ARC bit-perfect in android phone!

Excellent move in the right direction.
Now we just need bit lossless playback without an external dac!


The process for attaching / detaching the DAC, managing the lifecycle of the USB driver, surfacing the correct info in the UI, integrating OS level volume controls, etc is totally different for the two apps since they do playback quite differently. I would say that these integration aspects took up 80% of the calendar for this project, and the USB driver development was the other 20%, so we are talking about a near doubling of effort to get both apps working.

Roon Remote only works at home. ARC works at home and on the go. The only significant gap is DSP, and we’ll close that with ARC as soon as we can, so it made sense for us to do this in ARC and let the Roon team focus on interesting stuff for Roon, instead of duplicating similar functionality that is already possible in ARC.


There are multiple warnings about this from AK - on the HC2 box, in the quick start guide included with the HC2, in the product manual downloadable from the AK website, multiple places on the AK website including the product pages for the HC2 and on most of the dealer pages where it is being sold. Happens by default when connecting some USB DACs to a computer or phone. From AK’s product page - Make sure check the volume on your connected player device before using headphones or earphones. Some devices may automatically set the output level to maximum volume when the cable is connected. Listening to headphones or earphones at maximum volume may damage your hearing. Please verify the volume level before each use.

I believe there are lots of DAP users out here that would appreciate some love towards bitperfect output on Android without an external DAC. Might sell a few subscriptions as well…


Yes, this is planned. This is a multifaceted problem, however. It’s not just about bit-perfect output–many DAPs have flash storage that is not fast enough to run ARC with acceptable performance, and others run very old versions of Android. So it’s likely that whatever result we are able to deliver here will only work well on a subset of products, which is always a bit disappointing for people.

Nonetheless, this is in our plans. DAPs will get faster over time, and they will likely remain popular.


3 posts were split to a new topic: ARC: weak connection

On Questyle M15 dongle, usb Android, no Mqa

Max volume using Android phone into Focal Bathys inbuilt DAC via usb.


Is DSD native possible on IOS?

No. Apple does not provide the needed access to the device. Without major changes from them (unlikely), it will never happen for any product.

I get the same error with ifi go blu and S22 Ultra

Cheers, yeah I thought there was something with Bluetooth codecs but my phone uses Samsungs Scalable Codec which I was led to believe gave Hi Res above 48k when using my Samsung buds.
Anyway I dug out a pair of wired earphones and hooked up to my Mojo 2 DAC and still only get 48k sample rate with Arc when playing tracks of 96K - the light on the Mojo 2 is orange which is for 48k. I have selected the setting Original Format. However play the same tracks via Qobuz and I dont get downsampled to 48k, the light on the Mojo 2 stays at blue for 96k. Am I missing an update for Arc? I am running the latest version of Roon.

It’s possible you are missing the update. Your phone should prompt you to use the USB device with ARC, then ARC takes over control of the DAC. You should see “USB” under “Output” in Signal path.


I think you are assuming that I did not check the level and reduce it before listening. the actual problem I am encountering is, the output is at max no matter what you set the volume at.

how do you further lower a volume which i already reduced to zero, but the sound that is coming out of the iems from the attached dongle is at 100?

Same highest volume while connected via Questyle M15 dac, which has no hw volume keys.
RoonArc 1.0 (94)
Latest early access Roon components’ versions.
S22 ultra android phone.

Note: the new Lossless USB feature, when it worked ok was really sublime.

I can’t get bit perfect to an Android Digital audio player. Any way to do that?

2 posts were split to a new topic: ARC USB Issues on Android (Signal Path)

Sorry, you are correct. I just tried with my HC2 and Samsung S21+ with Arc and experienced the same thing. Set at max and showing 0 volume with no way to turn down the volume. I assume since the HC2 is Roon certified, Roon has the HC2 on hand to test.

For the folks with FiiO KA3(I guess this works for other fiio dongles), here is a workaround how not to shoot the driver trough your eardrums. Go to the play store and download fiio control, next open it and set the max volume from there - default is 120, I set mine to 95. This settings are saved in the amp controller and they cannot be overwritten otherwise. You may also want to set gain from high to low. That’s it. I’ve reinstalled arc as well. So here comes the interesting part. I cannot reproduce the issues now. Volume control is functioning properly also the poping noise from the phone speaker when changing the bit rate of the USB DAC is gone.

Correction! After playing music via arc for 30-40 mins, closing and opening the app and connecting and disconnecting the DAC both issues resurfaced. Reconnecting DAC it sets playback volume to max(ignoring android volume slider position, this is happening only once on the first connect of the DAC to the phone), which is crazy, at least now it’s not so loud because I restricted what the controller inside the device is doing with the amp, and the second one is there as well. Popping noise via phone speaker on each track change. How I can provide more info or data so this get troubleshooted from dev or reproduced by qa? Btw I will try to reproduce tomorrow with another android phone to see what happens. Cheers

ps no issues with UAPP which I am using as well

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Interesting there is no such issues with FIIO KA2