Our Roku Ultra 4661 began having an audio problem about six months ago. Our AV system gets turned off every night, but after roughly a week of off & on the audio from the Roku has a "burbly" sound - like the is coming out of bubbling water. Making it do a full reboot via the menus restores the sound quality. The audio has the same issue on all channels, ranging from our Plex server to Netflix. The Roku is connected to our home network via wired Gigabit Ethernet, not WiFi. Its audio output is via the HDMI connection into our Yamaha RX-V679BL.