I also listen to noise instead of music to block outside sound. I use sox on mac/linux/windows to generate brown noise which I find less tiresome than white noise.

Sox is well documented but here is the command I use for 90 minutes of brown noise (I try to get up and walk for a minute each time it finishes).

play -n synth 90:00 brownnoise brownnoise

Just a suggestion -- I don't like most headphones, but I have a set of Sennheiser HD-202's that I bought years ago that are really comfortable for long times. It's especially odd, because they only go partially over my ear, not fully over like the really big headphones, but they are still comfortable and work well to cut down on noise.

I often use mynoise.net, but after a while my ears just need a rest -- both physically and aurally. BTW, I have two different pairs: big Audio Technica studio monitor phones, and a pair of Beats studio monitor phones that were given to me as a gift.