Airbus noise question
A bit of an anorak question from a curious passenger, but:
On an A320 recently, we were, I'd say, a good 20ish miles out from the airport and descending, when a noise suddenly started as if something had disturbed the airflow, accompanied by (very mild) buffeting.
My wife, who is a very nervous flier, asked me what the noise was, and I automatically replied "spoilers", but when I looked out at the wing, everything appeared clean (spoilers down, flaps/slats up). This noise continued until it was eventually drowned out by the sound of flaps, gear etc.
Could a pilot out there suggest what the noise might have been?