"Split the eardrums" is an intense phrase that describes a loud and deafening sound that can cause pain and discomfort. Some synonyms for this phrase could be "deafening roar," "ear-piercing screech," "thunderous boom," or "shattering noise." Another way to describe a sound that is as loud as the "splitting of eardrums" could be "a cacophony of sound," which conveys a loud and jarring mixture of sounds. Whatever phrase or synonym you choose to use, be sure it communicates the forceful and overwhelming nature of an intense sound that impacts the ears.