@rego Roon Ready is not the same as Roon Core. A Roon Ready device is like a Roon RAAT Client, while the Roon Core is like a Roon RAAT Server. The Sigma Streamer is only ever described as Roon Ready.
From the Sigma Streamer manual, page 10:
The Roon playback engine - Roon Core must be installed on a music server like the exaSound Gamma Server or any third-party music server. Roon Core can also be installed on Mac or Windows computer. Your Roon server must be connected to your home network and to the Internet.
For all music streaming, there are three components: the music server, the music client, and the control UI.
The Sigma Streamer is never a "server" as far as I can tell. For any of Roon, HQPlayer, UPnP, or AirPlay. It is only a client. Sigma sells servers separately.
For the four examples listed, the server is:
- Roon Core is the Roon server. It can be installed headless (no UI) on Windows, macOS, Linux, supported NAS operating systems like QNAP and Synology.
- HQPlayer will run a server when installed and running on your computer.
- A UPnP server might be MinimServer running on your computer or NAS or, sometimes an audio device like the Marantz ND8006 that can UPnP serve the CD inserted into it if I remember correctly.
- An AirPlay server is your Mac or iOS device.
For the for examples listed, the control UI is:
- For Roon, that will be the Roon UI app which might be running on the same computer as your Roon Core, but it could be the Roon UI app running on an iOS or Android device.
- HQPlayer is itself also the control.
- A UPnP server could be made use of via an app like BubbleUPnP (not BubbleUPnP Server) or Glider.
- AirPlay is usually controlled by the AirPlay app on the same device as your AirPlay server, but not always. An example of not always is when using the Apple Remote iOS app, where your music might be on your Mac but you use the Remote app on your iPhone to tell your Mac AirPlay server to send music to some other AirPlay client.
Roon has a
handy chart showing these three components of control app, server (Core), and client (audio device) for their software downloads. The chart doesn't show hardware, like the Sigma Streamer, but Roon Ready and Roon Tested essentially fall under the client / audio device column.