For voice precedence 5 is ok, for signal match value cs3, af31 and all other traffic should be in fair-que. Follow the below example:
class-map match-all voice
match ip dscp ef
!
class-map match-any signal
match ip dscp cs3
match ip dscp af31
!
policy-map r1
class voice
priority percent xx
class signal
bandwidth percent x
class class-default
fair-queue