I have no experience with such devices but the comment made by the blogs author
"mounting the unit on a SCRAM cart that has a battery and wheels but you still would have to lug it from one bridge wing to another."illustrates to me the unanticipated problems encountered in practice.
This article at Defense Update mentions that a LRAD was used to defend the Seabourn Spirit in Nov 2005. In that case the attackers used machine guns and RPGs. The operator of the LRAD was injured in the attack. The ship also increased speed and took evasive maneuvers. The role of the LRAD is not clear.