Roon ARC: iPhone resampling at 48KHZ

I am trying ARC on the my iPhone XR and noticed that everything is re-sampled to 48khz.
This means that lossless is available only for recordings which were originally published at 48khz, while anything else gets a “high quality” tag.
Is this normal? I guess it is related to the iPhone DAC but I thought I checked to make sure this is the case

Use an attached DAC for higher resolution with your iPhone.

Thanks! I will give it a try, should have a couple of dongles somewhere…

Yes, that’s normal. ARC checks with your phone to determine which sample rates are supported.

In most situations, iPhones run at a fixed 48kHz sampling rate internally. Roon is determining that and adjusting its output to what your phone supports so that we can use our high quality sample rate converters instead of the one that comes with the iPhone–which is what would be used if we sent 44.1kHz audio to the phone.

This 48kHz situation applies to most mobile devices, bluetooth devices, and small form-factor 3.5mm adapters for lightning and USB-C phones. On mobile devices, we live in a 48kHz world for the most part.

If you plug in a USB DAC that supports more sampling rates natively, ARC will support whatever the DAC supports without conversions, just like Roon Remote always has on iOS.


Will Roon ARC work with Astell and Kern SP 1000?

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There are Android apps like UAP (USB Android Player) that have drivers to bypass the Android Audio stack (and thus avoid the re-sampling). Is this something Roon could possibly implement?

Incidently, I have a Helm audio Bolt USB-C MQA DAC/HPA and neither Roon app seems to detect it. This is on an Xperia 1 III running Android 12. Music seems to be playing, but Roon doesn’t seem to register that there’s a USB device connected. So re-sampling is still happening.

I was just about to ask about that ie players like UAPP and whether roon can do the same.

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So a Dragonfly will work in the same way on ARC as it does on Roon?

Of course. There are lots of DACs that are small and portable with different capability and prices.

No. Roon ARC requires Android 9.0.

Chord Poly?

Thanks for your reply

I currently enjoy Roon ARC on the iPhone with my USB Dac “LOTOO PAW S2”. Works flawlessly. Interestingly, I find the sound quality better than when I use the Roon Remote app and use the iPhone with attached LOTOO as the endpoint. But that may also be my own imagination …

So here we are full circle. Roon made me a lossless snob by making me care if I had a Purple star or not when listening. Now that mobile gives me a Yellow star, I’m thinking to myself, "I don’t want to listen to that crap. :grin:


Set Roon ARC to “Original Format” for both WIFI and cellular and plug in a DAC.

Unfortunately it does not work (at least for me). Roon ARC still up samples to 24/48. It does not recognize the DAC. That’s a pitty.

Did you set the Roon ARC app to “Original Format” for both WIFI and cellular?

Yep. I did. Unfortunately neither ARC nor Roon classic app recognize the USB DAC… so it up samples.

Are you using an iPhone or Android?

Android 12. (Samsung s22 ultra). Maybe that’s why…