…..sometimes science hasn't yet formulated the right questions to ask, in other words fails to devise measurement protocol to account for what we hear
+1 @sns seasoned audio engineer John Curl said the same thing
How can different CAT5/6 cables affect sound.
While is is beyond doubt that analog cables affect sound quality and SPDIF, TOSlink and AES/EBU can effect SQ, depending on the buffering and clocking of the DAC, I am at a loss to find an explanation for how different CAT5 cables can affect the sound.
The signals over cat5 are transmitted using the TCP protocol. This protocol is error correcting, each packet contains a header with a checksum. If the receiver gets the same checksum then it acknowledges the packet. If no acknowledgement is received in the timeout interval the sender resends the packet. Packets may be received out of order and the receiver must correctly sequence the packets.
Thus, unless the cable is hopeless (in which case nothing works) the receiver has an exact copy of the data sent from the sender, AND there is NO timing information associated with TCP. The receiver must then be dependent on its internal clock for timing.
That is different with SPDIF, clocking data is included in the stream, that is why sources (e.g. high end Aurenders) have very accurate and low jitter OCXO clocks and can sound better then USB connections into DACs with less precise clocks.
Am I missing something as many people hear differences with different patch cords?
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@panzrwagn Is error recovery instantaneous? If you read my post, I'm not talking about errors in the data. I’m talking about the timing of errors. |
Calling John Curl a "seasoned audio engineer" is like calling Robert de Niro a longtime member of the Actors Guild. Neither is objectively false but both miss reality by a mile and a half, which is in keeping with a lot in this thread. @kennyc can you kindly provide a link to the John Curl quote?
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@calvinandhobbes if there are no errors, then their timing does not matter. |
@calvinandhobbes No, recovery is not instantaneous, nor does it need to be. The incoming packets are stored in a buffer then released when the error-checking/correction is complete. This is a continual ongoing process measured in milliseconds, and the buffers are sized to accommodate almost any conceivable requirement or packet loss short of a complete failure, so unless there is a calamitous event, the entire process is transparent and the buffer output is seen as continual. TCP/IP does exactly the same thing, independent of the physical media or wireless transport. |
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