It seems like a prime example of where "show don't tell" comes into play. The gun went off... BANG... and the perp dropped like a sack of potatoes. versus Singer raised his sidearm and drew a bead. The shot echoed off the alley walls; sleeping pigeons took to flight, their wings casting shadowy flickers against the aged brick. The bullet struck home. The perp fell in a heap, silent except for the clatter of his over-sized gun as it hit the pavement. Singer moved to stand over the cooling body, and thought once again how his lightweight nine again won a race over a showy-but-heavy forty-five. Tough way to learn a lesson. OK, I'm having a bit of fun here (couldn't help myself). As many have said, it depends on how you want your text to read. Personally I prefer more description than onomatopoeia provide, but (as Singer muses above) sometimes speed is the winner.
But what about using “BANG” without omitting the long descriptive sentences in your example 2? Or incorporating “BANG” somewhere into your example 2. Using the onomatopoeia doesn’t have to compromise having those long or descriptively beautiful sentences. You can have both. Why not?
If that fits into the verve of your writing style, then go for it. I will say that, like salt, a little goes a long way, and a little more goes way too far.
I gotta go with @dbesim on this one. You said "BOO" in the first example and explained what a ghost is in the second.
It depends on the gun, really. A .22 rifle will snap, a flintlock will swoosh, a 9mm pistol will bang and a 7.62 carbine will roar or tremble. Unless your character's got no ear protection. Then they all gonna ring until the point you won't have to describe their sounds anymore.
