[mfdoom808]

Well perhaps. I do find the discussion of placebo and confirmation bias on audio forums amusing though as I am a Psychology Professor at a leading European Psychology department and have published peer reviewed papers on cognitive biases. Every time I jump into these threads about tweaks, cables etc I get ‘schooled’ by others about these things or told we should be doing the equivalent of double blinded randomised experiments. Makes me smile - how many actually do that when auditioning hi fi gear ?! I mean I know how to, I conduct experiments day in day out and analyse them using inferential statistics like ANOVA and regression models. Still to me there remains value in subjective opinion.

A long answer to the question, forgive me. So yes, placebo, possibly! Confirmation bias ? No not really as tbh I approached this tweak with a rather sceptical attitude and was rather taken aback by its apparent impact. Is its effect measurable? No idea and the devil’s in the detail of knowing what to measure and then employing suitable methods. Will Amir at ASR measure it and claim it debunked ? Possibly! Will I care ? Nope ! I happily use some DACs that he claims measure badly. They sound great !

As they say, the shoemaker's son always goes barefoot.

 

[Moonglum]

As they say, the shoemaker's son always goes barefoot.

Ha ! Nice quotation

 

[dougms3]

Ethernet is galvanically isolated by design. It's in the 802.3 standard: https://grouper.ieee.org/groups/802/3/af/public/mar00/stapleton_1_0300.pdf

https://www.cisco.com/c/en/us/solutions/enterprise-networks/what-is-power-over-ethernet.html

 

[mfdoom808]

https://www.cisco.com/c/en/us/solutions/enterprise-networks/what-is-power-over-ethernet.html

https://www.silvertel.com/images/appsnotes/ANX-POE-Isolation-Barrier-explained.pdf

 

[vext01]

Irrelevant.

If you plug passive PoE into your PC or streamer, you will fry the device.

If you plug active PoE into your PC or streamer, the negotiation protocol will realise that it isn't a device requiring PoE and not send 48v.

 

[AussieMick]

As they say, the shoemaker's son always goes barefoot.

What do you mean here?

 

[AussieMick]

How convenient!

Well, if you can put aside the cynicism and take the comment it on its own merits it might well be true. dCS are saying something related recently, how the signals being dealt with in a DAC are small enough that the noise injected into the system by the measurement gear itself is enough to corrupt the measurement, and that how you design your measurement protocol is essential if you’re to believe your own results.

 

[dougms3]

https://www.silvertel.com/images/appsnotes/ANX-POE-Isolation-Barrier-explained.pdf

The fact that POE exists and use any ethernet cables negates the possibility of an ethernet cable being galvanically isolated.

 

[Davesrose]

I remember iFi responding to some review at ASR measuring the performance of one of their USB noise filters where they said the level of skill needed to get meaningful measurements was very high, even when you have the best possible test gear. I got the impression it was almost as hard to measure products like this as it is to design them in the first place. As I’ve got a large number of iFi products already (along with a couple of LAN iSilencers on order too that I’m looking forward to trying), I have plenty of confidence that they know what they are doing.

In other words, you've bought into their products and have a bias that there should be an audible difference. I'm also seeing some say that there isn't a bias if you first demo something thinking that it won't make a difference. That's still a bias: you're still unconsciously thinking there's a difference because there shouldn't be one. The only main way to eliminate bias in hearing is ABX testing. There was a $1 million dollar prize for being able to pick up the difference between $7,000+ speaker cables vs inexpensive ones, and it was never claimed. Amir is very transparent about what equipment he's using for measuring noise, and at what bandwidths. If they exceed the specs of the protocols of the device itself, then how much more "meaningful" can it be (sorry, I'm going to reject that he's unskilled)? I thought what was most meaningful about audiophile switch vs inexpensive one was that noise levels were the same after flooding a port with same signal (which negates the claim that these devices can eliminate noise from your one "noisy" PC on the same network).

In the end, I can see that folks that believe in their subjective beliefs are going to question measurements that don't see any difference in what is claimed. I know I've been guilty of bias in the audiophile world: it's especially hard with our perceptions because it can be influenced by bias and our physiology of the moment (IE our hearing always changes due to mood, focus, muscle tension in middle ear, chemistry of inner ear). It will continue to be a round robin of skeptics saying "but measurements", audiophiles saying "but I hear", and an impasse because reasons for having adequate ABX tests.

 

[Moonglum]

What do you mean here?

He’s responding to my post where I say I am a research psychologist- so he’s saying I have the tools to scientifically test the efficacy of this device but I choose not to

 

[AussieMick]

He’s responding to my post where I say I am a research psychologist- so he’s saying I have the tools to scientifically test the efficacy of this device but I choose not to

Righto. Thanks. Not my understanding of the saying, that’s all.

 

[rdale]

In other words, you've bought into their products and have a bias that there should be an audible difference. I'm also seeing some say that there isn't a bias if you first demo something thinking that it won't make a difference. That's still a bias: you're still unconsciously thinking there's a difference because there shouldn't be one. The only main way to eliminate bias in hearing is ABX testing. There was a $1 million dollar prize for being able to pick up the difference between $7,000+ speaker cables vs inexpensive ones, and it was never claimed. Amir is very transparent about what equipment he's using for measuring noise, and at what bandwidths. If they exceed the specs of the protocols of the device itself, then how much more "meaningful" can it be (sorry, I'm going to reject that he's unskilled)? I thought what was most meaningful about audiophile switch vs inexpensive one was that noise levels were the same after flooding a port with same signal (which negates the claim that these devices can eliminate noise from your one "noisy" PC on the same network).

In the end, I can see that folks that believe in their subjective beliefs are going to question measurements that don't see any difference in what is claimed. I know I've been guilty of bias in the audiophile world: it's especially hard with our perceptions because it can be influenced by bias and our physiology of the moment (IE our hearing always changes due to mood, focus, muscle tension in middle ear, chemistry of inner ear). It will continue to be a round robin of skeptics saying "but measurements", audiophiles saying "but I hear", and an impasse because reasons for having adequate ABX tests.

As far as I’m concerned I was making a perfectly valid point about the difficulty of measuring the performance of a noise filtering device like the LAN iSilencer. It doesn’t make me biased one way or another, and I’m not expecting to know how the iSilencer sounds in my systems until I try it out, as its effect is system dependent.

Please note this paragraph in the Posting Etiquette section of the Terms of Service for this site:

5. If what you want to post includes words/phrases like "placebo," "expectation bias," "ABX," "blind testing," etc., please post it in the Sound Science forum.

https://www.head-fi.org/articles/terms-of-service.6725/

 

[Davesrose]

5. If what you want to post includes words/phrases like "placebo," "expectation bias," "ABX," "blind testing," etc., please post it in the Sound Science forum.

https://www.head-fi.org/articles/terms-of-service.6725/

Noted, but this whole thread is rife with these words (including folks saying they know what bias is or questioning placebo), does this need to move on to the Science forum? Seemed there was at least a civil discussion of wanting to determine if there's conclusive evidence of an audible difference. If you want to leave it to testimonials then so be it.

 

[vext01]

Sounds to me like the whole forum is set up to discourage the questioning of questionable claims...

 

[Moonglum]

Surely the issue is that it gets tedious to read on every single thread “placebo, confirmation bias, did you do blind tests, can you measure the effect, can you prove it etc”. Accept that testimonials are subjective- we’re adults here and
can make our own minds up about whether to trust a subjective review- we don’t need rescuing by Amir and co - if we want to know how it measured with an oscilloscope we will head over to ASR