nails on a chalkboard

feedback

feedback loop

speaker feedback

horror effect

horror sound

terror

digital feedback

audio feedback

screeching

piercing

ear-piercing

oscillating

electronic

electric

harsh

grating

rasping

jarring

loud

shrill

strident

angry

anxious

aggressive

calm

chaotic

dark

disturbing

dramatic

dreamy

energetic

epic

frantic

futuristic

haunting

high tech

hypnotic

industrial

mechanical

ominous

foreboding

powerful

repetitive

suspense

tension