Hi Petra, tones for me the last few weeks have gotten very confusing. But, I did have a left ear tone, crystal clear, at 3:51 am the 28th., lasting 20 secs. I think it was Seattle, but, now see at the same time, a 2.1 quake at Coso. This is not the first time, several have been like that lately, almost like they have switched sides?? If that makes sense, anywho a curiousity I am looking at. Did have another on the 21st that could also have been Seattle? The timing fits just right for me. I just haven't kept very good track of these the last 4 or 5 months. I am now, and hope I can keep it up. There is also, this quake: 3.0 2001/03/01 10:22:48 40.514N 123.863W 20.6 20 km (12 mi) E of Hydesville, CA

which could also fit the more recent tone. Any chance yours went with this?

Did you have a pressure along with that tone? As far as, "sound suddenly spread out", when I have a sound that gets "wider" it generally covers a wider area and is further out. If that's of any help.

As far as the math, too far over my head. I'm too right brain. Good luck on your research.

Bye for now.

Mary Maya