Been doing some more testing today, and while Netflix is nowhere near as bad as Amazon, the audio on Netflix isn't great either. As with Amazon, dialogue has a sort of hissing sound in the background. I'm still on the 7.6.0 build 4125 firmware, last updated on May 5.
I'm experiencing very poor audio quality with Amazon on my streaming stick, dialogue in particular is very difficult to understand. Amazon used to be fine (not used it for a few weeks so not sure exactly when it went wrong) and Netflix is currently fine.
Anyone else got this issue?