Your central air conditioner may make a loud noise when it comes on. This is because it may have a leak somewhere in the system.
Loud noise is not a good description. If its a loud squeal turn the air conditioner or defroster off. If the squeals goes away the compressor or the clutch for the air conditioner compressor is locked up.
repace the fan belt that drives the a/c unit. If it doesn't fix it, it's the a/c pump. Very costly. Live with the noise.
howling
If it's a creaking noise then it is most likely that your compressor is broken.
You need to wash it.
A vehicle's starter will being making a loud screeching noise if it does not align properly with the flywheel. It slams against the flywheel and grinds against the surface.
Certain things may make you flinch. If loud noises bother you, have people surprise you by making a loud noise. When you get use to noise, you will less likely react when the noise occurs.
Listen to it. if it is making loud noise you will hear it... assuming by noise you mean sound wave vibrations within the range of human detection...
If the 1999 Suburban noise is a sort of loud banging noise, the problem could be that the engine have jumped time. Jumping time would cause the noise and jerking in the engine.
Unplug everything, replug it back in.
Your A/C belt is loose and needs to be tightend or replaced.