I have been very happy with my Fire TV Sticks. Recently, I upgraded all my Fire TV Sticks to 4K version. Now, I am having problems.
I do not have any problem with the the 4K Fire TV Stick connecting directly to my TVs or AV receivers. Everything works just fine!
However, in one of my setups, I have a Klipsch RSB-11 4K Video Passthrough Soundbar. I have been using it with the "standard" version Fire TV Stick and a Samsung 4K bluray player without any audio or video issue. The Klipsch RSB-11 does take 4K video signals.
Replacing the "standard" version Fire TV Stick with a new 4K Fire TV Stick, the audio sounds ok, but the screen keeps flickering on and off. It flickers once every second. tried to change the HDMI cable with higher speed HDMI 2.0 and 2.1 cables. They do not solve the screen flickering issue.
What I have done so far:
1. Using at least two different 4K Fire TV Stick to the same Klipsch RSB-11 Soundbar
2. Updated the Klipsch RSB-11 Soundbar firmware to the latest version
3. Using higher speed HDMI 2.0 (4K) and 2.1 (8K) cables
4. Try to use different USB Adapters (connect directly to different wall outlets)
5. Using different Klipsch RSB-11 HDMI input AND different TV HDMI inputs
6. Using the same Klipsch soundbar and 4K Fire TV Stick with different TVs (Samsung 7000 series 55" HDTV and TCL 65R17 65" TV)
For now, I connect the 4K Fire TV Stick to one of the TV HDMI inputs, and optical fiber (digital) connect the TV to the Klipsch KSB-11 soundbar. It works, but the sound quality is not as good as connecting the 4K Fire TV Stick directly to the soundbar.