In fact, "listening to the pines" is only the first essential step towards calming the mind. Once one has reached a state of tranquility, one's senses grow more acute, and one can begin to listen to more minute sounds.
「聽松」其實是讓心安靜下來的首要條件，靜而後能有更細微的感覺，能開始去聽更細微的聲音。