I own the SKY10 sound bar and it has volume control for the rear speakers. When I first hooked up the speakers they did not work because I had not adjusted the rear volume control setting on the Sound bar menu. The LG sound bar remote has a button that looks like an EQ. If you press this button it lets you set up the volume on stuff like Bass woofer , center speaker , The ATMOS upward firing speakers & the rear speakers on the SKY10 sound bar.
I hope this helps.