From the FF800, you cannot plug a cable into "the air" (Bluetooth).

You could load the Bluetooth driver into the DAW, but as the DAW (like any other audio application) can only load one audio driver at a time, you would lose the connectivity to the FF800.

This might be possible using ASIO4ALL because it adds a driver layer over any other audio driver (be it ASIO or WDM or whatnot) and communicates to the application using ASIO. But I can't recommend this to you. This leads to an unsupported setup and is against the principle of ASIO drivers having direct access to the audio hardware (FF800) with highest stability and least latency in mind.

Another point is, if you send audio from FF800 to the bluetooth device then the two different devices would need to be clock synchronized. But this is not possible. You would need a digital connection between FF800 and the Bluetooth device (or word clock).

Even if you sacrifice to have a supported setup etc bla and would use ASIO4ALL. I doubt that this leads to stable audio without any issues.

You can try to install audio. For professional work simply load the RME ASIO driver. For all these workarounds load the ASIO4ALL driver. You can control it in your DAW, which driver you want to choose.

Or simply use the Bluetooth driver if it is the only purpose to play music from the DAW directly to Bluetooth.

@Miscreant:

May I ask for what use case you need the connection between FF800 and BT speaker?
Is it really needed to work with both in parallel, FF800 and your active Monitors plus Bluetooth in addition?
What purpose has a Bluetooth speaker in a recording setup?

From gut feeling, it sounds a little bit as if you want to combine things that do not belong together.
Maybe there are better solutions for what you would like to achieve.

Bluetooth, AFAIR, also does not provide lossless audio and Bluetooth speakers are at best consumer devices but have nothing to do with anything like "studio quality". So why this combination?

Thanks for taking the time to reply.

The use case is 'radical' A/B'ing when mixing. So many people today listen to music via tiny portable bluetooth speakers. A lot of them are also mono.

I'd like to be able to toggle between my actual studio monitors and this B speaker without having to print out a copy of my track and then play it through, say, VLC player and select my output via Windows' native sound card.