These home-made hifi headphones work as well or better than Sony or Bose noise-cancelling headphones. Cost: $20 Time to make: one minute. Difficulty: none.
Unlike the commercial products, these block outside noise instead of cancelling it. Listen to music or books on tape without hearing traffic noise, screaming babies, etc. I’ve been making these for more than a decade. People sometimes ask “isn’t it dangerous not being able to hear” No. Talking on a cellphone shuts off most of the brain whereas listening to headphones is no more dangerous than say, being deaf. Lots of my friends use these units and no harm has come to anyone.