Thank you for the report. We’ll keep your topic regarding the Galaxy phone separate rather than merge these threads for now, as the team is tracking this issue independently by operating system.
iOS reports we will begin to merge into this thread, as we have several reports with iPhone 11 Pro and iPhone 14 Pro Max.
At this time, the team is investigating the issue internally to try pin down triggering conditions. We’re not assuming it’s a result of normal or even extreme operating conditions on ARC or the phone. Transcoding won’t cause a hot phone in normal conditions, even with high-quality file types; neither should connectivity conditions.
We’re particularly interested in reports with downloaded, offline mode, and ARC playback using connected endpoints (like USB DACs).
Thank you again for your diligence and for the precision of your feedback.
Having investigated diagnostics, we’re seeing strong evidence that the size of the library is affecting Roon ARC’s performance. A library of 300k+ tracks, with 50% of them being high-quality DSD files, is unfortunately on the sunset end of the bell curve for database size that will function with any mobile sync setup.
Simply put, due to the size and file quality breakdown of your library, your Roon database may be too big to use reliably with ARC. In order to support operation with poor or limited connectivity, Roon needs to synchronize information about your music library onto your mobile device. While the data synchronized is much more compact than what is stored in the Roon Core, libraries above a certain size will naturally be too big for a mobile device.
Aside from limitations in device performance, there are also restrictions on resource usage imposed by Apple and Google which make this scale of data transfer, synchronization, and storage impractical within a mobile app.
There’s no hard barrier, but the team finds a natural limitation starts to assert itself in the range of 300-600k tracks. Of course, this depends hugely on the phone and the file qualities of the tracks. 400k low-quality files might still work; 600k large DSD files very likely won’t sync at all.
Keep in mind, however, that this might be fully independent of your report of a hot phone during downloading. There is memory pressure evident in logs during downloading, but there’s no direct evidence it’s responsible for the heat. It may be you’re encountering memory pressure in addition to the issue the team is investigating above, so we are by no means dismissing your useful insight or discontinuing further deep investigation into your reports.