I'm creating a new thread here so as not to crap on the 'Any Roon users' thread I posted my review of Roon on a few days ago with my footnote voicing my concerns over the audio quality I was getting via streaming over Roon.
To summarise, I have a dedicated audio PC setup which is a mini ITX board with an i5 processor running a headless Ubuntu server off an SSD with all of my music on a 2TB hard drive. This sits in a room next to my router connected via Ethernet and all that this server runs is Roon server and Plex for when I want to stream a movie to the TV downstairs. My endpoint for Roon is a Raspberry Pi 3 with Piano DAC and KALI reclocker - A combination I know to sound VERY good when fed with a good signal. I had become a bit disillusioned with Roon having replaced the SD card in the PI with an installation of Volumio and started using Spotify connect through it which I'd been thoroughly enjoying. Fair to say it had me listening to lots of music again, where by comparison Roon streaming to the Pi from the server was sounding flat and lifeless with no sense of timing so I just wasn't enjoying music from it. My review saying so, put me into action to try and find out where things were going wrong:
The first thing to do was to rule out that Roon was at fault - which I did.. Also, that it was not a problem with the server hardware (I had suspected the tiny fanless Pico PSU may not be man enough for the job but then this server is barely lifting a finger). I spent a night with the PC next to the hi-fi and had it connected directly via a USB DAC. I was up pretty late listening to music from it so that told me that the problem HAD to lie somewhere on the network. Nothing wrong with Roon, or the PC it's playing from.
Next experiment - To take the whole thing off the main network and try it on a separate one. I had a spare and very old Apple Airport extreme doing nothing so I hooked that up, made an unsecured wireless network out of it, connected both the server PC and Pi over wired Ethernet and controlled it from my Mac on a wireless connection. Bingo - That sounded ace. I then tried disconnecting the Pi from Ethernet and set it up over wireless to mimic the setup from the main network - Still sounded great, in fact, I could tell no difference to the Ethernet connection. So why does it sound crap from the main network?
OK, let's try removing all of the other devices from the main router - Which is a Netgear D7000, not a cheap router: There were quite a few devices to disconnect - TV, Apple TV, 2 x tablets, and 4 x phones, and yes, with just the Pi, server and one PC to control it all with attached to the network, things certainly did sound better - But still not as good as with the Airport Extreme.. So what's different here?
Ah yes.. The main network has wireless security switched on - The network I set up on the Airport does not - Let's try switching on encryption: Interesting - That has killed things off a bit. Everything sounds a bit more shut in. It's still not as bad as the Netgear, but there's a noticeable difference...
I have an iFi 12V power supply I can try on the Netgear router, let's see if that makes a difference: Marginal at best, it's still not great.
So it seems that there is something that Netgear router is doing that kills the music. I've even tried running a long cable from that router into the pi, so there's no wireless involved, but it's still nowhere near as good as the old Airport router.
I've been through a load of configuration settings in the Netgear router and listened for differences, but nothing seems to make a difference, so what is at play here - Is it just that it's not a very good router for audio use, or is it that because it's dealing with the incoming internet connection that that is having a detrimental effect. The Airport unit is not a DSL router so I can't make any comparisons there.
Here's another confusing element just to muddy the waters that bit more... All of my testing initially was done with my Volumio installation that I had piggybacked the RoonBridge software onto. I later realised that the streaming was being done in Airplay mode rather than using Roons native RAAT audio transport, so I went back to my original dedicated RoonBridge SD card... And where I'd had everything set up and sounding great with the Airport router and Airplay playback, it fell flat as a pancake again.. This is getting confusing.
So current options are - Stick with separate dedicated audio network, the Pi and use the Volumio card and airplay streaming, which sounds great but loses me hi-res playback (not a massive issue), or move the PC next to the hi-fi permanently and just run it with a DAC connected to it directly. I'm going to need to make its fans a bit quieter for that, but at the moment, this is starting to feel like the way to go given my new found concerns about audio over networks...