Why CD players will never be dead

hi steve;

the bet would be your transport + a dac of your choosing vs my cd palyer.

taking note of your statement regarding comparing transports, assuming your transport is superior to the laser mechanism in my cd player, the dac section and any mods to my player, i conjecture would be preferable to your (supposedly better ) transport and dac.

thus i have no interest in comparing transports. rather i am interested in one digital source vs another.

if you recall my visits to your rooms at the st tropez, you may recall that our tastes in sound diverge.

so i will spare you a bet that you cannot win.

the whole purpose of my statements is to indicate that our hobby is subjective.

i have only found one digital front end that i prefer to my cd player, namely the original zanden and its companion transport.

i will assume that you fabricate a fine product but i doubt it sounds like the original zanden or the original lector.

" "Error correction," which as I understand it occurs many times during the reading of a typical cd, is by definition bit perfect, i.e., the error is corrected!”

Hi Al, please take this as a question and not an argument: If information (bits) is missing from a read, how does a CDP know what that information is. It was my understanding that error correction/interpolation/concealment is a process where the CDP makes a sort of guess based on the before and after the error bits. Okay Steve, blast away :-)

11-28-11: Phaelon
If information (bits) is missing from a read, how does a CDP know what that information is. It was my understanding that error correction/interpolation/concealment is a process where the CDP makes a sort of guess based on the before and after the error bits.

Hi Tom,

Good question. The answer is that what are called "error correcting code" bits are encoded onto the CD, in addition to the audio data (and other) bits. As explained in the first Wikipedia writeup I linked to, those bits implement mathematical algorithms which allow errors in the associated data bits to be detected, and if the errors are not extremely severe (as may result, for instance, from a particularly severe scratch on the CD), also allow the exact original data to be determined.

That process is performed by the transport mechanism's electronics.

In the far more rare event that the errors are too severe to be precisely corrected, then interpolation (aka concealment) is performed, which as you realize amounts to an estimate or guess as to what the data should be. Or in extreme cases the CDP may mute, or if a non-realtime read mechanism such as a computer or the Perfect Wave transport is being used, multiple attempts may be made to read the incorrect data.

Note this sentence in the Wikipedia writeup:

The result is a CIRC [Cross-Interleaved Reed-Solomon Code] that can completely correct error bursts up to 4000 bits, or about 2.5 mm on the disc surface. This code is so strong that most CD playback errors are almost certainly caused by tracking errors that cause the laser to jump track, not by uncorrectable error bursts.

Best regards,
-- Al

Thanks Al. Terrific explanation.

So according to that wiki and what I previously thought, it is A COMPLETE FALLACY that the audio cd player reads a different set of data each time and products like the ps audio perfect wave are relying on pure marketing to make people think cd reads are inaccurate.