> > I thought this (rather unnecessary) problem was less with > modern drives? > Another option is to use an audio CD player with digital out. > > Oyvind. The thing is that it isn't a trivial problem. To burn a CD we're pointing a laser at a spinning disk and making pits to represent the numbers we want. The actual physical mechanisms for doing this are not error-proof, although they are significantly reliable to give good results. So, we might write a wrong number by missing a single bit - what dumber do we get when '00000000-00000000' becomes '10000000-00000000' because a single bit was written incorrectly? Readback is the same issue. We read numbers, but there's no guarantee that we read the right number. There could be a single bit that got recorded just a bit weakly, or a part of the CD that was a bit more difficult to burn. (Not to even mention what happens when there's a spec of dust in the system somewhere.) >From my reading, which hasn't been that deep, all of these sorts of problems add up to a few bad bits here and there. When we 'play' a CD using a modern drive, it is my understanding that we read the disk one time and play what ever we read. If there is a bad bit in there, then you hear it (possibly) but if you play the disk a second time you might not get the same bad bit, so you really cannot track it down too easily. I think what EAC, and I guess cdparinoia also, can do is read the same section multiple times and figure out what is the 'right' answer, which is cool, but it's not a real-time operation. (to the best of my knowledge...) It's interesting to look at this problem on commercially made CDs you buy at the store. Even the best of them have to have a number of bad bits. It's just the nature of manufacturing. I spent some time a while back looking at a Steely Dan CD. Sounded perfect (to my ears) but had a number of bad bits. None of these problems are actually solved by using a digital out on the drive since the problem is created when the laser and drive electronics actually read the disk. After that point, if the problem is there, it's there on all outputs, digital, optical and analog. - Mark
