Sorry if there is already a solution to this, I don’t really know how to describe it so it was hard to search for.
Heres a sample of what I want to achieve.
http://www.youtube.com/watch?v=dpBWdNXCqfY
What (in words) do you want to achieve? A man talking inside a space suit?
Gale
In-helmet-voice-effect here … https://forum.audacityteam.org/t/gas-mask-effect/17407/6
[ However that youtube video doesn’t sound like that ].