The Sound of the Bell
At the end of a meditation session, a monk or leader generally rings a bell. It’s been said that this is the only time that you’ve actually meditated, when the bell is rung.
This is because you’ve spent the last however many minutes in a cycle of mind redirection, of your mind wandering and of bringing it back to the present moment. It’s a self-regulated exercise for everyone in the room. Each person, at any point in the meditation is either coming back to the present (waking up) or getting lost in thought (sleeping). Until, at the very end of the session…
The bell rings. And every single person in the room experiences waking up together. In the same way that shavasana (sleep pose in Yoga) brings the results of your practice into being, so too does the bell at the end of zazen. And, for that matter, so does the bell that literally wakes you in the morning, or the one that signals you to change classes in high school. (How many times have you fallen asleep in class until the bell rings?)
Although I own a singing bowl to produce pure sound, I use the Insight Timer app on most days. It seems to have the same effect.