The Airbus A320 Family is know for their weird sounds (The famous Barking Dog (the PTU of the A32F and the Whistle)
The whistling sound is also produced when the aircraft is at a very low altitude:
Aegean A320 (SX-DGW) on final at Belgrade Airport in 2016
When an another rework of the A320 Family is confirmed, I hope that they will get the CFM56 and the IAE Engines sound (and the Whistle too, but it should be a Setting Option)
#AddTheA320FamilyWhistlingNoise