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

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 Deltamedia

May not be reproduced in whole or part without permission.