For a general loudness:
* A roar: This metaphor suggests a powerful and intense sound, like the roar of a lion or a crowd.
* A blast: This metaphor implies a sudden and overwhelming sound, like an explosion.
* A cacophony: This metaphor suggests a confusing and unpleasant mix of sounds, like a noisy market.
* A clamor: This metaphor emphasizes the disruptive and chaotic nature of the sound, like the clamor of a construction site.
* A din: This metaphor suggests a constant and irritating sound, like the din of traffic.
For a loud voice:
* A trumpet: This metaphor emphasizes the clear and commanding nature of the voice.
* A thunderclap: This metaphor suggests a loud and impactful voice, like a clap of thunder.
* A cannon: This metaphor implies a powerful and intimidating voice.
For loud music:
* A tidal wave: This metaphor suggests the overwhelming and powerful nature of the music.
* A hurricane: This metaphor emphasizes the intensity and energy of the music.
* An earthquake: This metaphor suggests the powerful and shaking nature of the music.
For other types of loudness:
* A siren: This metaphor suggests a high-pitched and urgent sound, like a siren's wail.
* A jackhammer: This metaphor implies a loud and relentless sound, like a jackhammer.
* A gunshot: This metaphor suggests a sudden and sharp sound, like a gunshot.
Ultimately, the best metaphor to use will depend on the specific context and the effect you want to achieve.