The volume problem with Roku TVs is a nightmare. I don't have yet a solution, but I'm starting this thread because I feel I am at least narrowing down the problem. The volume gets soft during loud scenes. There is no volume levelling setting, and this occurs even if I have audio coming through a soundbar on ARC.
I’ve at least narrowed this down. For Roku, if you’re listening, here’s the symptom: you set the volume to a respectable level and everything is fine if the volume of the scene is normal or low (a conversation, a dinner, etc). But as it turns into an action scene full of loud noises and explosions, the volume drastically drops and you can’t hear any dialogue. You have to push the volume to near 100 to even hear anything and it’s still no good.
What’s happening here is there is some auto-leveling of audio that’s happening on the TV side that’s affecting the TV speaker and any soundbar connected to it. I don’t know if it’s a Roku problem or a TCL problem, but I bet someone in manufacturing knew they were putting in **bleep** speakers from the get-go, and to prevent a high incidence of RMAs, they programmed the firmware that any high audio level is compressed to prevent damage to the speakers.
Understandable, but the only problem is that code in the firmware is also applying at any soundbar connected via ARC.
Either Roku or TCL need to work together to get this fixed.