I have said this before but it has been ignored. I have paired 4 roku wireless speakers to my smart soundbar and it worked great. I disabled the front 2 speakers by unplugging the power cord. Checked the settings from my roku TV and it had a front and rear speaker disabled. It looks like the paring didn't work eventhough the configuration was correct during setup.
I tried paring again after resetting all speakers and not using the front speakers. This improved the rear speakers volume with broadcast suround sound. In fact I had to turn the volume down, because it was louder than the soundbar volume. I think this the problem is with the 2 front wirless speakers are not paring correctly with the smart soundbar. This is the way I'm using the speakers now. It makes the 2 wirless speakers a waste of money until the problem is resolved.