Day Night script adds a normal day/Night cycle with the posibility to add Elements (lights) to turn it in and off based on the cycle.
The hours can be changed on the line:
bool isDaytime = (timeOfDay >= 6 && timeOfDay < 18);
Sound trigger acts similar by activating GameObjects (serialized in editor) with time range handlers. With this script any object can be activated Not only sounds, since it activates a GameObject that has an Audiosource (Loop and Play on awake should be checked)
Sound trigger access to DayNightCycle to know the day hour.