Good questions. From others and myself, one ear "hears" local EQ and the other the world. The duration of tone will mean one of two things. Either the quake will be close to you or of some size and distance from you. The tone is usually the last signal we get before the quake. Prior to it, some of us get what sounds like clicks; the main shock and aftershocks. Ringing, singing, static can mean a number of different things, but, as related to EQs, they are related to magma movement...as far as I have determined.