This block is part of the soundSensor object
By default a sensor's "change" event fires every time the sensor value changes at all, even by one. The light and sound sensors are constantly fluctuating, so you probably want the "change" event to be a little less responsive. The threshold property allows you to set how much a sensor should change before considering it a "change" event - so setting soundSensor.threshold = 100 would cause the sound sensor's "change" event only to trigger if its value increased or decreased by at least 100.
soundSensor.threshold = someNumber
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