Originally Posted by
Shian7
LOL!... Marco, think of it like this:
There is no music on a CD, only DATA, stored as one's and zero's. It only becomes music once processed by a DAC.
The trick here is to transfer that raw data as accurately as possible onto a hard drive, this is where multiple passes (the number of times the disk is read) and error detection and correction comes in. With DAE you can take as long as you need/want doing this process to get the data from the CD with as few (if any) errors as possible. An error is reading a '1' as a '0' and vice versa.
Listening to it 'live' or converting it in 'real time' (ie. as it's playing) is a different matter, the transport has only one chance to get it right, any error detection and correction has to be done 'on the fly'. A much more tricky prospect.
A very simplistic (and possibly rubbish) explanation.
In fact that's an excellent explanation.
Half the problems with computer based audio is that many programs (iTunes included) import on a straight rip; i.e. importing the data once and running it through an error correction system - the same as a straight replay from a CD player. With certain import programs, programs that are specifically designed for complete error free importing (like Max), multiple passes of the CD are taken. The software then averages the data omitting any data that isn't original (error corrected data for example) and replacing it with the true data from another pass.
To put it another way, if you have ten identical cars all with some damage on them, by using only the good parts from each car one should easily be able to make a perfect car with no faults. This is what multiple pass software does. Of course, most CDs owned by audiophiles are unlikely to have damage extensive enough on them to require more than three passes, but in the case of buying secondhand CDs up to ten may be necessary to get as clearer data as possible.
This is where imported music has a distinct advantage over a CD player, a CD player is doing everything on the fly, reading the disc, coping with external forces, correcting errors with what it 'thinks' should be in place, sending the data to the DAC, decoding in the DAC and converting the signal to analogue. In essence it's like asking a musician to play a tune whilst it's still being written by the composer rather than the composer providing a printed sheet of music.
This is why the quality of the transport used for import is not as critical as one used for immediate replay. The CD player has one chance to get it right and must do it time and time again with as few errors as possible, an import on the other hand may take several minutes as might the decoding process, but it has multiple times to look at the data and get it perfect (or as perfect as) before finalising it in the form of a stream of correct 1s & 0s. Once this has occured the reading of it is faultless EVERY time and there's no mechanical interface to interfere with its replay.
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