back to article 'Portable' CD player puts MP3 into a spin

During the transition period between technology formats, such from CDs to MP3s, consumers inevitably go through a period where they want 'all in one' players'. So, one designer has developed a concept MP3-cum-CD player that promises to play MP3 and traditional CDs, but in a way that’s anything but traditional. The DMP looks …


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  1. Anonymous Coward
    Anonymous Coward


    Given that CDs need a nice dark environment to work and a CD spinning at around 500rpm (centre) to 200rpm (edge) this is going to be poor.

    Lost fingers, music skipping and the fact that this solution is not mobile I would stay well clear.

  2. Adam C

    Am I the only one.....

    That thinks this is awesomely awesome? In a weird, niche kind of way? :D

  3. Daniel Bennett

    I'm, Spinning around

    No Touchy!

    Keep your hands to yourself!

    But seriously - Health and Safety anyone? Can chop your hands off with that thing !!!

  4. Alien8n


    Stick some ripping software in there and that would be perfect.

    I have to admit I really like the concept of that.

  5. Chris Purcell

    Third use?

    I wonder if it can serve a third purpose - as an angle grinder?

  6. Martin Saunders

    Plastic cover?

    I'm sure it wouldn't be too hard to come up with a style of caddy system that holds the CDs in storage and can be slotted in to the player when in use.

    Nice design, particularly if you can rip the CD music and store on the flash ram.

  7. /\/\j17

    I Guess The Question Is...

    ...will it be able to rip the CD to it's internal MP3 storage?

  8. N1AK


    What would make this useful would be if it can do highspeed ripping of CDs onto it's memory. I doubt I'd carry it around and a box of CDs to play when I get somewhere I could use it.

  9. Anonymous Coward
    Anonymous Coward


    If it'll rip the inserted CD it makes more sense.


  10. Marcus Haas

    Reminds me of the Audio Technica Soundburger

    Reminds me of a device marketed by Audio Technica (better known for tonearms and pickup cartridges for turntables) in the 1980s called the Soundburger:

    I got one from Rumbelows (remember them?), heavily discounted to £25 from about £90 (guess they didn't sell).

    Bizarre as it might seem, the audio quality was astonishingly good.

  11. thomas k.

    Back in the day, Sony ...

    Back when the little mini-CDs were first introduced, Sony had a very small mini-CD player that was 'open' on two of the adjoining sides. By opening the lid and sliding the spindle diagonally from the center of the player out to the corner where these 2 open sides met, you could mount and play a regular-sized CD, 3/4s of which spun exposed outside the case. What's old is new, I guess.

  12. Matthew Hale

    Nice design...

    ...especially as others have said, if it rips....

  13. Peter Pirie

    Could be a handy tool

    ...I don't know about how often I'd use one to play CDs, but if it could burn DVD or even Blu-Ray...

  14. Parax

    de ja vu

    Im sure I've seen this method before?

    Ah no I remember it was a half a walkman cassette player from hong kong in about 93-ish. it had half the tape sticking out the side... damn if only i could find a link to a picture...

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  16. Gav

    ripping & blinding

    Course it'll rip. Your hands, your clothes. Just about anything it comes in contact with.

    And think of the fun that'll be possible with that exposed laser.

  17. Nick Pettefar


    I had a very small CD player about 15 years ago, a small square affair which covered slightly more than a quarter of the playing CD. Unfortunately it died.

    This is a great idea and would be even better if it could record the CD's content, MP3 encoded, in its internal memory.

    What faff about slicing your fingers off, putting it in your packet, ... pah!

  18. Stu

    More room how?

    So how does opening the unit the way it does create more room for a CD to fit? It clearly rotates around the central hub point - wouldn't give you any more space - I'd wager the CD fits just fine with the unit 'closed'.

    Of course, it's just a gimmick, looks ultra-modern, and as is the case, means lack of basic practicality - it really wont work anywhere but sat on a flat surface.

    @'Rubbish' guy - In this unit, it appears the CD read head is indeed enclosed in a darkened area in the main body, for the read head to work just fine. All CD players have a little external light falling onto the opto-electronics, but this method appears to allow even less light into it because its just a thin slit for the CD surface to occupy. I'd wager the design even keeps the lens cleaner for longer.

    But other than that its a machine for the table and nothing more.

    All CDs though, are not made equal, and some are slightly warped. The CD specs state that there is quite a large degree of variation in the shape allowed before it will stop working - ie if you put in a warped disk it will undoubtedly grind against the slit edges and scratch your disks!

  19. Andy Jones

    FLAC / OGG?

    1. Will it support FLAC or OGG files?

    2. Will it be yet another MP3 player that is locked into the Windows environment.

    3. If yes to 2 will it be encumbered with DRM?

    4. What is the battery life?

    If no to 1 and yes to 2 then it is no good to me as an portable music player. I will stick to my Trekstor Vibez (terrible name, brilliant product) as it can play multiple formats and works well with Linux. I am also not bothered with poor quality rips so I use the FLAC format.

    More importantly, if I am listening to a CD and I encounter trouble of the streets, is it possible to use the contraption to flick the CD at my enemy frisbee style to disable them?

  20. Luke

    Re: Rubbish

    "..CD spinning at around 500rpm (centre) to 200rpm (edge).."

    Interesting ideas about the laws of physics there Jimmy-boy... so the centre of the disc (which is fairly solid and not actually much like a fluid at all) spins round 2.5 times for every revolution the edge of the CD performs? Wrong is soo many ways..

    perhaps you are thinking of angular velocity, in which case the edge moves *faster* than the centre as it has does the *same* number of revolutions, but has further to travel, hence it has a *higher* angular velocity

    Unless, of cource, the concept DMP has some sort of space/time warping effect, in which case better call Kylie - I mean the Doctor

  21. Ted Treen


    Methinks a CD revolving at 500rpm centre and 200rpm edge won't stay in one piece long enough to chop fingers, skip music etc. The SPEED in cm/sec will vary between edge & centre, but not the rpm.

  22. Anonymous Coward
    Anonymous Coward

    To prove there's nothing new in this world

    Check out the Sony Discman D-88, an early 90's CD player which did much the same thing - albeit without the MP3 capability.

  23. Steve

    spinning tops dangerous?

    A lightweight disk spinning at 1x rate (500rpm max) can’t be considered as being anywhere near as dangerous as a spinning top.

    OK it's not really practical - but it is a visual gizmo so I would still have one. Pity it won't look so good when playing the 'home made' backup disks....ahem!

  24. Parax


    "500rpm (centre) to 200rpm (edge)"

    Haha fell off my chair what an idiot..

    BTW folks this is not a 48X data disc its a 1x Audio Player!

  25. Nick Ryan Silver badge

    Dark environment ...

    Erm, the entire CD doesn't have to be in a dark environment, just the bit that contains the reading head. And even in this case, there is some leeway available as it doesn't have to be 100% dark, just with enough "contrast" in the light levels of laser/not-laser to accurately read the CD track.

    As for removing fingers, these discs don't go round that fast, don't have sharp edges and have very little mass behind them so are largely harmless. still wouldn't recommend gently running soft skin (like fingers) on the edges when they're running, but they certainly wouldn't remove a finger. Biggest problem is likely to be the practical problems of keeping the disc spinning at a constant speed in an environment where there are things to get in it's way, dust, hair, dirt, etc to fall onto the disc and all manner of other problems. Besides which, how do you actually hold such a device and without jamming digits / clothes, etc into the mechanism or just dropping the headphone cable into it's mechanism?

    Nice concept, will never go anywhere.

  26. Anonymous Coward
    Anonymous Coward

    Original Design?

    Who sez the design is original? Check the Sound Burger portable LP player for the Walkman generation at .

    Are they perhaps related?

  27. Anonymous Coward
    Anonymous Coward


    "a CD spinning at around 500rpm (centre) to 200rpm (edge)"

    Does anyone else here find this statement hilarious?

    The 'rpm' speed of a CD is the same in the centre as on the edge, genius.

  28. Anonymous Coward
    Anonymous Coward

    Re: Am I the only one.....

    No, I think it is awesome as well... practical, no, awesome, absoltuely.

  29. Cameron Colley

    LCD Display?

    Funny, I only see one LCD, not some kind shop-window style display unit containing a few.

    Nice Compact CD Disk player though -- I'd have one just for novelty value.

  30. Ross Fleming

    Awesome product! But would never buy it..

    I love that product! granted I would never find a use for it, but it's certainly got a certain, as the French say "I don't know what".

    To counter the criticisms, it wouldn't be all that harmful - we've all tried fooling a discman into playing while the lid was open. Unless you're sharpening the edges of your cd's, there isn't enough angular momentum to hurt you. I've managed to stop a CD spinning in said open discman. Also, it only needs a dark environment where the laser is - from what I can see, one of the legs(?) would house the laser and would be dark enough.

    Still, would never buy one...

  31. Robert Hill

    Just brilliant design...

    I don't care if it isn't portable, I don't care if it doesn't work on the move..

    It is a great example of thinking "outside the box", literally.

  32. Karim Bourouba

    didnt batman use one of these?

    in batman returns?

  33. Dave


    If you can get a version that'll play LPs, I'd be up for that. Bit of a bugger to carry around in a hip pocket, though.

  34. Law


    they should have:

    - ripping to internal storage,

    - ability to act as an external USB CD/DVD drive for PC's

    - ability to write to DVD/CD from a PC and it's internal mp3's storage

    - ability to read mp3 cds/dvds

    - wifi abilities - so we can all share the music we rip! :)

    But most importantly, once all these features are added (and DRM free btw), it already has the ability to turn upright, point at recordindustry/apple/microsoft - and give them the V's! :)

  35. Tom Peach

    RE: Rubbish

    Can you expand on how a CD travels at a different RPM at different points on the disk?

  36. Timmy

    Portable CD Ripper

    Would be freakin' sweet if it could rip CDs, or even make images of them on the go.

  37. Dom

    Use your noggins

    The rpm varies depending which bit of the disc is being played, hence "500rpm (centre) to 200rpm (edge)".

  38. Anonymous Coward
    Anonymous Coward

    Holy Crap!!

    ...CD spinning at around 500rpm (centre) to 200rpm (edge) ...

    The torque in that thing when it finishes playing must be something incredible - mind your fingers when you change discs everyone!

  39. Anonymous Coward
    Anonymous Coward

    Nyyeeeeearrrghhh! <crosses legs>

    @ Nick Pettefar:

    " What faff about slicing your fingers off, putting it in your packet "

    Man, if that thing's got a razor sharp edge rotating at 200rpm, the *last* place I'm going to be putting it is anywhere even *near* my packet...

  40. Anonymous Coward
    Anonymous Coward


    Unless the manufacturer has decided to use a chainsaw engine to rotate the CD, I seriously doubt that it would be possible to injure yourself, shred clothing, etc. with this. That said, obviously you're not going to be able to use this as a portable when playing a CD, and what of the 'Warning invisible laser light' stickers that all laser equipment has--seems like it'd be pretty easy to look into the laser compared to a 'normal' device.

  41. Anonymous Coward
    Anonymous Coward

    Luke's rubbish.

    " "..CD spinning at around 500rpm (centre) to 200rpm (edge).."

    Interesting ideas about the laws of physics there Jimmy-boy... so the centre of the disc (which is fairly solid and not actually much like a fluid at all) spins round 2.5 times for every revolution the edge of the CD performs? Wrong is soo many ways..

    perhaps you are thinking of angular velocity "


    He was thinking of the well-known technique that CD players use to maintain constant linear velocity under the head: they spin the disc faster when reading the regions near the centre than when reading the regions near the edge.

  42. Richard Dudley

    Re: Re: Rubbish

    Hey Luke,

    Its you that's got CD physics wrong, not our Jimmy. CDs are read out at a constant linear velocity (CLV) which means they rotate less quickly when the head's at the edge than when its in the middle (starting point). Jimmy's referring to the head's position, not a point on the disk.

  43. chris

    Not @Rubbish

    The first post relates to the speed of the disk when reading from the centre or the edge of the disk, not the speed of the disc at that location.

    When reading from the edge the disk, it spins slower, than when reading from the centre.

  44. Mike Holden

    Rotation speed

    I think what the original poster said about different rotation speeds is correct. He's not saying that different parts of the disk spin at different speeds at the same time (which would obviously break it), but that the whole disk spins at different speeds depending on which part of the disk is being read at the time.

  45. Anonymous Coward
    Anonymous Coward

    Lawsuits, weapons and the rotation thing

    In this age of litigation over stupid stuff, the manual probably weighs 2 pounds, 1.9 of which are pages of disclaimers and safety warnings so that they can't be sued by some pillock who got a booboo on their pinky finger from a spinning CD. Dateline NBC will probably run a sensational horror piece about people having limbs severed by this anyway, and will modify it to spin the disc at 10,000rpm just to make sure they get the result they want...

    How about an improvised weapon? Sharpen the edge of a CD, maybe put some serrations on there. Or fashion something similar but deadlier out of a mini CD with a sharpened metal normal-CD-sized rim attached? Hours of fun for all the family!

    On the rotation speed thing: the *entire* CD spins at 500rpm while playing at the start of the CD (in the center) and 200rpm when playing right at the end of a full 74/78 minutes (the outer edge of the disc), or somewhere in between the two depending on how far toward the end of the disc playback has reached. That way the surface speed passing by the laser is always constant. Though a CD spinning at two speeds at the same time would be quite a thing to behold, preferably from behind a sheet of plexiglass or similar. :)

  46. Trevor Watt

    @ the RPM Pedants

    When reading data from the disk the machine needs to change the CDs RPM. When the data is read from the inside it spins at 500 RPM, decreasing slowly as it reads through all the data across the disc until it slows to 200 RPM for the data round the outside edge.

  47. Anonymous Coward
    Anonymous Coward

    500 rpm / 200 rpm

    Oh, geez...

    FFS... 500 rpm when it is READING FROM THE CENTER, and 200 rpm when it is READING FROM THE EDGE, because AUDIO CDs must keep the same LINEAR speed when reading...

    Yes, CD-ROMs are CAVs (continous angular velocity) so when they are read from the edge, they are read FASTER. The RPMs are kept constant in this case.

    In short, there is a difference between how Audio CDs and CD-ROMs are read, or at least back then when the technology came out. Everything now should be CAV...

    Tong in cheek?

  48. Jezar

    Oh Dear...

    Why do people have to write such ignorant, smart@rse comments?

    The original poster was CORRECT inasmuch as the RPM of a CD *does* change from the centre to the edge. However, they meant throughout the DURATION of the playback - from centre (programme start) to edge (programme end), and NOT at any one moment in time! - D'oh!

    CDs are recorded in what's known as a CLV format (constant linear velocity) as opposed to CAV (constant angular velocity) - so the rotational speed gradually slows down towards the end of the recording.

    It's usually a good idea to check your understanding of the facts before taking the p*ss out of other people.

  49. Kevin Hall

    Will anyone buy it?

    Sure it's a clever design but will anyone buy it? It clearly isn't a player you can use on the move as the rotating disk will snag on pockets or bags so I'm not sure where it'll be useful. I do think there is life in the MP3/Ogg format on a portable CD player but not in this form factor. You'll struggle to find any portable CD player these days as cheap MP3 players, especially flash based ones, have killed the market.

  50. Crispin

    Luke and Ted Treen

    I think what Rubbish meant was that the CD spins at 500rpm when the head is reading data from the middle of the disc, and 200rpm when it's reading data from the outside of the disc. I hope so anyway, otherwise physics has indeed been warped.

  51. Craig Collier


    For an early devlopment design, its brilliant.

    Few thigns it needs to be come usable tho, some sort of sheath, i.e., you insert the cd while closed, and then instead of just openning up a little bit, the two sides would fold all the way round the CD enclosing it in some sort of concertina-style casing - or somethign like that.

    I definitely want one - and if it ripped CDs to mp3s, then it wouldn't even need redesigning.

  52. Simon Still

    Safety and disc speed

    As a load of people have said, there were no problems with the old Sony player. No reason the surface needs to be especially flat either.

    IIRC the speed a CD spins at changes as the laser moves across during playback - 200rpm while it's reading the edge, 500rpm while reading the centre (to get sufficient data past the read laser).

  53. Anonymous Coward
    Anonymous Coward

    Safety and disc speed

    As a load of people have said, there were no problems with the old Sony player. No reason the surface needs to be especially flat either.

    IIRC the speed a CD spins at changes as the laser moves across during playback - 200rpm while it's reading the edge, 500rpm while reading the centre (to get sufficient data past the read laser).

  54. Simon Ball


    The only reason for multi-format players is to allow consumers to protect their investment in an obsolescent format. However, given that anything that is on CD can be easily and quickly ripped to MP3, I fail to see the point of this device, unless, as others have said, it allows you to rip on the go.

    For regular use as a CD player it's inherently flawed - IT may be ultra-portable but a decent selection of CDs isn't.

  55. Matthew Cochrane

    Not all that original...

    It looks a bit like a Sound Burger portable record player. You can see one on this site:

    As someone else pointed out you couldn't put this in your pocket whilst it was playing a CD, you couldn't really listen to it in a car or on a train, and it would scratch the discs really easily. Also it looks like if you closed it whilst it was playing it would fire the disc at some speed.

  56. Brent Alldred

    Great, just needs a hanger

    All it needs is a hanger.

    Assuming the CD player is just to be used inside or in a car, then hanging it from somthing should bypass the accidentally hitting the spinning CD issue.

  57. Anonymous Coward
    Anonymous Coward

    There's nothing new under the sun

    Brings a whole new meaning to the phrase 'ripping a CD'. Not a new idea, however - it reminds me of a product called the Audio Technica Sound Burger. It was basically a vinyl record player that looked vaguely like an over-sized set of heated hair straighteners. You flipped it open in the middle, popped your LP in and it played it - most of the LP was left flopping around in the air like the above monstrosity. Did a pretty damn good job of destroying vinyl, as I recall...

  58. Doug Smith


    I thought I'd be the first to say it's "Kewl" ......not

    Maybe the designer could add rotors to the top and it could hover above the users head tethered by his headphones so it won't go flying off.

    On second thoughts maybe it would gain extra long distances as a frisbee...straight into the furthest bin!

  59. Darrell


    It should have a quick release button so you can shoot the cds out of the player, kinda like a cross between those helicopter rotor toys we had as kids and a ninja star :)

  60. Anonymous Coward
    Anonymous Coward

    How cool!

    A musical angle-grinder. Who would have thunk?

  61. Anonymous Coward
    Anonymous Coward

    Re: Rubbish

    How can the center of the disc spin at differnt rpm to the rest of the disc?

  62. Anonymous Coward
    Anonymous Coward

    Seen before

    I used to have a Sony D-88 Discman that would have the same effect, just sans the folding action. It's pretty nice if you just want a very transportable device, not a portable one.

  63. Michael Sheils

    ripping would be fantastic

    but I mainly want one for the awesome geek-weapon potential.

    "My supernature CD is going to cut you up!"

  64. Craig Leeds


    Sony did a CD player like this back in the 80's

  65. Steve

    No more talk

    There's no torque behind a spinning cd, it won't take a finger off, and most likely won't even give you a small cut, it will just stop if you touch it.

    Isn't this guy a bit late to market with a transition device though, maybe 5 years ago....

  66. Anonymous Coward
    Anonymous Coward


    It plays MP3s, plays CDs and now works as a self defense weapon!

    I wanna take one to the airport with a cd playing just to see what happens.

  67. Steven Jones


    So just how long does it take to rip the CD in the first place making this idea completely redundant ? I suppose if you can't wait to get that brand new CD home then maybe it has that use. Given that virtually everybody with an MP3 player has access to a computer, then just where is the market for this thing?

    As a desgn idea it looks great, as something I would buy I can't imagine why I would do it. I'd prefer all that extra space and weight taken up by the likes of motors and read heads to be allocated to more space for memory and batteries.

    For those talking about the impossibility of spinning CDs at a different RPM rates at different distances, then of course you can't do that at the same time, but it is perfectly possible to vary the RPM rate as the head tracks across the disk. Indeed this was a technique called CLV (constant linear velocity) as opposed to CAV (constant angular velocity). Audio drives were (I hink) mostly CLV, but no doubt the same behavior is now mimiced using CAV and buffering as CAV is simpler mechanically.

  68. Anonymous Coward
    Anonymous Coward

    Call me old fashioned

    Small ain't necessarily best.

    Our kids lost so many MP3 players because they were so b****y small we have gone back to CD/MP3/WMA players. Result - kids embarrassed but no players lost. Excellent.

    Love the third use as an angle grinder. Wonder if a diamond cutting disk would fit?

  69. Carl

    500 rpm centre, 200 rpm edge

    The reason for the difference is that the track goes past the head at constant linear velocity (unlike a record player). So the motor spins the disc at 500 rpm when the head is in the centre, dropping to 200 rpm as it moves towards the outside. That's why when you stick a duff disc in you can hear the motor spinning up and down as the head seeks from the inside to the outside.

  70. Kevin Eastman

    Old technology made new again

    Not much new about this except the design and format of playing the mp3's, I have a portable cd player, that I have had for a couple of years now, which not only plays regular cd's, but mp3's burnt onto a cd as well. Has come in very handy on occasion.

  71. Rhys Hopkins

    @Luke and Ted Treen

    Did you consider that perhaps the CD spins at 500rpm when reading the centre of the disc, and at 200rpm when reading the edge of the disc, in order to maintain a consistent speed past the laser?

  72. Tom

    Variable rotation speed

    Stop trying to be smartarses and think about what the guy said. How could you approach this concept in such a way that it makes sense, rather than leaping to the conclusion that the poster was an idiot and then looking like one yourself?

    When the player is reading data from the centre of the disk it has to spin the disk faster to maintain the same bit rate.

  73. b bain

    RE: @Rubbish

    CDs rotate at different speeds depending on what part of the disk is being read, they rotate at about 500rpm when reading near the hub of the disk, and at about 180-200rpm when reading near the outer edge.

  74. Kevin Johnston

    spin speed

    I suspect that @Rubbish refers to the different speeds the disc spins at when reading the track near the centre of the disc and towards the edge of the disc.

  75. Pedantic Twat

    to @Rubbish and Luke.........

    To be fair, @Rubbish is correct, if the thing *could* make a CD rotate at 200rpm in the middle and 500rpm at the edge, then indeed it would not 'stay in one piece for long'.

    But then Luke is also correct....

    Ho hum, back to work .......;-)

  76. Antoine

    Sure... Cut fingers

    OMG, a CD running at 1x. When you touch a spinning CD it just slows down and starts to skip. The motor in there is probably consuming less than 2W. It's REALLY easy to stop a spinning CD, it's not a sharp blade with a 300W+ motor making it run at a few thousand RPMs.

    Sony had a 33RPM player like that.

  77. Dale Reese

    Speed varies while playing

    The main parameters of the CD (taken from the September 1983 issue of the compact disc specification) are as follows:

    Scanning velocity: 1.2–1.4 m/s (constant linear velocity) – equivalent to approximately 500 rpm at the inside of the disc, and approximately 200 rpm at the outside edge. (A disc played from beginning to end slows down during playback.)

  78. Name


    Gees CDs spin faster *reading* inner tracks than they do reading outer tracks. The drives change the disc rpm to maintain a constant linear velocity at the read head.

    As for lost fingers, well if you try hard enough a CD can get about 1/4 way through a bit of 2 by 4.

  79. Kenny Swan


    And the advantage of this over portable CD players that will play MP3 from a data CD are what exactly?

  80. Matt

    @Rubbish and @Ted

    You are both wrong I'm afraid, chaps. Audio CDs are read at constant linear velocity, which means that when the data is being read from the middle of the disc it must spin faster. So, going from the beginning to the end of the content, which works from the middle to the edge, the rate will indeed decrease from ~500 to ~200rpm.

  81. Marcelo Rodrigues

    CD rotation speed


    CDs have rotational speeds from ~150 to ~300 RPM (~300 RPM at the centre, and ~150 RPM on the border). They use CAV (Constant Angular Velocity), hence the variation on the speed. These speeds are the original spec of CD (CD 1x). The last reader with CLV all the way up from beginning to end where the 12x units. Above it they use either CLV (Constant Angular Velocity) all the time (a 52x can, rougly, read at 28x in the beggining, growing slowly until reach 52x at the very border) or a mix of both.

    @Ted Treen & Luke

    He wasn't clear enough. I believe that he was saying that the disc is read at 300 RPM at the centre and 150 RPM at the border. Wich is roughly true, for a 1x reader.

  82. Anonymous Coward
    Anonymous Coward

    "Rubbish" is right.

    He means that traditional cd drives vary the speed of the motor in order to maintain a constant data read. So when the outside of the disk is being read the motor gives the disk a lower rpm than when reading the center.

    Sorry chaps you may have your physics right but make sure you understand how things work before telling people they're wrong.

  83. Marcelo Rodrigues


    I got the RPM wrong. Original guy was right: about 500 RPM at the centre and 200 RPM at the border. But the rest of my post was OK. :)

    Don't know from where I got the 150-300 figure. Ah, well...

  84. J. Cook Silver badge

    CD revolution rates...

    Luke wrote:

    "Interesting ideas about the laws of physics there Jimmy-boy... so the centre of the disc (which is fairly solid and not actually much like a fluid at all) spins round 2.5 times for every revolution the edge of the CD performs? Wrong is soo many ways.."

    The disc rotates at a variable speed due to the data stored on it being at a constant density. Naturally, the disc has to be rotated faster as the optics are near the hub, because there is less data near the hub then at the outer edge. On the outer edge of the disc, the disc does not have to rotate as fast in order to get the same amount of data. Hence, the disc rotates slower.

  85. Morely Dotes

    To echo what others have said...

    As a ripper, it's a great idea. As a CD player, it's rubbish.

    And be fair to poor old First Posting Anonymous Coward up there - I believe he's trying to say that the thinks the RPMs vary according to the position of the read head (although he's got the concept totally backward, and so far as I know it's not correct anyway), not that the inner portion of the CD spins at a different RPM from the outer portion. So he's confused, but not totally thick.

  86. Shaun

    RE: Audio Technica Soundburger

    I saw someone with a similar device at a record fair last year, I suppose it's best to have a listen before you buy

  87. HonourableTyr


    "Given that CDs need a nice dark environment to work and a CD spinning at around 500rpm (centre) to 200rpm (edge) this is going to be poor.

    Lost fingers, music skipping and the fact that this solution is not mobile I would stay well clear."

    LMFAOROFL (Sorry about that bit)

    I'm sorry this is too funny/stupid to ignore!!!

    If a circular object is spinning at 500rpm on the inside and 200rmp on the outside the outside is moving slower so the object has to be fluid (would look like a cyclone).

    It is a solid object, the inside revolves as many times as the outside.

    Secondly, you don't need dark as the red laser works fine in daylight. I have disassembled a CD drive to 'miniaturise' it in this way. Guess what? It worked fine, I could interrupt it with my fingers and it would just stop. The motor is not powerful enough to cause any kind of cut, friction burn or injury. You'd have to be very stupid/unlucky to cause yourself any kind of injury with it.

    With a good buffer, you don' need to worry about skipping, only scratches. I tested this too with my disassembled player. Took 40 seconds of complete stoppage to skip with the buffer enabled. I could start and stop it without adding up to 40 seconds and it would be fine.

  88. Ryan


    cd's slow down when the lens is reading from the edge (or is it centre? - i think it's the centre because dvd±rw drives get their peak burn speed near the edge of the disk).

    i don't think "rubbish" meant that the two speeds would be simultaneous!

    also, i don't think this would cut anything - more likely jolt to a stop and damage it's motor or even lens mechanism!

  89. Niall Mac Caughey

    Brilliant, but not entirely unprecedented

    I like it, a little lateral thinking is always worth a whirl. But something similar was done before. Hiding in a dark cupboard somewhere I have a tiny record player made by Mullard (I most of you old enough to remember the name thought they

    only made transistors).

    It's about the size of two of the original Nokia 9000s side-by-side and only a fraction of the size of an LP; remember them, 12" in diameter & made of vinyl?

    The pickup was off to one side and the player could be opened out to reveal a small spindle and a little rubber wheel which ran on the underside of the record to rotate it. The audio came from a 3" speaker driven by a small transistor amp with the whole thing powered by a couple of D cells.

    Very portable, but back then playing LPs in your pocket didn't really arise.


  90. Nev

    Been done before

    I seem to remember 3" CD players being available about 15 years ago with a similar ability to play the larger normal size CDs. Yawn.

  91. John Sykes

    Has there been a timeslip ...

    ... to 1 April?!!

  92. Chris

    Re: Different speeds on diferent disk areas

    Because of the increase in linear (not angular that is constant) velocity the further you get from the axis of rotation, a single-speed audio cd player reduces the rate of rotation as the read head moves from the center to the edge of the disk. This is to maintain a constant relative linear speed between the disk and the read head.

    IIRC, multi-speed readers (such as that nifty 50x cd-rom drive in your computer) are designed to be able to read the data faster (they have a faster internal bus) so this slowing is not as necessary. (I could be completely mistaken on that second point, though)

  93. the Jim bloke

    external CD spinning ?

    What I want is the ability to launch the CDs

    Now thats what I call CD ripping

    nostalgic ex-Tribes player

  94. Anonymous Coward
    Anonymous Coward

    How about an extra casing with a fan function

    ...for those hot days

    So while you listen to your MP3's you can get the breeze of the music... ehmmm errr... spin.

    Am I dreaming ? =P

  95. Rolf Harris

    I would SO buy one of these's not that it has to be overly practical to play CDs on the move, but it'd be great to have the option for if you're on a train or at someone's place. Especially if it could rip the CD to the MP3 player for you. It'd have to come with a lot of memory of course and perhaps play MP3s from DVD-R if you inserted one in to the unit. Then it'd be a well cool gadget.

  96. |333173|3|_||3

    Portalbe ripper

    It would be useful as a portable ripper, if you were visitng a friend.

  97. Jim

    More RPM crap/pedantry

    Late to this but couldn't help read a list of almost 100 comments ;-)

    I'm quite amazed that no-one has picked up on a couple of posters here, namely Luke and Marcelo Rodrigue. RPM is a measure of Angular Velocity, so if the rpm changes then so has the angular velocity - 1 rpm = PI rad/min after all.

    As the first poster, there is nothing there to indicate that they are referring to that fact that audio CDs are read at CLV rather than CAV. It has either been assumed that the reader knew this (and could therefore decode the writing) or that the author had read the figures somewhere and not questioned that a rigid body could act like a fluid.

  98. Alex Taylor

    Case design

    Someone mentioned that the case splitting in two doesn't actually make more room for the CD to fit.

    But surely it does create a much more stable device that can be placed flat on a table. Otherwise it would tip sideways and damage the disc edges.

    I don't really think it's designed to play CDs while in a pocket. Even then, since when does a CD have a razor-sharp edge? Nobody could possibly be injured by this.

  99. Giles Jones Gold badge

    Been done before

    I've seen similar designs before.

    Anyway, who in the hell uses discs anymore?

  100. Steve Roper

    But the REAL question is...

    Will it BLEND?

    Coat donned...

  101. Anonymous Coward
    Anonymous Coward

    Nobody remembers Back to the future 2?

    This is just the player what a girl used in the film. The player was mounted on her wrist with the cd spinning almost freely. This is just the thing to have that good old retro future feeling. (if the ever going to sell it with a wrist mount band)

    ps: If they ever have an 'upload mp3 cd' feature, this could be used to change the contents of the memory on the go by loading up a cd full of mp3-s. The same could be used for dvd-s and smallscreen mp4 players to transfer new content without using a computer.

  102. Parax

    errr.... part 2

    damn it, I'm a fool, yes ok, Constant linear velocity does mean it spins at 500 rpm over the shorter centre track and 200 rpm over the longer outer tracks (in order to cover the same distance per second) picking my self up off the floor in shame :( It did seem like it was a bit too torsionally twisted.. and yes 500 rpm is only 8rps... but still hardly any momentum whith such a light disc. Not likly to be dangerous bit youd have to rip on a table and go later. and who would want to wait an hour to rip at 1x speed... unless it did rip at 50x at 10,000 rpm then it would be dangerous, (and would no-doubt be mains powered!)

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