The 1 audible "bong" could be low outside temperature warning which bongs at 37 degrees. The other Bong could be the clock alarm going off. (Took me a while to find that one.)
Sometime you can get a signal if theres a system fault which will show up in the OBC window.

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"What you hear in a great jazz band is the sound of democracy. “The jazz band works best when participation is shaped by intelligent communication.”
Harmony happens whenever different parts get to form a whole by means of congruity, concord, symetry, consistency, conformity, correspondence, agreement, accord, unity, consonance…….