Comparing Powerline Ethernet to WiFi for streaming audio


Thought I would share my findings.
I have a ROON based music server system with Tidal and Qobuz streaming services. Using Small Green Computer’s SonicTransport i9 Optical as ROON Core, connected via optical cable to a Sonore Optical Rendu (powered by Sonore Linear Power Supply) acting as ROON endpoint. This then connects to Chord Blu Mk 2 via USB, which upsamples and connects to Chord DAVE DAC via dual BNC.
Until very recently, I was connecting my ROON Core to my cable modem/router using Google Mesh WiFi. I was and still is very happy with the sound quality. My audio system is too far from my cable modem to run an ethernet cable from cable modem/router to it. So, I relied on Google Mesh WiFi with a seperate pod situated close to the ROON Core and connected via ethernet. The Google Mesh pod itself had a linear power supply instead of the stock wall wart.
But I just tried a Powerline Ethernet adapter. This uses the home’s internal power cables to route ethernet from one room to another. I always thought that running digital data on power cables was going to be noisy. I bought a NetGear Powerline 1200 (1200Mbps speed). There are more expensive and newer powerline ethernet models available up to 2000Mbps speed. But these come with dual ethernet ports and pass through filtered power outlets. I though for dedicated audio purposes, better to keep it simple and minimize electronics.
Bottom line, I was blown away by the improvement in audio quality of the NetGear Powerline Ethernet connection over the Google Mesh WiFi connection. Mind you, I was very happy with the quality from the Google Mesh kit but the NetGear Powerline ethernet kit was clearly better.
The sound quality improvement was immediate and very evident. More space between instruments and notes. Smoother, more image depth and more air around the notes especially the trailing edges. So, no doubt, the Netgear Powerline 1200 was far superior to the Google Mesh WiFi. I then swapped the Netgear for a similar powerline ethernet product TP-Link AV600. This was recommended by Small Green Computer. The TP-Link is smaller and has 2 pin power prongs. The Netgear Powerlines has 3 pin power prongs, so it has a ground connection to the power outlet. I found the TP-Link to take a step backward in sound quality. The image depth decreased. Soundstage was flatter and there is less air and space between notes and instruments. The TP-Link Av600 was sounding a lot closer to the Google Mesh WiFi. Just my observations, FWIW.
ddriveman
Further to my original post on the NetGear Powerline 1200 (1200Mobs). I decided to try other powerline ethernet adapters. Thanks to Amazon, I ordered the Zyxel G.hn 2400 wave 2 powerline adapter. This is the fastest powerline adapter I can find 2400 Mbps) and uses latest technology G.hn. I also ordered the TP-Link AV2000  (2000 Mps). Both the Zyxel and the TP-Link have pass through filtered power socket and 3 prong sockets.
Note that I am on COX ISP with 1000 Mbps service although the max speed I can get is around 750Mps only. So even my NetGear Powerline 1200 is theoretical already exceeding what my ISP can provide.
Findings:
1) Zyxel G.hn 2400. At first, I thought this was sounding better. It seems cleaner, quiter, more focussed. But further listening showed that it truncated the trailing edges, less air, smaller soundstage. It sounds flatter and more "hi-fi" but less organic, less natural than the NetGear 1200. When I switched back to the NetGear 1200, I heaved a sigh of relief. The music was flowing better, wider+deeper soundstage and more air with better timbre and texture. So the Zyxel is being returned.
2) TP-Link AV2000. I was not able to connect this to my music server. For some unknown reason, my music server won't sync to the TP-Link although I confirmed that internet was connected and present. The ethernet sockets on the TP-Link seemed tighter/smaller than normal. My audiophile ethernet cables have large connecters and don't have a definite click when inserting. It's probably something to do with these ethernet sockets. I was not going to try to listen to it with standard ethernet cables. So, the TP-Link is bring returned 
Finally, I have also moved my cable modem, wifi router and ethernet switch to a audiophile linear power supply from iFi iPower power supplies which yielded a small sound improvement. This was done before reviewing the powerline adapters. FWIW

@ddriveman Thanks for your post.  It was very helpful to me.  I had the exact same experience you did.  My wifi streaming sounded lovely, however an internet tech (after installing Fiber) recommended I try Powerline adaptors.

First I tried the TP-Link AV1000 Powerline Ethernet - the sound was noticeably constrained, veiled, more harsh and less engaging than wifi.  Soundstage much smaller than Wifi.

Then from your post, I tried the NETGEAR Powerline adapter Kit, 2000 Mbps Wall-plug.  A noticeable increase in bass and treble definition and depth, clarity and microdetails.  Soundstage slightly taller than Wifi.  A nice improvement, and worth the $70.

This was all through a Bluesound Node 2, with Apple Music Lossless Airplay as a source.

Again, thanks for the tip and hopefully this is helpful to others!

I have my audio system connected to my router via a 50 foot CAT6 ethernet cable.  I use Powerline adapters for my TV setup which involves an outdoor antenna and a Tablo over-the-air DVR (works fantastic, BTW, as long as you have a really good antenna signal feeding it).

It very well may be a placebo effect, but my audio system sounds harsher (even with vinyl) until I unplug the Powerline adapters.  I do have an Audioquest Niagara power conditioner....

I also like to turn off my hot tub and fridge at the breaker box and make sure all dimmers are off before doing any serious listening.

I have thought about doing an experiment by running a temporary long coax cable inside my house and put my modem and router closer to my audio system, the theory being that it might be better to have a long coax run and a short ethernet run.  A similar theory to having my monoblocks right behind my speakers?  I'm using .5 meter speaker cables and roughly 4 meter interconnects from preamp to power amp

@boulder_bob I recently moved to a new room where it was not convenient to use a wired Ethernet connection, and it was recommended that I use a wireless extender instead. I did this and everything worked fine. One day I decided to see if a hard wired connection would sound better, so I ran my 30’ BJC Cat6 cable through the house to the router. The change was significant and not in a good way, the black background was now more gray. I reverted back to the Tp-Link extender and all was well again. My conclusion is that even well shielded Ethernet cables act as big antennas and collect noise. Try an extender, or insert an optical run and a short Ethernet cable on the system side. I think you will like the results.