Sound quality differences between NAS units

[skeptic Mike]

(20-08-2016 07:13)simoncn Wrote:  The audio data is transmitted using TCP and there is no doubt that in all cases the renderer has received an identical copy of the bits sent by the server. The discovery protocol uses a mixture of UDP and TCP.

If this is the case, then the fault must lie in the renderer or in the subsequent amplifier or loudspeakers. Now the renderer is a small computational device which must contain its own clock that drives its switching circuitry, and I find it hard to see how controlling this "noise" could be possible, but that noise from the Ethernet or wireless could get through. Digital audio is based on mathematical theory which shows us that we should be able to reconstruct a bandwidth limited digitised signal correctly, i.e. for any given digital stream there is one correct analogue output.

So, I think that winxi is right and these are differences in human perceptions. If I'm wrong, then either much "Hi-Fi" equipment is badly implemented, and that's the problem, but because noone measures or tests it we don't know this. Or there are effects that we can't measure or explain, which makes designing the equipment hard, and also means that the manufacturers of our audio equipment have no useful method of ensuring sound quality control, if they can't take a sample device and perform objective tests on it to check that it meets its sound quality specification.

But I know we'll never agree about this, so I should be happy that I can enjoy listening to streamed music through a basic Sony Blu-Ray player, and an equally basic Yamaha amplifier with built-in DAC.