* For the shell:
* Land snail: If you're talking about the marine snail that produces the conch shell, a land snail could be seen as an opposite.
* Other types of shells: You could say "whelk" or "clam" depending on the specific type of shell you're referring to.
* For the sound:
* Silence: The conch is known for its loud, distinct sound, so silence would be the complete opposite.
* Other sounds: You could use any other type of sound, like a bird call, a whisper, or music, depending on the specific context.
* For the instrument:
* Other instruments: If you're talking about the conch as a musical instrument, you could use any other instrument, like a flute, a drum, or a guitar.
To give you the most accurate antonym, please provide more context about how you are using the word "conch."