After reading this thread, I decided to buy the JD noise cancellation headphones. I have to say that I am very impressed. They do exactly as advertised, which is reduce low frequency noise (e.g. the engine of a lawn mower or tractor, ....). I first tried mine on my ExMark, which is especially noisy, and it really makes a big difference. Also works for the JD tractor, 2 cycle weed trimmer and hedge clippers. The material that came with the headphones claim that they reduce noise by 18 dB. That is really good, since a 3 dB reduction would reduce the noise intensity by 1/2. So I calculated that 18 dB works out to be an intensity reduction of 1/64, which is very good. Cuts the noise reaching my ears by 1/64. By the way, previously I was using headphones I bought for hearing protection at the shooting range, and the JD phones are a big improvement.
My hearing seems to get a little worse every year so I bought these to slow my hearing loss. I highly recommend them for that.
Eddie