i heard somewhere that playing a CD on a computer will somehow harm the CD. is this true? if so, how?
No, it’s not true. The reading mechanism inside a CD-ROM drive is functionally identical to that in a CD player. There is no contact between the read head and the CD in both cases. The only possible source of damage I can think of would be leaving a CD in the drive of a poorly-ventilated computer, where heat could potentially cause warping, but I’ve never heard of an actual case of this.
Well, it shouldn’t hurt the disc.
There are reports of high-speed CD-ROM drives causing discs to shatter, simply by spinning them so fast that they can’t hold together any longer. CDs were only intended to tolerate 300 RPM or so. A fast CD-ROM will exceed 10,000 RPM easily, so it’s not surprising that the vibrations and G-forces of these high speeds stress the disc a bit. I haven’t heard of an audio disc shattering, but I can’t see any reason why it wouldn’t, either.
If you’re worried, you can turn off “Digital CD Playback” in the Windows control panel for your CD drive. Many drives will cap the RPMs to some reasonable number when playing audio CDs this way (which also reduces the noise the drive makes), but not all do.
I wouldn’t fret too much about it, but I wouldn’t play any precious out-of-print treasures in a 50x CD-ROM, either.
That new show on Discovery, Mythbusters, covered this. They attached CDs to electric grinders and measured at what RPM they’d fail. I think they all failed above the fastest CDROM speed, but only just above it.
And when they failed, they failed! That is, they literally exploded and sent razor sharp shards of plastic everywhere!
They sure do – this is exactly what happened to my father’s Windows 98 CD. He had to disassemble the drive to get all the shards out.
I think it should be pointed out that the ones that exploded were the ones they’d “pre-treated” to weaken them. I remember a little under a year ago a movie clip was making the 'net rounds of a guy who put fresh CDs on hand-held versions of the same tools Mythbusters used and ran them up to full speed. Even when he knocked them off while still spinning they ran across the floor, shot up his door, and fell down out into the room again (sometimes multiple times before running out of steam) all without breaking.
Don’t put any stickers or labels on CDs. Doing so makes the CD imbalanced and causes it to vibrate ever so slightly at high speeds, dramatically increasing the risk of catastrophic destruction over time.
I have personally had a couple disks shatter in an 52x drive - after the third one, I replaced the drive with a CD-RW drive, and have had no problems since.
Audio CDs are played back ax 1X speed. Otherwise the music comes out at the wrong rate, like alvin & the chipmunks.
So there’s no difference in mechanical stress between a computer playing an audio CD and a stereo playing an audio CD.
Now DATA CDs are a different matter.
And a CD full of MP3 files is a DATA CD. Those play back at the full speed of the drive, and for a 48x or better drive you do run some risk (1 in 10,000 maybe) of the disk shattering, particularly if it’s chipped or cracked or out-of-balance as the other have said. Assuming it’s undamaged then failures ought to be in the 1 in several million trials range.
Finally, using a computer to make a copy of an audio CD will have the computer treat the CD as data and read it at max speed. If you’re copying to another drive, generally the speed on the read drive will be limited to the speed on the write drive which is much lower, say 6x, nowhere near enough to risk damaging the audio CD.
But if you only have 1 CD-RW drive to read & write the copy, then the program will read the CD at max speed while copying the data to your hard drive and then write it back to the blank CD at lower speed.
Only if you force it into the 3.5" drive
I have only anecdotal evidence for this, but I had a Gateway computer for a few years that had chronic trouble with the CD drive for some reason. Gateway replaced the drive three or four times while I had the computer.
Anyway, I stopped playing audio CDs on it when I noticed that the drive was scratching the heck out of my CDs, one of them so badly that it became unplayable. No such trouble with my actual stereo; I take good (some might say “obsessive”) care of my CDs, and that computer was the only place they were getting scratched.
Obviously, though, that was just a poorly made model.
A lot of older drives - from the mid to late 90s - probably do play audio discs at 1x all the time. I’ve used quite few like that.
But I’ve got a CD-ROM drive (on my work machine) that certainly spins pressed audio CDs (not MP3 CD-Rs) at a lot more than 1x - probably closer to 48x. It sounds like a jet engine ready for takeoff. It does this regardless of the Windows “Digital CD Playback” (DCDP) option, although the drive’s on-board DACs and front panel headphone jack only work with DCDP turned off (so the option does change the operation of the drive - just not the spindle speed). It’s a LiteOn, factory installed in a Dell - so it’s not exactly a rare model, either.
My home drive, by contrast, spins audio CDs at full ultra-whine speed when DCDP is on, but very slowly and quietly when DCDP is off. So I leave it turned off - I don’t understand the purpose or appeal of that feature anyway.
So certainly some CD-ROMs can spin audio discs slowly, if the system is set up correctly. But I wouldn’t want to make a blanket assertion that they’re all that way.
How so? The rate of data transfer may be limited, but the readers don’t generally slow down unless no data at all has been read for many seconds. A lot of people doing CD-to-CD copies today are going to be ripping and burning at a lot more than 6x anyway.
As to the larger question of MythBusters and the real-world risks: There’s an archived story at PCWorld.com that quotes representatives from Plextor and LiteOn (leading optical drive makers) admitting that shattering CDs are a real-world problem, even at 48x speeds, let alone 50x or more. They claim the failure rate is “low” - 1 or 2 failures per 10,000 discs.
Personally, I find that pretty much unacceptable. If a CD drive couldn’t read 2 in 10,000 discs, that would be one thing, but to have the disc - possibly with valuable and/or difficult-to-replace data - and very likely the drive itself - violently self-destruct in 2 of 10,000 cases strikes me as ridiculous. In what other household appliance would that be considered acceptable?