MiniDisc gains popularity Sound: They can record and play back, and the technology is getting less expensive

September 14, 1998|By Sean Gallagher | Sean Gallagher,SPECIAL TO THE SUN

On a recent cross-country flight, I threw a pile of my favorite CDs into a travel bag along with a portable CD player. As I tried to gently place a disc into the player while balancing my complimentary peanuts, the disc and its jewel case fell onto the floor. Twisting and ducking, I grabbed the disc before it was stepped on - but the jewel case was crushed by the flight attendant's snack cart.

These are the hazards of the traveling music lover. You either carry a stack of CDs and put them in harm's way - and deal with the jumps as you go over bumps - or record your favorite tracks onto audio cassette tapes and put up with static and a locked-down soundtrack.

Now there's a better way - the digital MiniDisc. It's a happy medium between the audio quality and random access of CDs, and the portability and recording capacity of cassette tapes. While MiniDisc technology has been available for years - Sony introduced the format in 1992 - it is finally being accepted by audio component manufacturers.

As a result, the MiniDisc is becoming more affordable. While Sony is still the biggest manufacturer of MiniDisc systems, companies such as Sharp Electronics, Kenwood and Yamaha are building a variety of MiniDisc recorders and players. Even the discs themselves are getting cheaper. Sixty-minute and 74-minute blank MDs sell for $4 and $5 - comparable to the cost of a high-quality audio tape.

I ventured into the world of MiniDisc technology with the aid of a Sony DHC-MD515 bookshelf mini-system and a Sony MZ-R50 MD Walkman. The $700 bookshelf unit has two changers that hold 3 MiniDiscs and 3 CDs. It also has a remote control. The MD Walkman sells for about $350.

For those who have a stereo component system, Sony sells MD player-recorder components in the $300 range, and automotive MD units for just slightly more. Products from other manufacturers are similarly priced.

While they're still more expensive than compact disc players, you can expect the prices to fall even further over the next year. Even now, compared to other digital recording formats such as recordable CDs (CD-Rs) and digital audio tape - MiniDiscs are competitive.

MiniDiscs can store up to 74 minutes of stereo audio - an entire, typical-length CD album - on a 2 1/2- half inch, plastic-encased disc. You can play the tracks in any order, and add and delete individual tracks at will.

Prerecorded MiniDiscs are based on the same technology as CDs - there's no way to record over them, as the tracks are permanently etched into the disc. Recordable MDs use technology similar to recordable CDs. They use a coating that can be recorded and erased by using a combination of a laser and a magnetic head, and can be played back by being scanned by a laser - just like plain old CDs.

Just how does all that music get into such a small package? The short answer is that not all of it gets there. MiniDiscs use ATRAC (Adaptive Transform Acoustic Coding), a compression method that drops frequencies above and below the normal range of human hearing, along with background audio that is "masked" by louder sounds. As a result, MiniDiscs store only one-fifth as much information for each audio track as a CD.

Some audiophiles complain that these compression tricks reduce the quality of the playback, but the real difference depends on what kind of music you're listening to - and the version of ATRAC technology that was used to record the disc.

Using standard CDs as my source, I recorded and re-recorded a mix of musical genres on MiniDiscs to put them through the audio grinder. Even after deleting and adding tracks to the MiniDiscs repeatedly, I couldn't detect any difference between the smaller discs and the CDs from which they were recorded.

The best way to record a MiniDisc is with a direct digital connection to the source. Many new CD players have a digital output jack which allows you to record from the CD without the electrical noise that occurs with a standard headphone or patch cord.

Digital recording also provides recording companies with some level of protection - the ATRAC coding standard automatically copy-protects a digital MD recording so that it can't be used to create additional digital recordings. To reproduce a CD with the highest level of accuracy, you must have the original.

ATRAC 4.5, the latest incarnation of the coding scheme and the one used in most new MD player-recorders, is much more efficient than its predecessors and captures a greater range of frequencies. Music recorded with older equipment will play on new equipment, but may not sound as good. And even the latest and greatest MiniDisc equipment may not stand up to the demands of some audiophiles.

Since it has to read less information than a standard CD, a MiniDisc player can "read" a tune faster than a CD player and store more information in its temporary memory, or buffer. CD players of all types use buffering (storing a few seconds of music in advance) to help reduce skipping caused by bumps and jostles.

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