Why are digital streaming equipment manufacturers refusing to answer me?

Thyname it’s the select dac with the same interface you describe. Since I am receiving bit perfect signals nothing happening prior to the conversion to fiber matters IMO. If the signal was not bit perfect (msb offers an extensive test) then it could have affected things. 

Jmphotography, in the system you describe there is no fiber optic blocking all noise and as a result I completely understand that there could be improvement with a good streamer. Thank you for that feedback.

yyzsantabarbara from what I can tell this would be a good choice and a less expensive way to get bit perfect signals. If the dac is equiped for it the cost is minimal and one can run very long fiber optic cables. If the dac can’t I have read of people buy converters back to usb right before the dac and again get great results with a very short usb cable in the end. M. 

Some clarifications
1) the fiber optic cable is what carries the signal. This provides even greater isolation than a cat cable, in fact as far as I know perfect isolation
2) the double blind tests included four people not just myself including a dealer who had to admit the lack of any difference

Someone referred to blanket statements not being helpful. I am not making any such statements. I am making a hypothesis, I test it, and I ask the community here to help with additional knowledge. 
My thanks to those who have responded on the topic.

Jdt1, why are a b tests becoming irrelevant? Any of us who have read o toole’s book consider his work to be seminal in helping understand real differences but is there something more recent that suggests a b tests if properly conducted include bias? Thank you.

One designer of streamers confirmed that his effort is to reduce any emissions via air, cable and power. My “strawman” above addressed cable. I don’t know about air especially since fiber allows us to move the streamers or NUC as much as a kilometer away! About power however I get the point. That could have an effect. The way I may have indirectly dealt with it is that I run the custom nuc with a linear power supply (150$ from China!) and I always isolate my front end (other than the nuc) with isoclean or balanced transformers. M. 

Hi Welcher. My understanding is that Ethernet sends in packets but since it is still an electrical signal it is possible it would affect sound although a well designed interface is unlikely to. Usb connections are proven to make a difference good or bad with measurements. 

Hi kijanki, thank you for the clarification which I understand. 
My statement was a straw man assumption which I put forward for us to debate. It is “absolute” on purpose, like a math equation that we are trying to prove wrong. Sorry if I wasn’t clear about that and it sounded like I was saying that I know it is correct. Which I don’t.
The revised statement which is now informed by further feedback from two designer experts is that so long as we receive bit perfect signal via fiber optic cable through a converter that is clocked to the dac we get a signal that can’t be improved with expensive streamers. One said “everything before the conversion doesn’t matter at all”.
Some other arguments against this include that one may be introducing electrical noise to the house’s electrical system before the fiber and also that one may be introducing airborne ref. I suspect these are negligible in real life conditions especially as one can move the server to another room.

I repeat this is an assumption for debate although we now have many facts in its favor. And I hope it helps people save money and focus their spending on equipment that matters. 
What I am baffled by is 3-4 responses which were not only rude but also paradoxical: bashing an effort to emulate the scientific method whilst using such science based equipment. Maybe it’s the snake oil they put on their salad. 
All the best and thanks to those who tried to explain and help. M. 

Also reading the earlier confusion about fiber optic. My bad, I didn’t want to detail the system and I should have had. I receive streaming via fiber and also play audio from local drives. All this is irrelevant to my point. My reference to fiber is only as it relates to what happens between the Roon core and the dac. My Roon core is home made and via usb it goes into something called usb pro which is basically msb’s conversion from usb to fiber optic cable. This cable then feeds the dac directly. I was only referring to this connection and not to the ISP. My understanding is that usb pro is clocked to the dac’s clock. And my search has been to figure out if I can improve on my home made nuc with expensive or well reviewed streamers. Stereophile just had such a review where the writer who seems quite honest clearly says that he can’t ascertain any audible differences. 

Btw the designer of maybe the best steamer finally confirmed my straw man assumption. Turns out indeed it was correct. The signal is identical. No one can hear any difference.Of course I wouldn’t question that the person who was very offensive for no obvious reason earlier would hear differences from these identical signals from up there at his high horse. M.

Thyname thank you for the more extensive response which I hadn’t seen until now. Going for that bath now! M.

I assume you meant prousb and not usb? Did you run bit perfect tests to ensure you were comparing apples to apples? 
It is encouraging to hear you got improvement and that it was pretty simple. Would you mind elaborating how you can intuitively figure out the reason based on what the innuos statement has / does? 

Some really good points about A B which I will address here. Since someone attacked my person for some mysterious reason, I am forced to explain that these tests were always done with a group of experienced audiophiles in Asia and in Europe. To them we added some friends who aren’t audiophiles to make sure we don’t have any bias from that. We did double blind tests, not triple blind. The groups were not the same always. And the tests were two hour affairs on occasion and not some extensive lab test. I am claiming nothing other than what this meant for us. 
The post earlier about how the ear isn’t made to compare is I believe correct but our methodology probably eliminated this bias. 
First we listened with knowledge of what equipment we are hearing. Then we listened to equipment which was given a code (not A or B but eg 346 and 589). And finally we listened to unidentified equipment in random order and asked to identify which code it was. 
Various pieces of equipment had different success because many obviously do sound different. But with equipment which shouldn’t really make a difference according to some logic, we had the following results

1) consistently, expensive equipment was identified as better and we could all elaborate that we heard specific differences. I certainly did think so

2) consistently, when the equipment was labeled, we could not necessarily say if it was overall better or not than the other but we developed certain characteristics we each thought we heard. These characteristics were not consistent between each listener but the same for each listener

3) not one person was able to identify these differences with more than 20% consistency vs 1 or 2!!!

Take me out of the equation since I am apparently a troll. The people in these rooms are audiophiles with significant experience, from different cultures and of different ages. We were stunned. (Non audiophiles usually abandoned us after 30m).

What this meant for us? If we smell something doesn’t make sense, we look into it so that we don’t end up spending our savings towards the wrong equipment or system. Ie we try to reduce bias. As a result we feel we have better systems with less equipment and less cost. 
This is how this worked for us. I am sure everyone has their way and I am not making any broad généralisations about anyone else. I did feel validation when I read the seminal work of o toole and some sites which do measure equipment extensively with correlation to performance potential. 
To each their own, although I hope at least some of you may consider these points.

troll out!

Thyname you wrote feeding via usb and I wanted to be sure that the prousb conversion was involved. So if you know more about how your streamer would improve the signal it would be great to hear it. It goes against what msb and other steamer makers are saying but maybe there is something they are missing. I haven’t had the opportunity to listen to this steamer, looks terrific.

kijanki much appreciated. Exactly, I am focused on the fiber connection because it eliminates all electrical interference. What I struggle with is that since the signal is bit perfect and the fiber eliminates noise which would have affected the dac, wouldn’t we be getting data = what was sent? Thanks again, getting late here in Europe. 

Audio2design, I couldn’t agree more.