Why I don't understand ARC


where is my error?

I configured the last version of Roon and ARC on my Iphone.
I downloaded some albums. I can see the downloaded album with the symbol indicating that the album has been downloaded on my Iphone.
I set “Airplan mode” to be sure that no connection is active.
I choose the download album in ARC … But I cannot play id because ARC told me that I am in offline mode … BUT, it is not this the reason why ARC has been development?
Where is my Error?



Hi Claudio
I don’t understand that either, and it’s not the case with me:

Plays flawlessly.
Surely there will be enough storage space on your phone and your software is up to date?
You might want to try rebooting your phone.
If that doesn’t help either, you could try uninstalling and reinstalling ARC.
I hope this resolves the issue.

Welcome to the community, @Claudio_Ferroni.

Have you set up Roon core on a PC or Mac? Roon Remote and Roon ARC are control apps that connect to your core.

Please take a look at the following to understand how Roon works.

Works as advertised for me.

What do you see in ARC when you select My Library > Downloads to go to the Downloads screen?

Ciao! I saw the list of the albums I downloaded. In this moment it’s works. But sometime, after switching on the airplane mode or I am disconnected from my network, I can listen just some of the albums I downloaded.

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Thanks for the answer: My roon server (last build 1133) is up and running on an ASUSTOR NAS.

Have you tried engaging the new off-line mode switch in settings?


Strange indeed. :thinking:

You might consider posting in the Support section.

Its because you’re using Airplane Mode. You don’t need to if you have the Arc app in offline mode, and it won’t work of ARC can’t connect to your Roon server anyway, even though you are not streaming the music, it still needs to connect to the server. Just switch Airplane mode off

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ARC is expected to work for some time if completely offline. Obviously only with downloaded files

Interesting this “Sometime”, that’s mean that if i remain disconnected with roon server for a long time (days, weeks, month … is there a limit?) I cannot listen anymore the download music?

Now its working using the “offline” switch. BUT, reading your reply it’s mean that is I’m flying in airplane, because i must switch to Airplane mode I should not set the offline switch in off? I suppose that I have to set offline mode switch on anytime I cannot connect to my roon server and … in case I’m flying … I set the airplane mode too.

After discovered this swicth, yes :smiley:

Of course the airplane mode should work, it’s a bug if ARC does not work with downloaded files just because airplane mode is enabled.

The offline switch in ARC mainly informs ARC that you know that your Core is not available. E g. ARC then does not have to tell you all the time that “core is unreachable”.

Regarding the “some time”: The ARC app does need an occasional license check. Roon is using 3rd-party metadata. Even though you own your files, you (and Roon) don’t own that metadata. Though I don’t think this needs a connection to the Core or much data, it’s just a quick check with Roon’s servers for your license, I think


What I don’t understand is the question itself! While I do see the benefit of being able to use Roon, let’s say, on a plane, the real benefit I suppose - and presumably the raison d’etre of ARC — is having true streaming remote access, WITHOUT having to download files locally to your phone.
Is that not the purpose??
Also I will make 2 points:

  1. that I do not find ARC to be reliable- I can often connect directly with LTE to Tidal (ie via Tidal’s app) but ARC complains of poor connection and does not connect
  2. I have not seen any write up from Roon on just how it is making mobile work - is it throttling and/or buffering and/or lowering quality and if so down to what level?

I would say that the benefit is mostly mobile access to one’s own files (that may not be available on streaming), the additional metadata provided by Roon and/or edited by the user, and integration with the playlists, tags, etc., one has in Roon. And having the option to do this by streaming and with downloads to the phone (as streaming is not helpful if you don’t have a data connection).

Regarding the reliability differences you are seeing between ARC and Tidal, ensure that you are using comparable quality settings in both apps.

The currently best available description is probably this one

I don’t think there is anything more technical publicly available

You really can’t compare Tidal app and ARC. There paths to device are very very different, even though they are giving a similar service.

One is a direct connection to Tidal one is direct connection to your core at home very different paths and has 3 variables to contend with, the reliability of you internal network connection to Roon core and router, the reliability of your home internet connection and the reliability of your cellular connection. Tidal uses local CDN to distribute data to your phone so the cellular services dns will connect you via the best and nearest connection. Your Roon core is fixed and can only be accessed via one route so is going to have some variable connecting from time to time.

As for What Roon does to the streams that’s all laid out in their FAQ on Arc. It has several options as to how it operates dependant on the connection you are using.

I think I’ve uncovered something interesting for offline mode. If you downloaded an entire album, you may need to have ARC 1.0 (build 59) in online mode and view the album at least once to allow it to download ‘Selected discography’, ‘Recommended Albums’, etc. Once that is done, I can immediately put ARC back into offline mode and ARC now allows me to play the downloaded album offline.

For those interested, here are more details since I was in a non-ideal configuration for a few days.

I originally downloaded all of my albums one by one in Arc Build 49. (I tagged all my local albums as “Local”, so that made finding them in Arc easier.)

When the latest Roon 2.0 (build 1133) and Arc 1.0 (build 59) came out, I was on vacation. At that point Arc on my phone automatically updated, but my core did not since I have it set to not auto update. In this configuration, my downloads would not play in Arc even if I put Arc into offline mode and I figured it was a version mismatch causing the issue.

However, now that I’m home and everything is upgraded and rebooted, I noticed that some downloaded albums will play in offline mode while others will not. I can’t even hit the play button for the album and the following message appears “ARC is offline - Disable offline mode in settings or listen to your downloads”. The album I’m trying to listen to shows the download checkmark, so there’s a conflict here. Using the work around I provided above fixes this.

On a side note, if I let Arc download too much at one time, my phone heats up and download speeds are greatly throttled. Spacing the downloads out and keeping Arc in the foreground with the display always on seems to cause fewer corruption issues later, but I need to test that out more. (Android 12)

No need of arc
Qobuz or Tidal are way ahead