Startlingly loud noise, part two. This happened about ten minutes ago.
Downstairs, checking on Tigger, and locking up, and grabbing snacks to aid writing, and feeding the feral cat who's adopted us. Just as I'm setting their small meal down I hear a really loud sound I can best describe as a sharp crack. Thinking back over it, it sounded like an impact, like something being hit, or falling to the floor. First (very) minor strangeness: I couldn't pinpoint where it came from, other than the sheer volume suggesting it was pretty close by.
Slightly less minor strangeness. Spent several minutes exploring the lower floor of the house, looking for the source of the sound, and found nothing. No breakages, nothing fallen, nothing out of place. Wondered if it might be to do with our Henry vacuum, sitting with his attachments piled around and on him in the next room, but tests showed otherwise. The only hypothesis I have involves a chimney part way through being cleaned out ready for winter; maybe something had dislodged from inside it and fallen into the plastic box currently sitting under the open flue; however, would it have been so loud from two rooms away?
The cat didn't seem to react, by the way, and Tigs didn't budge from her sofa, so maybe it was all in my head? A random auditory hallucination?