Reference Transports: An overall perspective

As you know any computer today can play a CD/DVD. But a CD/DVD player does not have to be as complex as a computer. A CD/DVD player does not require an operating system. However, it does have firmware, i.e. software which runs the hardware. Dont forget that all CD/DVD players are digital systems anyway so they already have RAM memory. If properly designed, a CD/DVD player can offload all data into RAM prior to playing the music hence relegating the responsibility of the transport to merely a temporary storage for the music. Furthermore once the data has been offloaded into the RAM buffer, the transport no longer has an effect on the quality of music. Just think of the CD/DVD disc as inexpensive storage and the transport as a means of transfering the data on the CD/DVD to digital circuits. You can decouple the processing from the storage (the disc) by using a RAM buffer for intermediate storage.

Lktanx, so if error correction is only for gross errors, then it seems logical that the transport becomes a very important part of getting the data correct, particularly if it can minimize the random errors that occur in all physical systems. If errors are correlated, then adaptive error correction would be helpful, but how are random errors corrected once they occur?

I agree that once the data is read to RAM, the only meaningful influence on the digital signal, other than digital filtering and D/A conversion, is the precision of the clock. Still, to get the data into RAM you need to read it via a transport, and unless you're claiming that all transports are perfect, I don't see how the transport is not a meaningful link? We could debate the significance of this link, but that's another issue altogether.

Transports are not perfect i.e once in a while they make errors but these errors are detected and corrected by a digital circuit. If the system makes a huge amount of errors, such as when your car CD player skips when you drive thru a bump on the road, then you will hear this. A skipping CD player is an example when too many errors are made which "overloads" the error correcting capability of the circuits.
Note that we a talking about a digital means of data delivery. This is not an analog system like a turntable where subtle issues i.e. spin rate of the turntable can be coupled into the music. The digital system with transport is tranferring 1's and 0's into RAM. It does this with the utmost reliability. Dont forget you are trusting such a system of data transfer when you use your computer on a daily basis.

Germanboxers, I would like to emphasize that you are right; the transport is very important. It is responsible for getting the data correct. However, getting the data correct is very easy and very inexpensive and very trivial. All PCs today rely heavily on CD/DVD transports doing their job well. In a PC, when a transport fails, you throw it in the trash and get a new one.

Lktanx, you do understand that a digital bitstream is just a voltage (analog) approximation of a series of square waves representing the "1" and "0"'s? It's not just mathematics.

I was not referring to massive errors resulting in skips, etc. What I was referring to was the fact that all physical systems exibit some degree of random variation (random error for sampling systems) and these non-correlated errors cannot be "corrected". The question that neither of us can answer conclusively is to what degree does a transport that exhibits less random errors have on the final sound quality?

Ram buffering makes a great deal of sense...on that we agree completely!! Why do you suppose a company like Esoteric has gone through the trouble and expense of developing an incredibly massive and robust transport (VRDS Neo) for exclusive use in players that also SRAM buffer the data? I certainly wouldn't offer this as "proof", but it is interesting that over half the cost in their machines is taken up by the transport mechanism...and all of them read the data to SRAM. It would be interesting to be able to take two of their machines, pull the VRDS Neo out of one, stick a CD-ROM transport in it, and compare the sound side by side.

Anyway, interesting discussion. As an engineer, I'm somewhat baffled at times by what can make apparently meaningful changes in the sound I hear. I'm equally baffled by some of the absolute crazy stuff being peddled by some as well.