>>12379946>>12380048There is a difference between changing your voice and projecting it. Also EQ and the type of microphone matter.
No streamer has a 100% natural voice because all streamers project their voice to some extent. To get a natural unprojected voice you would need to have the microphone 5 centimeters from your mouth. If you don't have it like that and you don't project your voice, your audio will suck. I'm sure you've seen someone shy talking on TV. They sound awful because they don't do that.
By projecting your voice, you make it travel more distance to your mic, so you need to boost your treble (which we do unconsciously). That's not changing your voice, that's a good use of a microphone.
You have specific cases where a projected voice is naturally deep, like Mori's, but those are exceptions. In Ame's case, besides projecting, she has a particular EQ that boosts her highs and cuts her lows
Also, the emotional state and context changes the tone of your voice. If you are happy or you want to explain something in a way that people trust you, your pitch becomes sharper. Just look at nature review. Physiology stuff 
