Thanks for sharing Brian. Some interesting things in the pipeline.
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I can honestly say that ARC has already exceeded the low expectations I had for Roon’s high end mobile audio software goals. Just a quick glance through the forums and anyone can see that it’s extremely difficult just getting the base software setup complete with so many different vendors worldwide to have to deal with when it comes to the hardware side of things, and then we get to the network issues…again, worldwide. So to have the ARC software pretty much working as expected is a pretty solid effort to this point. But it needs to be really polished to the point that there is not as many to almost NO issues before the dev team can go on to DSP, the volume issue with USB DACs, bit-perfect playback, etc.
I have tried some of the workarounds on my Android phone and Dragonfly Cobalt to get the volume set without the output gain being sent to the AUX jack in my car at 100%, and they all work to a point. That’s good enough for me for now. My main use of ARC is in my vehicle and there are way too many conditions happening that are totally out of my control that affect the sound quality anyway.
i don’t know whether others are facing the same frustration, but as things stand today:
- If I use the classic Roon app I don’t have bit perfect but I do have the DSP features
- if I use the ARC app then I do have bit perfect playback but no DSP available.
Is there any possibility of ARC incorporating the DSP feature in some future release?
Read above Brian clearly mentions they are working on DSP.
As for bit-perfect support on Android, there are really three use cases:
- USB output (released in November)
- Headphone output on phones
- Headphone outputs on DAPs
Additionally, we have DSP coming as an audio-oriented feature for ARC.
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Does “headphone output” include bluetooth headphones?
Good to see Roon Team understands what work needs to be done for the DAPs! 
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No it already works with BT nothing needs to change here. Headphones out on devices with proper hires dacs, many phones now have better dacs and of course DAPs do.
Just to make sure I understand correctly, with an Android phone or DAP (eg. Sony A306, Fiio M11 etc), ARC is able to perform bit-perfect transmission up to the BT headphones capability?
This is not the case in my experience. When using ARC to play a 96 kHz file, my Android will only send 48 kHz max (after ARC downsampling) to my Sony XM4 headphones that are capable of 96 kHz, so work seems to be required on BT transmission as well.
Which BT codec is your phone using? The XM4 seems to support SBC and LDAC, no AptX. So you will need LDAC support in the phone
BT isn’t bitperfect ever on anything it’s a
Compressed codec transmission system. Arc doesn’t do anything with it it’s up to the device and headset.
Yes I have LDAC support on my phone so I use LDAC protocol on my Sony XM4.
In this case, ARC actually downsamples to 48 kHz when it should be sending 96 kHz that my phone and headphones are both capable of.
I think DAPs don’t have this 48kHz limitation issue, but then ARC doesn’t have bitperfect playback on DAPs either, really frustrating.
Hm yeah right, I tried with AptX and my Sonys and it also converts to 48. Not sure if my phone could do something else though, it’s a Fairphone 4 and I can’t be bothered to find out 
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It should transfer BT at the max rate the device supports for BT it has nothing to do with the devices DAC which the Android/Roons SRC comes into play. Users have it sending 96/24 to the BT side of things which will be transcoded tk LDAC or AptX HD which isn’t in any way lossless. BT is all about the devices Bluetooth setup. aptxhd only goes to 48khz, LDAC can go to 96/24 but non are lossless.
I understand this but I’m not looking for lossless when using LDAC.
Just wishing ARC doesn’t downsample 96 kHz files to 48 kHz on Android phones. I think the confusion can be cleared up by simply seeing the signal path which shows that ARC downsamples and not the phone or BT that downsamples.
It doesn’t if you’re using Bluetooth as this has nothing to do with Androids system limitations as Bluetooth has its own encoding system and DAC is in the receiving Bluetooth device.
Just did a test from m11 plus to my Hiby DAP via LDAC as I don’t have any LDAC headphones. It upsampled my 48/24 album ito 96/24 the max LDAC transmission rate. If it was a 96/24 album it would not have resampled.
Here is a 96k album , hiby on right receiving stream from m11 on left via LDAC. What is evident is ARC doesn’t show its playing via BT even though it is.
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Same 96/24 album to me Sennheiser Momentum 4 it down samples as it only supports 48k
So arc gets what the supports BT device is and sets all audio to it.
Ah that explains my result. For some reason my FP4 does not let me choose LDAC although it is listed in the Developer Options.
@RoonFan Tried on the Samsung tablet which does LDAC and it does 96 just fine:
You can’t avoid resampling with BT either way though as it’s a one fit all codec it has to make all content be the rate it accepts so it’s all moot if it did only downsample to 48khz which I doubt would not be detrimental to BT anyway. Tbh even Roons resampling of non BT to whatever rate the devices DAC reports back to Roon isn’t really noticeable it does however cain the battery more on the device and one of the reasons ARCs such a battery hog.