The phrase "sounds one horn" refers to the act of announcing something or drawing attention to a particular matter. There are various synonyms for this phrase, including "blows one's trumpet," "rings the alarm," "announces," "proclaims," and "declares." These synonyms reflect the different contexts and tones in which one may use the phrase. For instance, "blows one's trumpet" may be used in a boastful or self-promoting manner, while "rings the alarm" conveys a sense of urgency or danger. Ultimately, the choice of synonym depends on the intended meaning and the effect one wishes to create in their communication.