Hi

You would have to unpair them from the ARC and then add them back again once you had finished using them just for music. Plus you would have to stereo pair them each time for just music too.

It would be a bit of hassle I think and yes, you would also have to re-do trueplay each time too. 

It’s important to understand what is at work here.  When adding surrounds, the radios are reconfigured to a one-way dedicated 5 GHz connection from the soundbar to the surrounds.  This requires a series of handshakes to get right, which is why adding surrounds takes a bit of time.  The reverse happens when the surrounds are removed.  So therefore, an “easily” done toggle between the two is not possible.  They could place a hot button that does the add surrounds/remove surrounds at the touch of the button, but that is not going to speed up the actual process, and doesn’t save much from the system menu commands we have today.

An alternative would be allowing one to mute the front device and just play out of the surrounds, which would appear to be easier to do, but I defer to the actual engineers on the practicality of the idea, especially with regards to spatial audio.   I’m sure switching from sending just surround info to sending a full Atmos audio stream through the surrounds from the soundbar isn’t trivial, and given hardware limitations of the decoder and the way it is wired to the soundbar, may not even be possible.  Maybe in the Arc 2, perhaps ?

The only ‘easy’ way to be able to have the Home theatre set up sometimes, and music set up other times is to spend more money, and get a separate stereo pair just for music 

This is what I and many others have in their living rooms.