Objective-Fi Optical Networking & SFPs

[The Computer Audiophile]

Hi Guys, this is an objective topic to look at the assertions made by some that SFPs make a sonic difference in audio systems. I'd like to use real science and a real scientific approach in this one. This means, we may have a belief one way or the other, but we should go into this with an open mind and follow the available objective evidence. 

 

@jabbr's thread on optical networking is what made me think of creating this topic. That thread is much more subjective and I know others have objective comments they'd like to put forth in this discussion. 

 

Here is Jabbr's thread - 

 

 

[The Computer Audiophile]

1 minute ago, cjf said:

I'd be curious if anyone has done any bench testing using an analyzer of some kind to see if the SFP's generate any more or less noise than a regular eth nic does. It certainly makes me wonder why almost no manufacturer of high quality dacs has gone down the fiber direct route to dac yet. I believe there are a few that have used the fiber direct to dac connection like Meitner and Bel Canto but they are the only ones that come to mind.

 

It seems like a no brainer to a simpleton like me to try and use a fiber direct solution to a dac due to fiber cables baked in electrical isolation but I'm clearly missing why it hasn't caught on yet. I mean in the IT world fiber usage is everywhere and has been for many, many years so there is nothing really untested or new about the technology itself.

 

Short of the electrical isolation part of fiber I see no other reason to use it for home audio purposes unless one stores there computer, nas or streamer in a neighbors house hundreds of feet away or a few km away in the next town over from the listening room. I also see zero reason to use it for speed reasons as 1gb regular nics are already super overkill. And then I've seen some going 10gb for audio which can't be for anything but bragging rights or just out of curiosity as a project in ones spare time, which of course is perfectly fine if that's what interests the person doing it.

 

I would certainly love to see it catch on with dac manufacturers but it seems the industry  just ain't there yet or perhaps ever will be

EMM and Bel Canto use audio over optical connections, not Ethernet fiber connections. 
 

Lumin’s X1 has an SFP slot that I used during my review. Good stuff. 

[The Computer Audiophile]

32 minutes ago, plissken said:

WiFi offers just as much isolation while providing more than enough throughput on 5G / 80VHT

That’s a great topic for another thread. 
 

WiFi devices that let the user control the channel width are great. Heck, my UniFi stuff goes to VHT160, but I have nothing that can use that. VHT80 is great as long as the environment is great. 

[The Computer Audiophile]

2 minutes ago, plissken said:

VHT 80 is recommended for Greenfield installs. Especially if you can use DFS channels.

DFS will stop working in the presence of radar though correct?

[The Computer Audiophile]

5 minutes ago, plissken said:

 

Sure. Would you take a ADC capture of a recording where I swap out cables during playback?

That won't address the SFP question though. 

[The Computer Audiophile]

7 minutes ago, plissken said:

 

Why wouldn't it? You can only hear a difference if the output of a DAC is altered. I'm offering a way, just like Alpha Audio on YouTube did when they tried six different Ethernet Cables.

You would need to switch SFPs if the hypothesis is that SFPs sound different. 

[The Computer Audiophile]

18 minutes ago, plissken said:

 

Solar Flare adapter has an easy to use Teaming GUI. I can put an FS and Finisar SFP+ module in side by side and simply disconnect at the switch while music is playing.

 

Also Windows 10 features by default SMB multichannel if we want to dispense with teaming the NIC.

That wouldn’t isolate a noise SFP 100%. 

[The Computer Audiophile]

37 minutes ago, plissken said:

 

Why not. We are unplugging the cable. We could instead unplug the adapter.

You would need to unplug the adapter. 

[The Computer Audiophile]

As the OP of this thread, I ask that the nonsense be stopped. This thread is in the Objective-Fi sub-forum. Please stay on topic and strive for objective information. 

[The Computer Audiophile]

On 6/18/2020 at 3:16 PM, plissken said:

Correct,  it will channel hunt and hop. But you should be able to see DFS alerts in the controller.

I was thinking about this over the weekend. I know, that's what I do and it's ridiculous. At least I was sipping the tea you sent me while doing it :~)

 

I can't wait for us audiophiles to start comparing the sound quality of WiFi frequency bands and channels. If we can't make fun of ourselves, we are in trouble :~)

 

P.S. I'm a card carrying, knuckle dragging audiophile and include myself as the target of all jokes I make. 

[The Computer Audiophile]

10 minutes ago, bluesman said:

The problem with most amateur DBT is how it’s done, not the principle behind it.

100% true.

[The Computer Audiophile]

14 minutes ago, bluesman said:

To bring this back OT, well done DBT could help determine if network platforms and components make discernible difference in SQ.

I suppose we would also have to include in that statement, well done DBT could help determine if network platforms and components make discernible difference in SQ, to those tested.

 

There will always be people who, either real or not, believe they are outliers or different from the test group and the results don't ring true for them. 

[The Computer Audiophile]

4 minutes ago, bluesman said:

And there really are a few clinging to each end of the bell shaped curve.  But most of us are like most of us. Only in Lake Wobegon are the children all above average.

Agree. Plus, I live close to Lake Wobegon :~)

[The Computer Audiophile]

2 minutes ago, jabbr said:

reasonable theory however,

 

1) the lines to/from the SFP(+) are differential, so constant current.

2) compliance testing for 10Gbe+ disproves significant ground bounce

 

so available measurements fo not support thus theory, nor have I seen measurements of legacy 1Gbe SFPs which demonstrate this.

 

That said I would be surprised if a generic SFP or NIC failed to meet the standards ascribed to by major manufacturers. For me the differential cost of going with a well known manufacturer is low enough that I do that and don’t worry about this.

Are there links to any of that, that I can read up on?

[The Computer Audiophile]

I started a topic on buffers and streaming audio to endpoints that I think will be a good discussion with many of the folks in this thread. I can't say where the thread is going, but I think this is an interesting topic.

 

Here's a link.

 

 

[The Computer Audiophile]

42 minutes ago, plissken said:

 

But yet you are going to hear audiophiles opine about how great this sounds and if an objective person points out the obviousness of it there will be a backlash for questioning.

Are you suggesting your feelings will be hurt because of the backlash? 😁

[The Computer Audiophile]

1 minute ago, plissken said:

 

Facts don't care about feelings. Bottom line is you are going to see reviews of this 'Audiophile' device and 'veils lifted', 'my wife heard the difference while down the hall' etc and it's simply an OEM design and they are trying hard to scrub any identifying marks from it:

 

 

 

No disagreement from me. You just brought up receiving backlash.