Ars Technica promoted the following comment to this post about Sony's new audiophile microSDXC card which will hit Japanese-only shores soon enough.
“Okay, everyone here needs to take a step back. I am an actual analog circuit designer, so here is my take:
First of all, let me start by saying I’m sure, just like everyone else, that these devices have no practical effect on the audio produced by pretty much any practical system. That said, people seem to be confused about the nature of noise in a system.
As the story correctly notes, digital systems are inherently noise resistant, and often include error correction. There is no SD card or cable in the world that will help improve digital transmission if all the data is already being successfully transmitted. However, analog systems are susceptible to noise. In fact, a significant amount of analog design is dedicated to dealing with noise. In addition to random noise, which is introduced by thermal movement or other random processes in the devices, analog signals are also susceptible to interference, or other nearby signals which can corrupt the analog signal. Nearby electromagnetic fields can couple to analog traces on the board, degrading performance. A significant effort goes into carefully routing and shielding analog traces, as well as moving sources of interference further away.
High speed digital systems are a large source of interference. The fact that digital systems involve several wires switching at “full swing” at high frequency means that it produces a comparatively large electromagnetic field in the immediate vicinity. Again, a significant effort goes into keeping digital and analog components apart from each other in high quality audio systems. If your analog trace goes next to a memory running at hundreds of MHz, it will effectively increase the noise floor of your audio.
It is conceivably possible that Sony actually did design an SD card which generates less electromagnetic interference (EMI). This could conceivably lessen the amount of interference coupled into an audio signal somewhere. That said... it’s not going to make any difference in reality. If the SD card noise was having a practical effect on your audio then the whole systems was crap to begin with. So, as I think everyone in this thread can agree, this is snake oil.”
And there really is nothing left to say until Sony get into the business of making porper hi-end ethernet cables.