Why does sound volume drop when pic quality rises?

[Kermit power]

I've only got one 4K TV channel (BT Sport Ultimate) so I guess they might have just chosen to have the volume level lower than it is on standard HD channels, but I've noticed that in turn, the sound level on any given HD channel will be quieter than its SD sibling.

Does anyone know why this is the case?

[Kermit power]

Having had the same issue on different TVs, different amps, different connections (Optical/HDMI) and watching different channels, I can only assume that for whatever reason, the transmission goes out somehow with a lower volume level, rather than it being anything "wrong" with my equipment.

I don't have the faintest idea why that is, though, so had hoped that there might possibly be someone on here from the broadcasting side of things who could enlighten me.

[Kermit power]

legzr1 said:

JimbobVFR said:

A Dolby or similar sound track will generally have a greater dynamic range which means the difference between the lowest and highest sound levels.

This.

I recently sorted out an Arcam soundbar for elderly parents. It’s a revelation compared to TV speakers but not exactly ‘hifi’ . When watching HD or 4K channels with DD they complained that ‘voices are quiet then it’s too loud with bangs and crashes’..
After failing to explain dynamics and the reasons behind it I selected an option on the Arcam which levels the sound giving almost zero dynamics and they love it.

I give up....

I'm with them on that!

It's great having all that dynamic range when you're watching a film in a soundproofed cinema, but a right pain in the arse if you're trying to watch something without disturbing kids who've gone to bed or pissing off the neighbours!

Fortunately, my amp has a setting which boosts the centre channel where most of the speech is, so I no longer have to choose between all the actors whispering or replacing all my windows after an explosion if the actors are talking normally!