In UT2004 there is a client-side sound setting controlling, how the volume of sounds falls of when moving away from the sound source. This so-called Rolloff value can be changed in UT2004.ini and with a console command in a way that allows to clearly hear sounds from the opposite side of the map.
"Lock Rolloff" is a server actor that enforces a minimum rolloff value of 0.4 (the default INI value is 0.5) and additionally makes it impossible to change Rolloff while connected to the server.
This server actor is already running on the
inUnreal.de 1on1 Server and can be downloaded either in the
UnrealAdmin.org download area or from
my homepage.
Since Lock Rolloff is not a mutator, it will
not prevent your server from being "standard".