Just saw and heard this. I was aware of this tradition, but hadn’t thought to try to find recordings or videos on the ‘net.
Check it out! I found it on “Neuropoetics: The science of prayer and other pursuits – with gratitude.” It’s a recording of a semantron (pounding on a plank) calling monastics to prayer! How cool is that? And oh, so traditional – dates back to the early Church and predated bells.