Do CD-R's sound the same as originals

I would add to the response of 1439bhr the following: There might not be any errors on the copy. In fact as 14 says there should not be any. However, the reflective properties of CDR and CDRW are different than these of regular CDs. This is the main reason some audio players do not read them at all. Others misinterpret quite a few bits because of difficulties reading them. They have error correction algorythms that are meant originally to correct erors due to scratches, vibrations and dust. That is how audio data ends up interpolated and hence the sound might be inferior. Of course jitter remains a factor too... Kocho

I think CDRs sound fine for listening to MP3 sources or in the car. On my home system they are clearly marginal. Why? I think the primary reason is jitter. The CD burners clearly don't have the jitter specification that the original stamping process had. Stereophile ran tests about 5 years ago during a controversy that centered around whether different CD plants produced better/worse CDs from the same master source. BMC was the target of those complaints. The bottom line was that the various copies were absolutely identical bit for bit but they sounded different. That was the time when the significance of jitter was just becoming apparent. So it the pits are shifted ever so slightly because of a not absolutely accurate spin speed a phase shift or random jitter can be introduced.

Good point about reflectivity. Too bad that $200 CD burners can outperform big buck audio players :-( Concering error correction algorithms: notice I used the term "correctable error": this is an error which is detected by the error correction algorithm and CORRECTABLE -- the original data word is restored to its proper value. I won't go into technicalities, but the use of redundant bits allows this. For example in an (11,8) code, 11 bits are recorded to represent 8 bits of data input; at playback time an 11 bit is read and the error correction algorithms decides which 8 bit word was intended. It can perfectly correct any single bit error out of the 11 bits, but if a pair of bit errors happen within that 11 bit word, all it can determine is that an uncorrectable error has occurred. If 3 bits out of the 11 are in error, the algorithm cannot recognize the situation and the wrong 8-bit word is output. An uncorrectable error is one in which the algorithms has to "fake it" via interpolation, or in really bad cases, shuts down the output.

And it should be pointed out that the original CD was stamped all at once, and NOT spinning at full speed and having the data burned by a laser into a photo emulsive substrate. So, when a CD-R is "burned", we are talking about it first being read at the full 1x speed, and THEN written at the full 1x speed. And there are a myriad of other factors, such as the light passing thru the "decidedly NOT 'optical lens quality' polycarbonate", TWICE (once to read, once to write, with the writing energy level of light much higher than the reading energy level...all at full speed)...the various reflective properties of the gold or silver reflective layer (those are the only two materials used, no CD-R's use aluminum), the various opacity properties of the different dies used in the photo emulsive substrate. And also, how all of this affects the "jitter performance", which as pointed out above, can be both mechanically-interface-related, and also can take place in the digital domain during the data transfer through the circuitry. My point is, there is NO such thing as a "perfect copy" of anything ANYWHERE, simple physics (and the uncertainty principle) dictate this. Also, my brother is both an EE and a computer programmer, and he informs me that a data CD has much higher tolerance for errors than an audio CD, because of the nature of the error correction of the software (it does perform heavy interpolation to correct for errors...no personal computer would function at all, if this weren't the case).

Sorry, but you surely misinterpreted your brother's words. The physical CD-ROM format, IEC 10149, has more error correction levels especially because of the fact that a single, logically irreparable error is fatal to software. CD-ROM error correction definitely does not allow for interpolated data.