I do not understand your comment about 5.1 full sonos setup with 4x Sonos OneSL + PlayBar + Sub?

I assume you mean 2x Sonos OneSL + PlayBar + Sub.

The only way to take out the Playbar from playing with its two surrounds is to unbond it and treat it as a standalone separate ‘Sonos’ room. 
 

If you have stereo paired any of the 4 sonos one SL’s, then you can bond the sub with either pair (or use one of them standalone with the sub). You can choose to group the Sonos rooms to suit your own preference.

I have 4x Sonos OneSL: one in each Top corner of the room + 1 PlayBar+ One sub

it is split in 2 rooms: 

• HomeCinema: PlayBar + 2SL (Surround)+Sub
• Lounge: 2SL ( above the PlayBar)

So in HomeTheatre mode, i activate the 2 rooms (HomeCinema + Lounge)  to have 5.1, but in music mode…. i have an issue with the PlayBar being linked to its surround, i would like to have the 2 SL of the surround+Sub but not the PlayBar,

I understood some speaker could not belong to 2 rooms….

thanks in advance for your help...

Then the only way to play to all four `Sonos One SL speakers (without the Playbar) is to unbond the two surrounds from the Playbar, but it’s a nuisance to do that. 
 

Do you not like the sound when the Playbar surrounds are switched from ‘ambient’ to ‘Full‘ for music audio in the Playbar Room’s surround settings?

I like very much the sound in “Full” mode but the PlayBar is too present in the sound regarding the 4 other play and it is not good to listen to music, it makes a heavy desequilibrium ( and i am a casual user)

I am sure every Sonos user have this issue if they put 4 SL in the corner of their rooms.

As it is software, it should be simple to only mute the PlayBar, the quallity would be raised to fantastic and we could have a real music room

:-(

I’ve just used the volume adjustments in the controller for my surrounds for music to adjust the balance between them and my PLAYBAR. It’s a bit hidden, but if you go to Settings > System > (Room name) > Surround Audio, you’ll find where you can make those adjustments. Note that they’re different for both the video input and streaming music, so you can adjust one setting, and not mess up the other. 

Bruce, it would be fantastic but I can not find this level controleur
I can see the surround adjustment but not the PlayBar.

So near of the goal… thanks for your help

You’re only increasing the volume of the surrounds in relation to the PLAYBAR.  Change the setting to 15% and then test. That’s the best the Sonos software allows, unless you choose to unbond them as surrounds, and set them up as a separate stereo room. 

I’m not a fan of the signal coming from behind my head for music consumption, most often I use a pair of PLAY:5s that flank my PLAYBAR, which also serve as AirPlay 2 target. 

Thanks a lot !!

I will follow your advice, you are right !!