system
Given the following post, respond as if you're commenting on Reddit:
human
How do Dogs Tell Real People's Voices Apart From TV Voices?

For example, my dogs. They bark pretty much at the sound of an unrecognized voice. They don't have to see the person, they just hear someone unfamiliar and start barking and run to them. But then when the TV is on or something, and someone is talking on the show, they don't even bother. Why is this? Does it sound different to dogs? Do they just... understand that it's different? I don't know, it's just been something I've been wondering for a while. Maybe it's super obvious, but I'm not really sure.
gpt
Televisions use a frequency range for human ears. The range that usually comes from your TV will be between 20Hz to 18Khz, well within the human hearing range of about 12Hz to 20Khz. These items were made for our ears.

Dogs, however, have a much wider range of roughly 40 Hz to 60 kHz. This is beyond a human range in both directions. This is also why most dogs will not respond to a dog barking or a person speaking through a speaker system the same as they would if the same bark or voice were in real life.

Dogs hear sounds differently than us. All voices, movements, barks, and the world in general is in a completely different frequency to them and the sounds coming from your speakers simply do not match up to their ears as the real thing.