megaphone
noun
a cone-shaped device for magnifying or directing the voice, chiefly used in addressing a large audience out of doors or in calling to someone at a distance.
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Bert Wainwright's voice came down the pipe, sounding megaphonically close.
From The Little Lady of the Big House by Jack London