I have one-an older model - and it is loud.
One possible word of caution (this from the guy in the LDS where I bought it): If you plan to use it, to protect your hearing, reach high with the arm holding the inflator hose, aim the horn away from you, and, if possible, keep your head under water, and/or use the shoulder on that same side to help cover that ear.
I know that his bit advice sounds like one that only a contortionist could follow, but the guy seemed sincere, and demonstrated the somewhat strange posture he described. Also, he would not activate the dive alert in the shop! ????
Salesmanship/a wicked, yet warped, sense of humor, or good advice?????
In any event, if the choices are "hearing problems" or "lost at sea"...........