I’m going to answer your question tailored for a Meridian/Sooloos user that understands that Roon will be a similar product to Sooloos. Correct me if that is not a good assumption.
Right now, we have a software-only offering, and that is what we will ship first. It will run on OSX or Windows. Think of running it on an small Intel NUC or a Mac Mini, and that being your “system core”. Or, you can run it standalone (Core+UI in one) on any laptop or pc you may have lying around.
You will be able to control it from another OSX or Windows or Android tablet. iPad is going to come very soon after. Unlike the Sooloos offerings of the past, the UI you see will be the same, no matter the device you run it on (this will not be true later when we add a custom UI for phone form factors, but that is not going to be available at initial release).
The software supports music on your own built-in or USB/Thunderbolt connected harddrive/SSD, or over the network on a NAS.
The software supports a variety of audio endpoints. The list is not finalized for release yet, but will surely include Meridian, Airplay, Linn’s Openhome/Songcast, and something new called RoonSpeakers. We are working with other hardware manufacturers to include RoonSpeakers support in their hardware. We also have some additional protocols in the works. UPnP/DLNA is not one of them. The support there is horrendous and inconsistent. Maybe soon, I’ll write a blog post about why its so bad.
We also support USB endpoints, via the OS, and via “exclusive” or “direct” mode, which bypasses the OS mixer. This allows a bit perfect stream from our application to the endpoint. We will be certifying many products in this mode. Others will probably work, but when we certify that they work, we are sure no one is messing up anything. Unfortunately, there are a million ways to screw up the audio stream, and many products inadvertently do. Also, as of Android 5.0, there is a possibility to support USB endpoints there too.
We will support all the common file formats at 1x,2x,4x,8x sample rates, and DSD (over PCM), and although we will not provide any DSP filters at first launch, they will come soon after.
The software will require a data subscription (very affordable annual subscription, or a one time lifetime license). The data and experience we provide using this data makes everything else look and feel ancient. We have moved away from artist -> album -> track hierarchy. This exists only as a small portion of our navigation. I wont speak too much about this here, as our blog and the the website will soon be ready with a ton more information about this.
Hope that gives you a bit more information for now… remember, we haven’t launched yet! Things are still in flux!