist walks around the
festival, recording various groups of musicians (hopefully with
their permission!). MiniDisc also offers an easy way to record
school concerts, sound effects, or your band's gigs.
Can you use a 2-track MiniDisc to record a stereo master of
your mixdowns? You could, but CD-R and DAT masters are preferred
for their higher sound quality. Also, many mastering houses do
not accept MiniDisc masters.
MINIDISC MULTITRACK RECORDER
This device records and plays up to 8 audio tracks at once on
an MD Data disc. It lets you associate several virtual tracks,
or takes, with a single channel. Up to 8 tracks play at once,
but you can choose which virtual track (take) plays on each
track. For example, you can record several takes of a guitar
solo -- keeping each one -- and choose the best take during
mixdown. You also can create a composite track, which is made of
the best parts of several takes. Virtual tracks are also
featured in many HD recorders and DAWS.
MINIDISC RECORDER-MIXER
Yamaha MD8.
The MD multitrack recorder does not come in a standalone
format. Instead, it is built into an MD recorder-mixer. This
device is a mixer and multitrack MD recorder in a single,
affordable package. The built-in mixer has real faders and
knobs. There's a small LED or LCD screen for non-graphical
editing of the audio.
As we said, MD multitrack recorders use an MD Data disc, which
records 8 tracks for 18 minutes or 4 tracks for 37 minutes. MD
2-track recorders use a regular 74 minute MiniDisc.
MD recorder-mixers are great tools for tracking songs in a home
studio or project studio where the sound quality does not have to
be state-of-the-art.
Sony MDM-XR MKII
Compared to a cassette recorder-mixer, an MD recorder-mixer has
many advantages:
*Cleaner sound: no tape hiss, wow & flutter, or crosstalk. Much
less distortion.
*Instant access to any point in the recording. No waiting for
fast-forward and rewind.
*No open track needed for bouncing. You can bounce 4 tracks down
to 2 tracks on the same disc.
*Able to write disc titles and track titles.
*No need to clean heads.
*Less generation loss.
*More accurate recording timer.
*More durable medium.
*Tighter punch-ins.
*Jog/shuttle wheel.
*Markers (pointers) can be added.
*Cue list playback and Program Play List (explained later).
*Editing: Track and song copy/erase, song divide, song combine.
Let's go over editing in more detail. Song Copy duplicates a
song at a new location, while Track Copy copies data from one
track to another. Song Divide lets you divide a song in two at
the current counter location. With this function, you can create
sections -- verse, chorus, etc. -- that you can play or repeat in
any order. You can also remove noises before and after songs.
Song Combine joins divided parts from the same song. Some units
let you move individual tracks in time.
The Cue List feature is a list of the song sections in the
order you want them played. Sections can be looped or repeated.
The recorder will play down the cue list, assembling the song
from its sections. A Program Play List is a list of the songs in
the order you want them played.
Scale Factor Edit can be used to match the volume of tracks
recorded at different levels, or to create fade-ins and
fade-outs.
All units offer an output for MIDI Time Code or MIDI Clock, in
order to sync the MD to an external MIDI sequencer.
MiniDisc is one of many digital formats to choose from. It
offers fast access, editing, near-CD sound quality, and low cost.
No data backup is needed. If those features are important to
you, MiniDisc might become your favorite format.
For more detailed information, I highly recommend the web site
http://www.minidisc.org
© 2000 Cassette House
May not be reproduced in whole or part without permission.
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