be, sound
turn sth up
She turned the radio up loud.

extremely, fairly, very, etc.
deafeningly, incredibly, unbearably
annoyingly
unnaturally
Her voice sounded unnaturally loud.

loud and clear
Tommy's voice came loud and clear from the back row.

Loud is used with these nouns:
applause, bang, bark, bass, bell, bellow, blast, boo, boom, bump, buzz, call, chatter, cheer, clang, clank, clatter, click, colour, commotion, crack, crash, creak, cry, curse, echo, exclamation, explosion, footstep, gasp, groan, growl, grunt, gulp, hammering, hiccup, hiss, howl, knock, laugh, laughter, moan, music, noise, ovation, passage, peal, pop, roar, rumble, scream, shout, shriek, sigh, smack, smash, sniff, snort, sob, sound, splash, thud, thump, thunder, tie, voice, volume, wail, whisper, whistle, yawn, yelp

Loud is used with these verbs:
sing