The Collaborative International Dictionary of English v.0.48:

Earshot \Ear"shot`\, n.
   Reach of the ear; distance at which words may be heard.
   --Dryden.
   [1913 Webster]

WordNet (r) 3.0 (2006):

earshot
    n 1: the range within which a voice can be heard; "the children
         were told to stay within earshot" [syn: earshot,
         earreach, hearing]

Moby Thesaurus II by Grady Ward, 1.0:

29 Moby Thesaurus words for "earshot":
   ace, auditory range, bit, bowshot, brief span, carrying distance,
   close quarters, close range, crack, earreach, gunshot, hair,
   hair space, hairbreadth, hairsbreadth, hearing, inch, little,
   little ways, pistol shot, range, reach, short distance,
   short piece, short way, sound, span, spitting distance, step