> From: superflo@... >> And this is the one of the MOST important factors, because EVERY CD you >> burn will have errors, thats why the Reed Solomon correction process is >> inside every CD player ! Also Dat has errors ! Thats why they still prefer >> well done analog tape to begin with. > > And what causes the errors you mentioned on every (Audio?)-CD that > anybody burns at home? > > Flo It's 1:30 am, and time to go home, but I'll take a brief stab at this nonetheless. ALL digital storage media designs utilize error detection and correction. CDR, ADAT, DAT, Exabyte, Hard drives, floppy discs, you name it, they all use it. It is used primarily because it allows you to greatly increase the density of the data that you can store. Essentially, you're writing the data redundantly. Vast sums of R&D money have been spent trying to determine what the most advantageous error correction algorithms are. Error correction kicks in quite often, but you don't hear anything, because it's possible to reconstruct the sample from the redundant information. Playback of a pristine CDDA will result in thousands of errors, but all or almost all will be completely recovered, resulting in perfect or imperceptibly-close-to-perfect playback. If there's a particular sample where an "uncorrectable" error occurs, most systems perform "interpolation," which means: If I know the values for sample A and sample C, but I don't know the value for B, I can make an educated guess that B is right in between A and C. Individual interpolations are almost always inaudible. If a string of several samples in a row come up as "uncorrectable errors," a phenomenon knows as a "burst error," that's often audible. In order to minimize the potential for burst errors, information is scattered into various locations on digital storage media, rather than written in a continuous stream. Playback of a CDDA with lots of light scratches will result in tens or even hundreds of individual interpolated samples over the course of the entire disc, but once again, that's unlikely to be audible. Playback of a CDDA with heavy scratches can result in skipping, muting, burst errors ("fzt") or dropouts, all of which even I can hear :-) For further info, consult Ken Pohlmann's "Principles of Digital Audio" or maybe try an Altavista search for the phrase "what is parity". (parity is the most basic error detection algorithm, and is a good place to start). As for why analog tape is still groovy, it's simply because a properly aligned and calibrated analog machine can sound absolutely fabulous. Marvin Humphrey .................................... marvin@... "...if you're doing an experiment, you should report everything that you think might make it invalid - not only what you think is right about it: other causes that could possibly explain your results; and things you thought of that you've eliminated by some other experiment, and how they worked - to make sure the other fellow can tell they have been eliminated." - Richard Feynman