Loud, stentorian, earsplitting, hoarse, raucous, strident, stertorous are comparable when they apply to sounds and mean great in volume or unpleasant in effect.
Loud suggests a volume above normal and sometimes implies undue vehemence or obtrusiveness.
Stentorian, chiefly applying to voices, implies exceedingly great power and range.
Earsplitting adds the idea of a physically oppressive loudness, especially shrillness (as of screams or shrieks).
Hoarse implies harshness, huskiness, or roughness of tone, sometimes suggesting an accompanying or causal loudness.
Raucous implies a loud, harsh, grating tone, especially of voice, often implying rowdiness.
Strident adds to raucous the idea of a rasping, discordant but insistent quality, especially of voice.
Stertorous, usually not applied to sounds made by the voice, suggests the loud snoring, or sounds like snoring made in breathing, especially when it is difficult, by persons or animals in sleep, in a coma, or with marked asthmatic difficulties.