code:

on *:text:!massdevoice*:#: {
  if (($nick isop $chan || $nick ishop $chan)) {
    var %Devoice.intVoices = $Nick(#,0,v)
    While (%Devoice.intVoices != 0) { 
      mode $chan -v $nick(#,%Devoice.intVoices,v)
      dec %Devoice.intVoices 
    }
  }
}

on *:text:!massvoice*:#: {
  if (($nick isop $chan || $nick ishop $chan)) {
    var %voice.intVoices = $Nick(#,0,v)
    While (%voice.intVoices != 0) { 
      mode $chan +v $nick(#,%voice.intVoices,v)
      dec %voice.intVoices 
    }
  }
}