Interesting. What do you think it might be? I'm a fellow northern Californian.
People may laugh at this, but I don't think it is bigfoot. I've seen 2, probably a 3rd. I follow up on reports, I go look for them. Despite KNOWING they're there, I give less than 50% chance that's what I heard.
It doesn't sound like them. No scream, no yell, no holler. From 2-1/4 miles minimum, it was a loud "ahhhhh" sound like the doc tells you to make, maybe a little bit lower, more "breath-y" (if you've had voice lessons, you'll understand), and at that distance, still had a remaining volume about equivalent of two people standing 10 feet apart talking at a comfortable level.
I have that on audio recorder.
I may well be crazy, but my audio recorder isn't, it's just a machine.
I dunno. I really don't know. I can't think of anything reasonable that it could be. I'm not even sure I can think of anything UN-reasonable it could be, but I'm stuck with that audio recording.
There IS something out there. Heard it twice.
Tom