The Remote alarm is so loud that it makes everyone onboard jump. Is there anyway I can reduce the output?
Not easily. The piezzo siren used for External alarm is specified to be completely waterproof. Wrapping tape around it doesn’t help much. This is all by design. A better solution is to find out why the system is going off. If it is a false alarm then it needs to be fixed or if it is crew disappearing without putting their PTX back then perhaps some procedural change will help. If you must alter it, bear in mind that it has to always be loud enough to be heard above an engine(s) at full throttle and a 60 knot storm if it is going to protect your crew.