Another word for loud
Having volume of sound
deafening, ringing, ear-rending, ear-piercing, ear-splitting, booming, fulminating, intense, resounding, piercing, high-sounding, trumpet-toned, blaring, sonorous, resonant, crashing, deep, full, powerful, emphatic, vehement, thundering, heavy, big, deep-toned, full-tongued, roaring, strident, enough to wake the dead*; see also shrill.
Producing loud sounds
clamorous, noisy, uproarious, blatant, vociferous, stentorian, bombastic, turbulent, tumultuous, blustering, clarion-voiced, lusty, loud-voiced, boisterous, obstreperous, rambunctious, cacophonous, raucous, loud-tongued; see also harsh 1.
Antonyms quiet*, soft-voiced, calm.
*Lacking manners and refinement
*Flashy, used of colors or taste in color