"Audiophile Grade" Ethernet Switches - The new generation

[David A]

While we're swapping incredulity: another interesting story on the AS thread(s) (I can't remember which one exactly) was the debacle about the v2 firmware.  To summarise, among all the glowing initial reports there were a few people who reported drop-outs with the ER in place.  Turns out that this was an engineering mistake to do with support for Energy-Efficient Ethernet, which was fixed by a firmware update.  No problem, it's a new product, and these things happen...

Then there was a stream of reports that the new firmware caused the ER to sound significantly worse than the original firmware.  We then had the very peculiar situation where Superdad on that forum, who I understand is the owner/boss of UpTone, said that people couldn't trust their listening tests between v2 and v1 firmware, because their aural memory was too short and they were in reality comparing the new firmware with what they *thought* the old firmware sounded like, and that was not a valid basis for comparison.  I'll leave you to ponder the irony of that.  Really, you couldn't make it up.

(Needless to say, if anyone thinks I've misunderstood or misconstrued what happened, let me know.)

Is the issue here the fact that some people think the sound changed with the firmware change or that Alex Crespi discounted the reports of a change in the sound by questioning what the claimants said they heard, or both? Throwing stones at reports of listening experience is easy. 

Let's look at Amir's report of his listening test of the ER in his review at https://www.audiosciencereview.com/forum...iew.10232/

His process:

1- connect both his generic cheap switch and the ER to the network;

2- connect a cable to the B side of the ER and another cable to a free port on the cheap switch;

3- connect the cable from the cheap switch to the ethernet port on his DAC and start streaming some music;

4- while the music is playing, disconnect the cable from the DAC and connect the cable from the ER to the DAC. The music continues playing without pause because there is a big enough buffer in the DAC to allow time for the cable swap before the buffer empties;

5- after listening to the ER for a while to see if he noticed a difference (he didn't), then repeat the cable swap procedure again disconnecting the ER from the DAC and reconnecting the cheap switch before the buffer empties and keep listening to see if he notices a change on this swap. Again he doesn't.

What can I say when he's reporting this in what's supposed to be an account of a reliable test of the ER? First we have a sighted test, he knows which DAC is connected at all times and sighted tests are always suspect or so we're told. Then he has to break his listening concentration while he manages the cable swap so there's a break in his attention when he makes the cable swap and that can change his perception. Then, he has no idea when the buffer will run out and the sound swaps from coming from the signal from one DAC to the signal from the other DAC so it's possible that he's reaching his decision on whether or not there's a difference while he's still listening to the signal from the previous DAC before the data from it stored in the buffer runs out so he could be comparing the sound of the previous DAC to the sound from that same DAC because he can't be certain when the change in signal occurs. Finally he presents the listening test" data after presenting the dara from the other tests he conducted which suggests that he conducted the listening test after doing measurements in which he found no difference between the ER and the cheap switch when it comes to jitter, noise, distortion, clock speed, or output voltage so he will have an expectation bias that there will be no audible difference.

And then he says that if you hear a difference  you should repeat  his test with someone else swapping the cables behind your back (i.e. conduct a single blind test) and do 10 trials and see if you get it right better than 8 out of 10 times. In other words,he's telling you thatyou can trust him on a sighted test of less than 10 trials when he almost certainly had an expectation bias that there would not be a difference but you can't trust yourself on a similar test and for your results to be reliable you need to do at least a single blind test of at least 10 trials.

Yes, Alex Crespi's response about the the comments from users about hearing a difference in the firmware versions doesn't make sense, especially when he was happy to accept the initial favourable reports from the same owners, but Amirm's listening test and and his assumption that he can be relied upon to get it right on a poorly designed and conducted sighted test but that anyone who doesn't hear the same thing as he did needs to do at least a single blind test over multiple trials, a test he doesn't think he needs to do to get a reliable result, doesn't make sense either.

I'd give them both a fail on this aspect of the discussion.