How do you generally go about describing noises to an audience? Do you resort to onomatopoeia or do you use an alternative or mix the two? If you use onomatopoeia, would you italicize it? I'm specifically thinking in terms of a helicopter like noise, but I think talking in general terms is also useful.
I generally just describe them. I can't think of a time where I would make an actually sound effect of the helicopter. Just put in with the sentence.
Depends on the POV and the scene, but i prefer descriptive rather than straight out "crash", "bang", "eek" kind of stuff. She jumped at the loud bang of the car backfiring. The wailing siren split the night. Jake crashed through the skylight.
I would keep it simple. The more precise you try to be the more you will confuse and annoy your reader. So no 'schushche scheusche schushche went the helicopter blades...' - otherwise your reader will spend more time trying to work out how to pronounce the word then they will appreciating the scene. The helicopter blades whirred above her head. That's about all your need.
Maybe put some emotion into the noise I figure. That way you can have a nice effect on the narrative style or your story works better.
I had more of a "thwap, thwap" going, but maybe I'll take it out. It's really a giant bird creature attacking my MC, but she thinks it's a helicopter. So I guess maybe saying that it sounded like a helicopter is enough, although a "whir" might be good.
