- It's definitely no. 2.
- It's not no. 3 in that the Roon app is not a device, it's an app.

I don't know what the difference is between no. 1 and no. 2. Do you mean using the PC/Mac's sound card/system output? If so Roon can do that as well, if you want.

Roon can stream to at least:

System output (this cannot be bit perfect, it goes via the OS mixer)
Internal Speakers (Built in Output)
Headphones (Built in Output)
USB devices like Explorer1/2 etc.
Meridian endpoints (MS200, MS600, ID40, ID41, MC200, MC600, C15)
Apple Airport compatible devices (including Apple TV, for example)


Ex-moderator
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