Roon Server running on MacBook Pro (13-inch, 2020, Four Thunderbolt 3 ports), 2,3 GHz Quad-Core Intel Core i7, 32 GB 3733 MHz LPDDR4X
Networking Gear & Setup Details
Ubiquity UDM-PRO, AP nano-HD
Connected Audio Devices
Google Chromecast Audio connected with optical cable to Cambridge AXR 100
Number of Tracks in Library
less than 500.
Description of Issue
I’m usingthe Roon App on iOs and I’ve noticed that, multiple times per listening session, there are random intrerrptions while playing. I don’t know whay this is happening and I cannot asociate it with any local network problems, because when playing back from Spotify the intrerruptions do not occur.
So my thinking goes to something between the the RoonServer & the Google Chromecast device as sometimes, the RoonApp does not show the Google Chromecast and a restart of the app or restart of the RoonServer is necessary to pick it up.
These issues do not apper in all listening sessions, but they do occur a couple of times per week.
This sounds like a network issue. Roon’s networking protocol is more demanding on networks than other music or audio services. Audio interruptions and dropouts usually are caused by network congestion.
You don’t mention it, but is your Ubitquiti AP set up with separate 2.4 and 5 GHz SSIDs, or combined? And does your Chromecast Audio have support for both bands or only 2.4 GHz? I separate my bands and force IOT and other low-bandwidth or legacy devices to use the 2.4 band, and higher-bandwidth, more demanding devices and services to the 5 GHz band (actually I have a tri-band router and separate even further devices on the two 5 GHz bands). This may help if you can use the Chromecast on the 5 GHz band which should help mitigate congestion.
One other area to check. Do the interruptions occur if you are just playing the Roon Core on the Mac locally? This would help to isolate if this is a Core issue or a potential network issue.
I have several APs through the house, and they broadcast 2.4 & 5 Ghz networks. The Chromecast Audio is connected to a 2.4GHz network that it’s broadcasted by two APs (out of 5). However the issue does not occur at all when using Spotify for playback - not a single time. So my thoughts went to how the network stack is built inside the RoonServer rather than being a network issue.
Thank you and a follow-on question. Is the Chromecast Audio able to connect exclusively to the 5GHz band? 2.4 does not have the channel capacity and is a very crowded band in general (Blietooth, microwave ovens, and due to its longer wavelength, noise from other devices in the neighborhood).
Roon’s RAAT protocol is very sensitive to timing synchronization and in general to network link capacity. While I’m not a user of Spotify, these streaming services tend to have more forgiving network interfaces and usually allow some sort of network caching/buffering that I don’t believe Roon implements.
Also, the streams are going to the RoonCore, processed to PCM (which is a bigger file), and then sent out to the endpoint in near real-time playback. This is why it is important, imho, to not run the Core machine on WiFi.
Thank you for your answer & details on the RAAT protocol.
The Google Chromecast Audio should be able to connect to 5GHz. I’ll try to do that and see how it behaves.
Caching/buffering & retry mechanisms I had in mind as well when thinking about Roon’s network stack.