Homo sapiens, the first modern humans, evolved from their early hominid predecessors between 200,000 and 300,000 years ago.
Alexander Graham Bell patented his first electric loudspeaker (capable of reproducing intelligible speech) as part of his telephone in 1876.
There is nothing "natural" about listening to speakers or headphones. Natural is a sloppy meaningless word in this context. What we should say is "comfortable" or "what I'm used to".
OK something stuck in your ears or clamped over them is un-natural duh!