
I need to know for something I am writing, and perhaps this will also be useful information for others to know.
Oh... I looked in the Wiki llWhisper in the Wiki and got my answer for myself. It says people who are within a ten meter radius of you will be able to hear that whisper. So if you make 4 pie chunks that have a 10 meter radius, and stick them together with their tips interesecting at the source of the sound, then all who are sitting on that (20m diagonal circle) set of objects will be able to hear the whisper and those beyond that will not hear it or be "spammed" by that whisper.