HELP: Belkin USB-C to HDMI + Charge Adapter won't play audio on my TV

[KES3059A3]

I have this Belkin USB-C to HDMI + Charge Adapter, and when I connect it to my iPhone or MacBook Air (both running the latest "26" OSes), and then use an HDMI cable to connect the other end of the adapter to a TV, the video from my MacBook or iPhone will show up on the TV, but the audio won't play through the TV's speakers (only the iPhone or MacBook speakers).

This problem was present in iOS 18 and macOS 15 as well.

Even more baffling, when my wife plugs in her Samsung Android phone to the adapter, we can play both the video and associated audio through the TV using the same setup.

I'm baffled why audio won't play when using my iPhone or Mac. Does anyone have any ideas?

 

[PaulD-UK]

@KES3059A3 You need an App like Better Display or Monitor Control, or eqMac.
Using one of these (all have free versions) will allow control of an external monitor's volume (and brightness etc for the first two) from the Mac's keyboard.