Getting things right with network audio - Follow up from the 'Any Roon users' thread

[lovejoy]

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...

[struth]

maybe try a different type of router. its quite possible for the router to cause upset in my opinion. There are many things going on in there. have you tried changing to 2.4gh or 5gh system on router? i found differences.

[Emmings]

Hi

This article may be of interest for your networking conundrums:

https://www.computeraudiophile.com/forums/topic/30376-a-novel-way-to-massively-improve-the-sq-of-computer-audio-streaming/

Basically it suggests that running a bridged network on the Roon server may improve the sound quality rather than going through the router.

Cheers
Dave

[lovejoy]

Thanks Dave - Yes, that was certainly most interesting reading and after quite a lot of re-writing SD cards, re-jigging network cables, running up and downstairs to plug things into different sockets and general cursing, things have taken a massive leap.

So now the PC is back in its original position in a different room next to the router, so no problems with fan noise anymore. The Airport router has been bridged with the main Netgear router and the server is wired into the Airport router via Ethernet with the Pi downstairs running over a wi-fi connection. I'm back on my dedicated Roon bridge installation so all audio is coming over RAAT and it's nothing short of a transformation. There's no exaggeration when I say that it's gone from sounding totally flat and uninteresting, to pretty breathtaking, and the only thing that has really changed is that I've turned off DHCP and NAT routing in the Airport router and switched on bridging so that the Netgear is taking care of all of the network transport stuff. I'm quite amazed how that's made such a difference to RAAT but didn't really affect Shairport. I guess that just goes to show how it very much depends on which of the network transport layers your application sits on top of.

What a difference! That's the singular biggest difference I have ever heard in digital audio. Forget different DACs and power supplies. This is a transformation and I'd recommend anyone running Roon to try something similar...

Of course, it can't stop there now. I'd like to try and eliminate the second router entirely as outlined in the Computer Audiophile post above, but for this my server needs another Ethernet port as it's not possible to bridge wireless with Ethernet, so there's a PCI Ethernet card on order to slot into the server, then I'll see if that brings any further improvements. I'm not expecting another jump like this though for certain.. Wow!

[struth]

over my head lol

[lovejoy]

over my head lol

Well it's turned the whole idea about audio data over a network being packet data and having no affect on what comes out the other side completely on its head for me. It's come as something of a massive revelation.

From what I can gather at the moment, I've taken my audio streams which were going through a router that was already dealing with all of the internet traffic, providing a firewall, routes between all of the other devices on my network, providing them with IP addresses and gateways into the outside world and put them onto a separate router that is doing nothing more than sending data packets from the server to the Pi and taking all of its instructions from the main router, so it's doing a LOT less work.
The ultimate connection has to be a direct 1:1 link just between the server and the playback device with nothing (not even a switch or a router) in between. So having a PC with two Ethernet ports gives you this - One port connects to your main router so you can access it and control your apps and choose your music as usual, but once you've chosen your music, that gets sent over the other Ethernet connection which is a dedicated 1:1 link with nothing else in the way...

[struth]

Better. Ta But I couldn't do it alas
Need to get Gazjam onto this

[lovejoy]

Bit of an update. Rooting through my work laptop bag during the week I came across a USB3 to Ethernet adapter and wondered whether if I plugged that into my server, it would recognise it. Only one way to find out and sure enough it did, so I thought I'd set that up as the control interface and plug that into the main router, then use the server's motherboard Ethernet port for a direct connection to the Pi. I then configured this direct connection as a bridged connection to the other port so then not only could the Pi see the server, but the internet as well via the server.
Fair to say this setup is stunning. Another good step up from the separate router. I guess this must be the simplest of connections between server and Pi with the least traffic and interference from an external router and it shows. With the Pi and Piano/KALI combination connected at the other end and running in Dual Mono mode from the DAC board, the sound reminds me of the first time I heard MQA on a very expensive system. No sonic signature, just incredibly revealing and accurate sounding, giving you the ability to look deep into a recording, but not in a ruthless warts and all kind of way. Just making the very best of everything. Even 6Music over the internet is sounding excellent and that's 128kbps MP3. Hi-res material is just incredible. I have a few DSD files and although the Piano DAC cannot play DSD natively, it's getting converted to 32-bit/192KHz on the fly and it's simply breathtaking in how natural it sounds.

Just a couple of finishing touches now... I'm wondering if I can get away with a pair of homeplug Ethernet over mains adapters going from the server to the Pi. I suspect maybe not, but it'll save a bit of hole drilling if it does work as at the moment there's an Ethernet cable running down the stairs into the living room which needs to be tidied away. It'll have to run around the outside of the house if it is to stay permanently. I'd also like to try and get 384KHz playback working from the Piano DAC. Not because i have any 384KHz music, but because upsampling to that rate means the internal filters of the DAC chip are bypassed which would be interesting to hear. I apparently have the kernel in the Pi which supports 384KHz and Roon says it's playing it, but I'm not getting any sound from it currently... I'm not going to lose any sleep over getting this working though as in the space of a couple of weeks the Pi has gone from being a background music device to being the best sounding source by quite a margin.

[lovejoy]

Just a quick updated on using the Homeplug devices. I bought a couple of the TP-Link units that I'd heard good things about to save drilling holes outside to run Ethernet cable, then ran the dedicated Ethernet from the server into one Homeplug, then out of the other and into the Pi.
Everything seemed well at first. All still sounding great. Then I noticed that the spaces between tracks had this 'tick tick tick' noise through the speakers which obviously pointed me towards the Homeplugs pumping noise into the system. Well I was on the verge of giving up on that idea and going Ethernet, but then it struck me that the noise was only present between tracks and having played tracks with silence in them, there was no noise, so I thought that had to be something else - Maybe power supply noise coming back from the Pi as it fills its buffer with audio data between songs perhaps...
So then I remembered that the KALI board has a jumper that when removed allows you to power the KALI and Piano DAC separately to to the Pi, so leaving my linear supply on the KALI/DAC and removing the jumper, I then powered the Pi separately with the iFi supply I had lying around. Hey presto - No more noise. Now I'm perfectly happy with the Homeplug devices and an extra PSU is still preferable to some serious hole drilling and cable routing.
Now onto tweaking with clock speeds and voltages in the Pi ;-).

[struth]

thats good your sorted.... Ive got a set of tp link plugs and use them mostly for my smart devices. they work well with other applications tho too.

[Mr H]

Hi, I’ve been reading the previous posts with interest.

I use Devolo homeplugs around the house to put all the devices on the network so have a few! They actually do a twin port on a single socket model, so I’ve put the streamer and the NAS side-by-side sharing the plug, not quite a bridge but pretty close. The sound was generally better and more alive and very easy to do.