Very high data transfer when streaming to Android DAP

Roon Core Machine

NUC i5 10th Gen, HyperX 16GB (2x8GB) 2666MHz CL15 Impact Black, Samsung 1TB M.2 PCIe NVMe 970 EVO Plus, Ubuntu Server 20.04.2 LTS (Focal Fossa), Roon 1.8 (build 898), Wired

Networking Gear & Setup Details

ISP provided 1Gbps Router, WiFi 5GHz running at 500Mbps+

Connected Audio Devices

  • Fiio M11 Pro - Roon 1.8 (build 898), WiFi
  • Mac Book Pro Mid 2015, Roon 1.8 (build 898), WiFi
  • RPi 4B 2GB Ram, HifiBerryOS (release from Oct 2021), WiFi
  • iPhone 13 Pro Max, Roon 1.8 (build 898), WiFi
  • Desktop PC, Win 10 Home, AMD Ryzen 5950X, RTX 3090, 2x16GB Crucial Ballistix DDR4 3600MHz RAM, 2TB Corsair MP600 NVMe SSD, Roon 1.8 (build 898), Wired

Number of Tracks in Library


Description of Issue

Hi there!

At the very beginning, I would like to note that I paid attention when writing b for bit and B for byte. :slight_smile:

I have noticed that Roon Client on my DAP (Fiio M11 Pro) uses a terrible amount of data transfer. When I stream a single uncompressed, ~50MB Flac file, it uses several hundred MB of data transfer. My other Roon clients listed above do not have this issue and use more or less expected data transfer.
I attach screenshots of my Roon Core network monitoring when streaming the same ~41MB, 3:50 long Flac to DAP and Macbook

It looks like Android Client uses around 5x more data transfer. App to measure data transfer on My Fiio confirms this. I used several GB of transfer while streaming a few songs. All my remaining devices use from ~270KiB/s to ~330KiB/s but Fiio uses over 1.1MiB/s.

Any idea why this happens? This is not an issue when streaming via my home LAN, but it is when using poor hotel WiFi. I migrate Roon Core to my Mac then and it causes playback drops on Fiio.

It matters even more when using VPN as hotel WiFis tend to have some data transfer limits. I understand that Roon is not designed for remote use, but technically it is possible and I see no justification for the Android app using that much bandwidth. Especially that it causes issues in hotels even when using no VPN.

I would also appreciate if someone has a Roon Ready DAP (A&K?) and could check data transfer on it as well.

Kind regards,

Please look at the signal path in Roon to see what gets streamed.

1.1MiB/s = 9.23 Mbps = 192kHz/24bit

Does this math reflect what happens in your case?

Note: Android DAPs report their current audio setting to Roon and and Roon then re-samples all audio to that when streaming. Standard for Android is often 48kHz/24bit but as others reported in older threads, when you use other ways to playback audio at higher rates on your DAP, then that higher rate gets subsequently reported and used by Roon.

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It definitely does!

I can set bit depth back to 16bit (that’s what my files are) in advanced device settings but I cannot go back to 44.1kHz with sample rate. Is it a global Android issue that I have no way to fix?

Also, one more thing caught my attention in Signal Path view. When I stream to other devices, my 16bit Flac is converted to 64bit, DSP (volume leveling + crossfade) is performed and the signal is converted back to 32bit. I can set it to 16bit but what’s the point of defaulting to a higher bit depth than the original signal is?

As I wrote, Roon uses what’s reported from your device.

Can you not just use another way of playback, local playback on the DAP of a 44.1kHz/16bit track for example, to change what he reports?
If that does not work, maybe another DAP user can help you out with a method. Seems to me that you already know where to find the DAP threads on the forum. I don’t know of a method in Roon to fix what your DAP reports. So asking for this in the support section might not get you more than the official confirmation that it’s not a Roon problem.

Roon tries to deliver the highest quality possible. If your audio device settings allow for 32 max bits per sample, then that is used. I don’t know if it also has any benefit to it, maybe others can comment on this.

Yeah, I found an old Fiio M11 thread regarding this. There are workarounds advising to play some music using another app and then go back to Roon.


I wonder why this is not available for Fiio:

It could solve the issue. I can set the bit depth to 16bit for Fiio as for any other device but I cannot change sample rate.

You can’t change any sample rate settings for Andorid it’s fixed to what Roon gets back from the OS, which they decided was best for compatibility. In my case its always 44.1/24 on my Hiby DAP.

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Thank you all!

Roon’s Android app has always been a disappointment in that it does not take advantage of the high resolution, SRC bypass capabilities of DAPs.

Vote here for feature suggestion:

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