I’ve had this same problem for 15 years and finally spoke to my friend who is an engineer about it. I said there must be something we can make to stop the whistling noise. He took on the challenge and we created a ladder cap/plug to plug up the holes on the ladder.
After a year of prototypes and planning, we now have a product ready for purchase to solve this problem. For a small investment you can end that noise for the lifetime of your ladder! We’ve just launched this week and to celebrate we are offering free shipping within Australia. Just enter freeship23 into the coupon section of the checkout page to redeem.
We would love you to check out our online shop at www.noisend.com.au