The movie Backdraft employs sound sweetening techniques, by layering animal noises over the top of roaring fire to instil a subconscious, primitive fear in the user. With roaring lions and shrieking monkeys, Backdraft implements a multitude of subtle and overt sounds to create an excitement and they are balanced in a way that doesn’t pull focus from the theme but actually intensifies it!
Using animalistic sounds in this context works because of our already learned, subconscious connections. We already know that a loud lion roar is scary. It sounds scary! and that’s because we’ve already learned this. So when we hear this sound out of context, we don’t immediately connect it to the conscious memory of a lion but the subconscious connection of the emotion of fear, because this cognitive path is shorter and is therefore received quicker. Think RAM.
To implement this I gathered a few animal sounds that I felt could work throughout the film, that correlated to certain themes. I then sprinkled these around and found that they worked well in a few places. When I found there resting place, I dragged them around a little until it felt right, and then started processing them a little. To make them stand up against the surrounding sounds, I parallel compressed the sounds to make them sit in the mix. I then bussed them to a fairly sparse reverb. I then juxtaposed this against a shiny wavetable synth in serum. The sounds that I used are a lot less aggressive and this resulted in them sounding better in more serene, less dark atmosphere.
Jordan Vaughan: Creative Sound Design 