ORBI wireless backhual interfering with Samsung HW-Q90R soundbar and subwoofer

I've purchased The RBK50 system with RBS50 and RBR50

i have HW-Q90R soundbar with latest firmware 

when the router is on by itself -  no problem

when the satellite is on by itself - no problem (but obviously no internet)

once the router connects to satellite - there is interference

The interefernce causes the subwoofer to have crackles and drops (i.e. becomes silent) for a second or so, very often, (Every 5-10 seconds as soon as i turn off either RBR or RBS the crackles go away. 

i've uesd telnet to change the wireless backhaul channel - the only one that works is 50, it fixes it for awhile. Then at some point in time it must jump back, as the crackles recur. I'm not sure what triggers it to recur.  Interesting, when changing to channel 50, i can't the hidden channel reflected on a channel analyzer app on android.

The system is such that 

ORBI router -----------5m --------  soundbar  --------5m----------- ORbi satellite

they're about 5m apart. 

really not sure what else i can do to fix this problem. (no option to hardwire)

seems like i need a way to disable the frequency hopping of wireless backhaul?