They had problems in the begining when they first started selling them. Y'see, in '92 Sony was targeting them to the 'MTV' generation; And said generation wanted them, but no one who spends all waking hours watching MTV can afford to drop $400 USD on a glorified tape deck. So the rebirth came in the late 90's, after Sony Improved the audio quality a lot, this time going after rich kids with loaded parents.

MiniDisc is a relatively new audio recording technology from Sony which, IMHO, combines the best parts of CDs and tapes. It's digital, which means that it retains the quality of CDs, as well as being indexable by track, just like CDs, but is also re-recordable, like tapes, making them extremely useful. They hold 74 minutes of music (or double that if you don't care and want to record in mono, rather than stereo), just like a CD, but measure only roughly 2.5 inches square. The physical medium itself also comes within a plastic case which you insert into the player. This case protects the disk from shaking around too much, which cuts down on skipping while running, etc.

As of yet, not many albums have been released to MD, but buying CDs then transferring them to MD is easy. You can also take the audio out from your computer and thereby record MP3s that you have onto MD. The recording device is quite smart and interprets breaks in sound as intended track breaks. The most expensive portable player/recorder on the market right now is about US$250 and MiniDisks themselves cost about US$3 each. Yeah, that's expensive per disk, but remember they're re-recordable and that price will almost certainly drop if the format catches on.

The most recent MD players and recorders can also use a new format, usually referred to as MDLP or MDLP 4. Basically, it encodes the sound more efficiently, so that (without losing quality) you get 4x the play time per MD. So an 80 minute MD gives 320 minutes of play time. That's five hours and twenty minutes on one disc. I currently have six blank 74 minute discs and two blank 80s, which, using MDLP, gives me a total of 2,416 minutes of recordable time, in perfect quality (barring degradation from my recording setup, which should be minimal since it's optical). That's 40 hours and 16 minutes, using only eight tiny discs.

I think I'm in love.

Currently (2000/01/10), there are only two portable MD recorders which support MDLP 4, afaik, both of which are Japanese imports (i.e. no North American versions yet, but they can be obtained easily from online vendors):

Hopefully, this node will soon evolve to detail most MD equipment that supports playing/recording MDLP 4.

There are two features which make the Sony MiniDisc uniquely different from both CDs and tape.

First, it uses ATRAC compression. Using the same basic techniques as MP3 compression, ATRAC removes the frequencies most people wouldn't hear anyways and then compresses the rest. This is what makes it possible to record a whole CD worth of music in one-quarter the space. However, it also ensures that MiniDiscs will never be a replacement for CDs or DAT so long as some people want or need high-quality, uncompressed audio.

Second, it uses a table of contents. This is an advantage over both CDs and tape because it lets the owner edit a MiniDisc quickly without re-recording. Want to delete a track in the middle of your mix? It's gone in a second. Want to rearrange the order of your tracks? That's just as easily done. Once the music is recorded on the MiniDisc, it can be reorganized and rearranged just as easily as the directories on your computer's hard drive.

Magneto-optical playback

On a Compact Disc, data are represented by microscopic holes on the disc surface. The data are then read back by a laser. Since the rearranging of holes on a Compact Disc surface requires physical alteration of the material, re-recording a CD causes the medium to degrade quickly. With the MD, Sony aimed for a digital music format that could easily be re-recorded many times over without quality loss. Therefore, Minidisc had to employ a very clever alternative to the land-and-pit scheme of the CD.

On Minidiscs, data are represented by magnetic charges instead of lands and pits. A polarized laser is then used to read the data. In polarized light, all waves are in a single three-dimensional plane. When a polarized beam hits a magnetic surface, the polarity of the light changes on reflection: the lightwaves will be in a different plane.

Exactly how the polarity changes depends on the polarity of the magnetic surface. Thus, a laserbeam reflecting from a positively charged surface will have different polarity than a beam reflecting from a negatively charged surface. If you use special Polaroid 'glasses' that are aligned with, say, the positive reflections, you would only be able to see the light if the reflective surface is positively charged. This way, you can 'see' the polarity of the reflective surface.

Magneto-optical recording

In order to use the phenomenon described above to store data on the Minidisc, a technique is required to give very small parts of the Minidisc surface a specific magnetic charge. There are two ways of doing this. Both are based on the fact that any potentially magnetic material will instantly take over a surrounding magnetic charge when the material is heated to its Curie point.

A Minidisc recorder contains a crude electromagnetic coil that can put either a positive or a negative magnetic field around a part of the Minidisc. The disc surface is made of a material that is not easily magnetized. When the recording laser heats a small area on the disc, it will take the magnetic polarity of the coil.

A disc surface can first be charged negatively. Then the coil can be set to produce a positive magnetic field and the laser can be used to heat up all the desired areas on the disc to their Curie point. These areas will then have a positive charge and the data can be represented conveniently.

Another way of doing it is by keeping the laser hot and directing it past all sequential surface areas. The field direction of the magnetic coil can then be modulated above certain areas to produce the desired charge. This method is a bit harder to realise because it requires a more delicate coil. The magnetic field direction of a coil is more difficult to modulate than the amplitude of a laser. One serious benefit is that a surface can be re-recorded in one go. It doesn't need to be reset to an all-negative starting position.

Minidisc was released by Gescom in 1998 on Or as catalogue number ONLY3. The tracklist is as follows:

  1. Cut Begin (0:14)
  2. [untitled - #2] (0:10)
  3. [untitled - #3] (0:13)
  4. [untitled - #4] (0:07)
  5. [untitled - #5] (0:12)
  6. [untitled - #6] (0:15)
  7. [untitled - #7] (0:20)
  8. Amendment 84 (1:05)
  9. Helix Shatterproof (1:06)
  10. A Newer Beginning (0:18)
  11. [untitled - #11] (1:08)
  12. Polarized Beam Splitter (0:37)
  13. [untitled - #13] (0:08)
  14. [untitled - #14] (0:42)
  15. [untitled - #15] (1:19)
  16. [untitled - #16] (0:22)
  17. Inter (2:40)
  18. R M I Corporate ID 1 (0:08)
  19. Pricks (0:23)
  20. [untitled - #20] (3:55)
  21. [untitled - #21] (0:23)
  22. [untitled - #22] (0:06)
  23. Devil (0:29)
  24. Is We (3:07)
  25. [untitled - #25] (0:51)
  26. Dan Dan Dan (0:26)
  27. [untitled - #27] (0:14)
  28. [untitled - #28] (0:14)
  29. [untitled - #29] (0:15)
  30. Le Shark (0:04)
  31. [untitled - #31] (0:04)
  32. [untitled - #32] (0:06)
  33. [untitled - #33] (0:06)
  34. [untitled - #34] (0:11)
  35. [untitled - #35] (0:17)
  36. [untitled - #36] (0:15)
  37. Shapethrower (2:12)
  38. Shoegazer (4:12)
  39. Vermin (0:13)
  40. [untitled - #40] (0:47)
  41. [untitled - #41] (0:13)
  42. Hemaplegia 1 (1:04)
  43. MCDCC (1:01)
  44. Gortex (0:23)
  45. Alf Sprey (0:13)
  46. Interchangeable World (0:09)
  47. [untitled - #47] (0:32)
  48. [untitled - #48] (1:17)
  49. Cranusberg (0:48)
  50. [untitled - #50] (4:14)
  51. [untitled - #51] (2:55)
  52. Raindance (0:37)
  53. Horse (0:04)
  54. New Contact Lens (1:29)
  55. Of Our Time (1:46)
  56. Crepe (0:04)
  57. [untitled - #57] (0:27)
  58. [untitled - #58] (0:04)
  59. [untitled - #59] (0:22)
  60. Wab Wat (0:49)
  61. 'MC (0:13)
  62. Peel (1:02)
  63. I G E (0:08)
  64. Knutsford Services (0:57)
  65. Fully (2:24)
  66. [untitled - #66] (1:45)
  67. Squashed To Pureness (0:08)
  68. [untitled - #68] (0:15)
  69. [untitled - #69] (0:10)
  70. [untitled - #70] (0:48)
  71. Yo! DMX Crew (2:47)
  72. Go On (1:36)
  73. Stroyer 2 (0:20)
  74. [`nothing'] (1:05)
  75. [untitled - #75] (0:09)
  76. Shep (1:07)
  77. Langue (0:08)
  78. Poke (0:09)
  79. [untitled - #79] (0:15)
  80. [untitled - #80] (0:30)
  81. [untitled - #81] (0:13)
  82. Hemiplegia 2 (0:16)
  83. Territory Of Usage (0:17)
  84. [untitled - #84] (0:36)
  85. Tomo (0:15)
  86. [untitled - #86] (0:16)
  87. R M I Corporate ID 2 (0:07)
  88. PT/AE (0:06)

As you can see, most of the tracks are very short, and the interesting thing about this release is that you are to hit shuffle on your player, and thus listen to an ever-changing song, that will evolve as time passes. Alternatively, you can program it to be the way you want, mixing the percussion tracks with the melody tracks.

Minidisc was reissued in 2001, with a black cover, as opposed to the white cover that was on the first edition. The cover itself is entirely in one color, with Gescom in the lower part.

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