Ambiences work in a most primal way. They can speak directly to our brain subconsciously.
So, birds chirping outside your window may indicate normality,
perhaps because, as a species, we've been used to that sound every morning for millions of years.
On the other hand, industrial sounds have been introduced to us a little more recently.
Even though I really like them personally
they've been used by one of my heroes, David Lynch, and his sound designer, Alan Splet
industrial sounds often carry negative connotations.
Now, sound effects can tap into our emotional memory.
Occasionally, they can be so significant that they become a character in a movie.
The sound of thunder may indicate divine intervention or anger.
Church bells can remind us of the passing of time, or perhaps our own mortality.
And breaking of glass can indicate the end of a relationship or a friendship.
Scientists believe that dissonant sounds, for example, brass or wind instruments played very loud,
may remind us of animal howls in nature and therefore create a sense of irritation or fear.