Networking-for-audio-performance questions

[fzman1956]

This post is my attempt to combine a number of questions/concerns about how to get the best sound out of networked audio--without spending a fortune 'buying and trying'. I'm running Roon core on my desktop PC, pulling files from a NAS, feeding 4 zones.  My internet is 150G Xfinity, and I live in a house by myself.

 

 I don't expect to get a concensus on all of this, but would love to hear what's worked (or failed miserably) for people, and what some of the real theory behind these things might be. It will become clear that I am not an EE or a network engineer, so forgive me in advance if some of these questions are naive/wrong-headed, but it is useful to understand how I may be relying on an incorrect picture/model of how these things work.  I also believe that the stuff in the basic textbooks is not always the whole truth either.  Here goes, in no particular order:

 

1.Switches, beside # of ports, and managed/unmanaged, what matters for performance?

 

2. I've built but not yet tried some of the JS grounding adaptors, but also have a few metal-cased switches that have grounding screws.  Should I connect their grounds as well?  Should I do this for every wallwart powered network device in the whole network?

 

3. I have an ASUS AC88U router with a built-in 8 port switch- will it matter whether I use all 8 ports, feeding other switches as necessary, or should I offload the switching functions from the router as much as possible? Is it good/bad/neutral to have data/music flow through mutiple switches, vs a more direct path?

 

4. Ethernet cables: Is anything above CAT6 enough?  Shielded vs. unshielded? Proximity to other cables - AC, e.g.?

 

5. Will LPS's work better than SMPS, for all of the networking hardware?  

 

That's it for now.  Thanks in advance for your replies.

 

Mark

 

 

 

 

[wklie]

For the purpose of Roon, it's best to use an unmanaged switch, because there have been multiple reports of problems with a certain popular brand of managed switches in Roon forum.

 

Check our Roon knowledge base on sound quality:

https://kb.roonlabs.com/Sound_Quality

[mansr]

33 minutes ago, wklie said:

For the purpose of Roon, it's best to use an unmanaged switch, because there have been multiple reports of problems with a certain popular brand of managed switches in Roon forum.

Why don't you mention which one this was instead of declaring all managed switches bad. I doubt there would be any problem with one from, say, Cisco.

[Miska]

2 hours ago, mansr said:

Why don't you mention which one this was instead of declaring all managed switches bad. I doubt there would be any problem with one from, say, Cisco.

 

Cisco is especially one of those, but enabling the 802.3x flow control from the settings solves this (disabled by default). Took fairly long thread before it was figured out what was the culprit.

 

Some of the HPE switches have 802.3x enabled by default, so slightly less likely to encounter problems with those.

 

Most or all unmanaged switches either forward or support 802.3x, that's why it is typically less problematic. HPE and Zyxel for example explicitly declare that they support 802.3x on their unmanaged switches. With managed switches one just needs to pay some attention into configuration, not necessarily being correct by default... So buying managed switch and using it like unmanaged on is not so great idea.

 

 

As discussed earlier, one problem is because faster networks can overwhelm interrupt handling capability of software stacks in many lighter networked audio devices, leading to lot of retransmissions which makes things just worse. These devices rely on the ethernet adapters' built-in 802.3x to control the packet inflow when their network packet buffers run out. Popular SoCs tend to have for example gigabit MAC, but local bus to CPU is only capable of about 400 Mbps speed causing lot of packet loss when MAC is not able to stop the packet inflow.

 

[Miska]

16 hours ago, fzman1956 said:

1.Switches, beside # of ports, and managed/unmanaged, what matters for performance?

 

Support for 802.3x (flow-control), 802.3az (energy-efficient ethernet) and 802.1p (CoS).

 

Also proper metal case (forget plastic affairs) and built-in PSU with 3-pin IEC power connector (forget wall-warts).

 

16 hours ago, fzman1956 said:

2. I've built but not yet tried some of the JS grounding adaptors, but also have a few metal-cased switches that have grounding screws.  Should I connect their grounds as well?  Should I do this for every wallwart powered network device in the whole network?

 

It depends, but if there's a wall-wart and it has grounding screw, then it may be advisable to use it.

 

16 hours ago, fzman1956 said:

3. I have an ASUS AC88U router with a built-in 8 port switch- will it matter whether I use all 8 ports, feeding other switches as necessary, or should I offload the switching functions from the router as much as possible? Is it good/bad/neutral to have data/music flow through mutiple switches, vs a more direct path?

 

Usually normal switches are better, but it depends what you replace it with. Likely not worth replacing it with some other wall-wart powered unmanaged thing.

 

16 hours ago, fzman1956 said:

4. Ethernet cables: Is anything above CAT6 enough?  Shielded vs. unshielded? Proximity to other cables - AC, e.g.?

 

CAT6 is just fine. And absolutely unshielded ones (UTP). Shielded (STP) types connect grounds/chassis of devices together causing ground currents and breaking one of the great capabilities of Ethernet which is galvanic isolation (signals on Ethernet are transformer isolated).

 

16 hours ago, fzman1956 said:

5. Will LPS's work better than SMPS, for all of the networking hardware?

 

No, even wall-wart powered ones likely have switching regulators inside anyway. And it really doesn't matter for networking gear anyway.

 

 

What I do is that I have two power filters, one where all equipment with SMPS are connected, and another one where all equipment with LPS are connected. Problem with SMPS are more the junk they push back to power network rather than on the low voltage output side.