A sony minidisc

The Gadget We Miss: The Sony MiniDisc

Sony’s pioneering music format failed to catch on, but found a few unexpected niches

Richard Baguley
Published in
8 min readSep 27, 2013


Most gadgets don’t have a funeral. The closest they get is a small note on a web site saying that the manufacturer is no longer supporting it, or a final post in an obscure fan forum from a last, desperate fan. The MiniDisc format had a slightly better send-off: in February of 2013, Sony announced that they would no longer be making MiniDisc players. This effectively marks the end of a 21-odd year lifespan for this unusual take on the perennial problem of how to make music portable, but still sound good.

Sony MiniDisc advert, undated / Herby Hönigsperger

The MiniDisc format began as a research project in the labs of electronics giant Sony in the early 1990s. In those pre-iPod, pre-flash memory days, engineers were struggling with the problem of how to make music portable. Sony was riding high on the success of their Walkman players, which had come to dominate the market in the 1980s. But they were bumping up against the limits of the media: both cassette tape and CD Walkman devices really couldn’t get any smaller, because the medium itself was the limiting factor. Devices like the cassette tape Walkman WM-EX88 and the CD D-J50 were not much bigger than the cases that the cassette tape and CD were stored in: they literally couldn’t get much smaller and still hold the tape or CD. What was needed, Sony decided, was a new way to store music.

The Sony Walkman D-J50 CD walkman was not much bigger than a CD case / eBay user jafarkalantari3581

This new format was the MiniDisc. This development was spurred by two inventions: a new audio compression format called ATRAC and a storage system called the magneto-optical disc.

The Adaptive Transform Acoustic Codec (ATRAC) was developed by Sony engineers who figured out an important fact: your ears are good, but not that good. They are attuned to picking up certain sounds better than others. Specifically, if there are two sounds at similar frequencies, your ear can’t separate the two. This is especially true of high frequencies: our ears are more attuned to picking out low frequencies like the rustle of a tiger in a nearby tree. At higher frequencies, your ear is not able to pick out the details. So, what ATRAC does is to effectively lump these frequencies together, loosing the specific details that your ear can’t hear anyway. (That’s the theory, at least; audiophiles will argue otherwise, but let’s leave that aside for the moment). ATRAC breaks the sound down into 24 frequency bands, and selectively compresses the sound, with smaller bands (that preserve more of the detail) at lower and middle frequencies, but loosing a lot in the high bands. There is much more to the process than that (you can read all of the details here), but the end product is that it compresses the sound down so that the ATRAC version is one fifth of the size of the CD version.

The frequency bands used by ATRAC compression.

Magneto-optical (MO) discs were not a new technology: they had been commercially available since 1985. Like a CD, they use a laser to read data from the disc, which is stored on a reflective medium. But unlike most CDs, they can be rewritten. To do this, the laser is turned up to heat the material inside the disc, and a magnet changes its polarity. By rapidly alternating the magnetic field, the data is written out to the disc, and it can then be read by the low-power laser again. This process could be repeated many times, and it is critical to why MiniDisc became popular in certain areas, although Sony had originally seen it as a read-only medium.

A Sony MiniDisc in its protective sleeve / Flickr user Orin Zebest

The music is recorded onto the MiniDisc, which is a small disc that looks similar to a CD, but smaller. Because the surface is sensitive, the disc is enclosed in a hard case, with a cover that slips back to reveal the disc itself. This case is just over 2.6 inches wide, much smaller than a CD or a cassette tape. Each disc could hold 74 or 80 minutes of music, although this could be expanded with later models that could compress the music more to hold up to 320 minutes.

The MiniDisc slides into the player. Many portable MiniDisc players were note much bigger than the discs themselves / Flickr user Tom Paige

The first MiniDisc players were launched in 1992, accompanied by a large advertising campaign touting the benefits of the new format. Initially, Sony tried to pitch it as an alternative to CD, a new format where you would buy albums on a MiniDisc. The first pre-recorded album was Emotions by Maria Carey, which was perhaps indicative of the state of mind at Sony after the launch was a spectacular failure, with Sony reportedly selling less than 50,000 players in the first year.

Maria Carey shills for Sony MiniDisc in Japan

The MiniDisc never caught on as a pre-recorded music format, as CDs were the music format that everyone used. Never ones to admit defeat, Sony decided to try again in 1996. This time, they decided to play up the recordable and reusable aspects of MiniDisc, touting their new discs and portable players as being tougher, better and cooler than CD or tape, because you could easily move tracks from CD or tape to MiniDisc, then skip or shuffle tracks on the player.

A MiniDisc advert from the UK in 1997

In the US, Sony used grunge rockers Reef to advertise the benefits of MiniDisc. The advert included a scene where a clueless record company executive throws the MiniDisc out of the window, perhaps a snide comment on the fate of MiniDisc as a pre-recorded music format, despite Sony’s own efforts to promote it.


This relaunch met with some success: the MiniDisc players were lighter and more flexible than CD players, and they offered the skip protection and shuffle play features that cassette tape players were missing. Other manufacturers (such as Aiwa and Sharp) supported the format and started offering recorders and players. The new breed of portable MiniDisc players like the Sony MZ-R90 could record music directly from the digital output of a CD player, so the quality was great. You could also sacrifice quality for more music, storing up to 320 minutes of audio on those that supported the higher compression levels. And the NetMD players that were launched in 2001 took this a step further; they could be connected to PCs so you could copy MP3 files from you computer to MiniDisc and keep the digital quality.

The Sony MZ-N1, released in 2002, was widely regarded as being one of the best portable MiniDisc players and recorders / Minidisc.org

Unfortunately, Sony shot themselves in the foot with this. The only way to use MP3 files on a MiniDisc player was to Sony’s own software. Early versions shipped with a program called OpenMGJukebox that used a copy protection system called OpenMG. At the behest of an industry group called the Secure Digital Music Initiative (SDMI), this placed a limit on the number of times you could copy music stored on your PC: you had to “check out” the file through the software, which only allowed you to send it to a MiniDisc 3 times. Once you had copied it for your allotted 3 times, you could not even play it on your PC: you had to “check in” one of the copies of the file, where the software removed it from one of your MiniDiscs. Needless to say, this made it unpopular, and most people just copied the music straight from CD (which didn’t require the same process) or used software that hacked around the OpenMG system. Eventually, Sony removed the copy protection requirement, but the software was always awkward and clumsy compared to the drag-and-drop copying of portable MP3 music players.

A pile of MiniDiscs and a SharpMD-MT90 Minidisc recorder / UC Berkeley

One niche that loved the MiniDisc was radio journalists. The aforementioned ability to write to MiniDiscs meant that you could record to them with many portable MiniDisc devices, and the ATRAC compression worked extremely well for voices and ambient sound recordings. It didn’t have quite the quality of DAT, but it was cheaper and more reliable than the notoriously finicky DAT recorders. The UC Berkeley School of Journalism still offers instructions on how to use them to capture interviews. MiniDiscs also found a home with live music bootleggers, as they were small enough to be concealed about your person for covert recording.

But this relaunch had a limited lifespan. In 2001 Apple announced the iPod, which allowed you to copy MP3 files without limitation. When announcing the iPod, Steve Jobs said…

“There are large companies like Sony, that haven’t had a hit yet. They haven’t found the recipe for digital music. We think that not only have we found the recipe, but that people will trust the Apple brand”

Steve Jobs announces the iPod in 2001

The benefits of the iPod over the MiniDisc were obvious: the first iPods offered 5GB of capacity that meant up to 1000 songs, or hundreds of hours of music, while each MiniDisc held just 320 minutes at most. And the iPod didn’t ask where the music came from, or limit how you could copy it: it accepted most MP3 files without complaint or limitation. This caused a seismic shift in this industry: the iPod went on to sell millions, while the MiniDisc remained a niche product that was loved by some, but ignored by most.

The writing was on the wall. The MiniDisc format lost ground over the early 2000s as MP3 players got better and better. Even the uniqueness of MiniDisc being able to record audio on the player was lost, as solid state recording devices like the Tascam DR-100 started offering more flexible recording and editing features than MiniDisc ever could for professional users.

Sony stopped making portable MiniDisc players in 2011, and the announcement in February of year is the last nail in the coffin of this format. But let’s remember it for what it was: a innovative system that used technology in an interesting way, but which was hamstrung by inept marketing and arbitrary restrictions.

A Depeche Mode album on MiniDisc / DepMod.com

To find out more about MiniDisc, the first place to go is the excellent MiniDisc.org, which has an excellent history of the format, plus a list of pretty much every MiniDisc player, recorder and system that was ever released. The site also has a strong community of MiniDisc users if you are trying to get an old MiniDisc player working again. A lot of MiniDisc players are available on eBay, and Amazon still sells the blank discs and players, although few are still being manufactured.