def ar(
        cls,
        trigger=0,
        ):
        """
        Constructs an audio-rate Timer.

        ::

            >>> timer = supriya.ugens.Timer.ar(
            ...     trigger=0,
            ...     )
            >>> timer
            Timer.ar()

        Returns ugen graph.
        """
        import supriya.synthdefs
        calculation_rate = supriya.CalculationRate.AUDIO
        ugen = cls._new_expanded(
            calculation_rate=calculation_rate,
            trigger=trigger,
            )
        return ugen