Both Uses

distinct
in
Holes, by Louis Sachar
(Edited)

They were still too far away to see the camp, but he could hear a blend of indistinct voices.
p. 196.7 *

indistinct = not clear or easily identifiable

standard prefix: The prefix "in-" in indistinct means not and reverses the meaning of distinct. This is the same pattern you see in words like invisible, incomplete, and insecure.
As they got closer he occasionally could hear Mr. Sir's distinctive bark.
p. 196.8

distinctive = clear, easily noticed, and/or identifiable as different or separate -- sometimes to indicate a difference that is excellent

Definitions:

(1) (distinct)
clear, easily noticed, and/or identifiable as different or separate
(2) (meaning too rare to warrant focus)