| deep(adjective, weak, intense, pale) |
| contralto(adjective, strong, hard, deep) |
| bass(adjective, strong, hard, deep) |
| alto(adjective, strong, hard, deep) |
| quiet(adjective, calm, dull, close, weak) |
| faint(adjective, calm, weak, moderate) |
| soft(adjective, calm, dull, close, quiet) |
| subdued(adjective, calm, dull, close, quiet) |
| whispered(adjective, weak, deep, pale) |
| buttoned up(expression, adjective, close, quiet, soft) |
| clammed up(expression, adjective, close, quiet, soft) |
| close(adjective, quiet, soft, peaceful) |
| close-mouthed(adjective, close, quiet, soft) |
| could hear a pin drop(expression, adjective, idiom, close, quiet) |
| dumb(adjective, close, quiet, soft) |
| hushed(adjective, calm, dull, close, quiet) |
| hushful(adjective, close, quiet, soft) |
| inaudible(adjective, dull, close, quiet, weak) |
| inobtrusive(adjective, quiet, soft) |
| muffled(adjective, dull, close, quiet, weak) |