Here I am in the south of 86 (close to Adriers), minding my own business, when I become aware of a sound, just after 10am, becoming louder. It sounded like a large jet aircraft, but at close quarters - very bassy. The sound grew in volume for a good 4-5 minutes then gradually diminished. The sound was audible for about 12-15 minutes.
At its peak, it was very loud - certainly loud enough to drown out a conversation. The direction of the sound was difficult to make out but I’d guess it was somewhere to the north-west of me.
The really odd thing was that there was only one aircraft to be seen. That, according to my flight tracking software, was a Ryanair 737 about 10 miles away, and the noise was FAR too loud to have come from that.
We had something similar yesterday and it looked like two North American B-25 Mitchells, flying very close and quite low, lumbering along.
Checked both my flight tracking apps but nothing was showing up .
Twin prop with twin tails on them, could not see any of the markings on them as they were flying into the sun, weird.
I haven’t seen a Mitchell in flight since an airshow at Duxford UK in 2013 or thereabouts!
It sounded like a high velocity gas stream (jet or rocket engine) rather than prop or turbo-prop. The sound was constant in volume for a good 8-10 minutes. In that time an aircraft would have covered at least 30km, and possibly as much as 100km so the volume would have varied, unless it was invisible and flying at a constant radius from me!
I did wonder if it could be related to our local nuclear power station (30km distant) but I can see the cooling towers from the high bit of our garden and there weren’t any mushroom clouds to be seen
It did sound like an engine/afterburner test (I’ve filmed them at various aviation factories over the years so know what they’re like albeit through ear plugs and ear defenders!) but the nearest military base (Cognac) is 110km away and the nearest civil (Limoges and Poitiers) about 60km.
I have a friend who lives about half way between your place and mine (about 20km from each of us) and he reported the same very loud noise. He found it quite disturbing.
Perhaps you need to get your ears checked