Is Roon app Device Volume required for Roon Readiness?

I am sure someone will be along to clarify it all.

Hi @scolley,

To answer your original question directly, Roon Ready functionality only extends to the networked streaming feature of the device.

If a device supports USB volume control (UAC 2 volume and/or USB HID volume), Roon will be able to control it by utilizing the OS’ audio device and HID drivers.

I took the time to write up a generalized overview of RAAT and how it relates to Local/USB playback versus Roon Ready devices. I hope it helps clear up some things:

RAAT is a protocol for getting lossless audio & related functions from point A to B over a network connection—with point A being the Roon Core audio engine and B being the endpoint device. The endpoint device runs a process that we’ll call RAAT-App. The RAAT-App takes the incoming stream from the Roon Core and forwards it to the desired audio device using the OS’ audio driver.

Roon Core --network–> RAAT-App --audio driver–> audio device

When the Roon Core is playing to a device running RAAT-App on the network, it sends the data over the LAN.

When the Roon Core itself has audio outputs it starts up RAAT-App in a separate process named “RAATServer”. The Roon Core then sends the data through the “localhost” loopback network interface ( to the RAAT-App process.

RAAT-App knows how to accept RAAT audio streams, but it doesn’t know intrinsically how to do much else. It does not know how to output this data to an audio device. It does not know to forward volume commands.

RAAT-App relies on customizable plugins to interface with the OS’ drivers for audio output and other functionality.

The “RAATServer” process on Windows/Mac/Linux is simply our name for “RAAT-App” that includes plugins for WASAPI + ASIO on Windows, CoreAudio on macOS, and ALSA on Linux to enable playback to local audio devices. RAATServer also includes support for UAC 2 + USB HID volume controls on the aforementioned platforms.

The “RAAT-App” process running on a Roon Ready device includes plugins that are customized by the device manufacturer to optimally interface with the device and best leverage its capabilities. Roon Ready devices can include additional customized plugins to handle things like metadata, album artwork, and transport/playback controls.



Thank you John, that is the clarification that I was looking for. I would like to point out that - unless my memory is incorrect - that is a change to the original state of affairs. Or am I mistaken…

When Roon was first released, there were few things on the market that could even get to digital music over a network except a PC or Mac. There were exceptions (which I used), but that was generally the case. As such, almost all DACs had USB input to them, to play music from Roon on a PC or Mac. And were those DACs originally not designated as “Roon Ready”?

Or has the designation always applied only to network attached devices, and I just missed that distinction?

Thanks again.

HI @scolley,

Roon Ready has always exclusively referred to the networked audio feature.


Wow. I just missed that distinction. So the original Roon Ready devices were ONLY network devices. Interesting.

Thank you.

Hi Steve,

If you remember, Roon did not use RAAT when it was initially released, is was UDP, I believe, but, might not be. RAAT was added in … 1.2?..(scrambles to check)…aha my memory is still doing okay! :smiley: See below:

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You sure Dan? UDP is just a network layer transport like TCP it’s not a streaming protocol. They switched it from UDP to use TCP for more stability.

LOL, well, I did use the quibble words, “I believe”. You are right about dropping UDP in the switch to TCP. It may be that the pre-RAAT protocol was never mentioned? Now I will have to do some research. :smiley:

It does say they moved all aspects of streaming to use RAAT at that point though so yeah no idea what they used before. It does say Roon Ready was already using RAAT though.

I do remember something like that, though details are fuzzy. Though I know that UDP was in the mix somewhere. I recall grumbling about it.Thank you Dan.

And I also find the statement above fairly interesting. From that statement, when RAAT came out in v1.2, there were ALREADY Roon Ready devices. John stated above that any such devices were all networked devices, and always have been.

As I recall the term “Roon Tested” came out a good while after “Roon Ready” had been in place for a while. So prior to us having Roon Tested, what were all those approved-by-Roon USB DACs called if they weren’t Roon Ready? I’m asking - of course - because if I were asked, I’d say they were called Roon Ready. But that memory - possibly incorrect - contradicts what @john has said.

They more than likely had no definition at all as ir wasn’t necessary. No usb device has to be tested to work in Roon. Plenty dacs, AirPlay and Chromecast that are not Roon tested and work the same. I am finding hard to work out why you think they where Roon Ready when their is no documented evidence and John has already confirmed it’s for networked devices only. It even talks about In that article that usb and Roon bridge etc now use RAAT like Roon Ready devices not that they are Roon Ready devices.

As I recall the term “Roon Tested” came out a good while after “Roon Ready” had been in place for a while. So prior to us having Roon Tested, what were all those approved-by-Roon USB DACs called if they weren’t Roon Ready? I’m asking - of course - because if I were asked, I’d say they were called Roon Ready. But that memory - possibly incorrect - contradicts what @john has said.

To the best of my knowledge, Roon has never referred to USB audio devices as “Roon Ready”. I can say this with certainty since I joined in early 2018.

To the best of my search capabilities, the first mention of RAAT and Roon Ready came in October of 2015:

I believe that the “RoonSpeakers” software app became what we know as “Roon Bridge” today.

Yep, it was originally RoonSpeakers; thanks for the memory jog.

Thanks John for the clarification. So what were devices tested by Roon called at that time called? I ask because I know Roon kept a list AND even though any USB should theoretically work, all did not initially, and testing was done on USB devices to ensure they worked.

So unless my memory of such is completely wrong, what did we call those tested USB devices?


@john thanks for the detailed info and the trip down memory lane…great thread!!! One for the FAQ

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Then this Roon Ready device is behaving in a compliant manner for this aspect.

As explained by multiple posts above, Roon Ready = RAAT over network.

The limitation you found with USB does not affect Roon Ready (network).

If the device supports volume control with its native network playback, then Roon Ready requires it to support volume control over RAAT over network. This is known as feature parity requirement of Roon Ready.

If only if the device supports RAAT over network. USB is irrelevant.


In a more complex configuration, you may have a network RAAT device that outputs USB (e.g. Pi or another computer doing a Roon Bridge), then USB input to the DAC.

In this case, the USB DAC is not functioning as a Roon Ready device.

Since you’ve got Roon Ready over network, why would you use USB when playing Roon?

Roon Ready only concerns RAAT over network.

USB input is irrelevant.

To my knowledge, Roon Tested (not Roon Ready) can cover inputs like USB, SPDIF, AirPlay, Chromecast, HDMI, or certain Roon blessed proprietary network protocols where RAAT cannot be done.

On the subject of UDP vs TCP:

Prior to June 2017 RAAT was based on UDP. Since Build 234 Roon redesigned RAAT to use TCP. See


Because my DAC supports higher resolution files over USB, vs. Ethernet or any other input.

That answers the state of affairs now, as has been previously posted here. I’d like to know what all the USB DAC’s, tested by Roon, were called initially. It may well have been Roon Ready. I know John says “No”, but he also indicated that he’s going by memory and he’s only been with Roon since 2018. I’m curious as to what those devices were called in 2015.

Maybe you can use the Wayback Machine to look up product webpages from back then?

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So never Roon Ready for USB, I hope this matter is now put to bed.