Film Sound Cliches:
Weapons:
A fired gun never recoils.
Guns (handguns, rifles, machineguns etc) have a really deep "BOOOMMM!!" sound not a "CRACK!". Also, the there's old cliche about the number of rounds the average magazine holds, the good guys almost never run out of ammo, and they seem to be able to use a handgun accurately to over a 100 meter range (accuracy of weapons over distance is pretty much a factor of barrel length - handguns are for CLOSE distances).
All sub machine guns sound alike and have the same rate of fire
Machine guns and their rate of fire ... most users of these weapons can manage to sustain over 10 second continuous rate of fire (in actuality, you are supposed to fire the things in short bursts -- after a long burst the barrel will heat up so much the weapon will jam). Also I have never ever seen any protagonist change a MGs *barrel* no matter how long he has used the MG. (the barrels overheat, and also sustain incrediable wear requiring these to be changed -- often in battle, the gunner's mate will carry spare barrels as well as the inexhaustible ammo supply which weighs next-to-nothing). Esp. WW2 era weapons.
Bullets always ricochet, and they must travel pretty slow because the "rico" is 1/2 second later after it moves 50 feet
All bullets make a distinct riccochet sound and when flying past you they make a zip noise when in fact they are moving faster than the speed of sound and in real life would produce a whip lash or bang sound
Handguns: All handguns make a frightening clicking sound when handled as though to suggest that the parts are loose. The more advanced the gun (Men in Black) the louder, and more varried, the clicking. In real life any gun making noises like that would probably explode in your hand with the first discharge. Note: All energy type weapons will power up with a loud hum.
HELICOPTERS & AIRPLANES:
Helicopters always fly from surround to front-speakers.
People standing outside a running helicopter can always talk in normal or just slightly louder than normal voices
Every helicopter shutting down emits the chirp-chirp-chirp sound of the rubber drive belts disengaging, in spite of the fact that only the famous Bell 47G (the Mash chopper) actually makes this sound.
Piston helicopters always start up with screaming turbine engine sounds.
An approaching airplane or helicopter will make no noise until it is directly over the characters, at which point it will suddenly become thunderingly loud.
Characters will never hear an approaching airplane or helicopter, even though in real life you would hear them approaching for at least a minute before they were close enough to see. This also holds true for approaching armies on horseback and tank battallions.
The tires of any jet screech upon landing
Any airplane in a dive will make a whining noise that will get louder and higher-pitched the longer the dive lasts.