Alarms are never loud enough on any freediving gauge i know of with a 5 mil suit - that's my experience anyway. I hear them okay with a 3 mil if I'm paying attention.
With a 3mm I don't hear them, to the point I thought my unit was defective. I had to hold the warch against my ear location on the hood until am alarm triggered to understand it was working fine.
Somebody needs to invent a louder underwater speaker thingy.
If they made a rechargable model and added a vibration unit I would be happy.