You must be careful with fence design.
Whistling balcony railings at a new Grey Lynn apartment block are drawing neighbourhood complaints, with people coming from blocks away to investigate.
“When it gets really bad, you get to screaming point,” said Sherrol Manton, a retired accountant, 71. “We get on the bus, go downtown and have a break.”

Her husband, Howard Manton, a retired builder, concurred. People came from as far as three streets away to investigate the sound and complain about it, he said.
A neighbour, who did not wish to be named, likened the sound to pan pipes, but he said it wasn’t a good sound.
Read more here: NZ Herald – ‘You get to screaming point’ – Grey Lynn whistling balcony neighbour