They work by increasing the volume of the background noise. Sounds that would normally affect or you sleep end up blending in with the background noise.
http://mynoise.net/NoiseMachines/throatSingingDroneGenerator...
I use that one, Darkness, overall volume up a little and first two sliders down a little. Works like a charm.
German company, but available in the US: http://www.amazon.com/Ohropax-Reusable-cotton-Plugs-Carrying...
I tried two pairs of these Radians and couldn't get them to work well. They don't form a proper seal I think, not exactly sure. Def. not as effective as normal ear plugs when it comes to blocking out sound for me. I'm not sure if I did something wrong during the molding process or my ear shape is somehow incompatible with them but I did carefully try twice to no avail.
Any tips?
I may look into getting some custom molded silicone sleep plugs in the future, I have some noise attenuating ones already for concerts and they're pretty comfortable.
http://www.homedepot.com/p/3M-Orange-Disposable-Earplugs-7-P...
You can take a pair of scissors and slightly trim from the big (non-rounded) end, so that they aren't long enough to interfere with side sleeping, but they are still long enough that you can easily pull them out in the morning.
I haven't tried custom silicone earplugs, but these disposable ones are very soft and comfortable. You twirl them into a smaller thickness and they gently expand once you insert them.
I started using them a number of years ago when the guy in the house next door got a very loud dog that he insisted stay outside at night and/or early morning. So of course the dog did nothing but whine and bark! Fortunately he finally got rid of the dog.
A single "disposable" pair of plugs can last a week, or even a month if you want. The sound effectiveness decreases slightly over multiple uses. But that's OK. They start out really quiet, they claim something close to 30 dB. So if they're only 15 dB after multiple uses, that's OK. You probably don't want total isolation anyway.
It looks like it's not earplugs, but sensory deprivation that can cause tinnitus. If you're listening to a normal volume of noise for at least a few hours a days, it won't be a problem.
For me, I'll have to try using earplugs more, but the stress on my ears isn't so nice because I'm a side sleeper. I wish I could just go to bed earlier, but I work on a remote team which is half in LA, and it would be counterproductive if I wasn't able to stay up past 10-11 PM... not to mention my schedule would conflict with that of my friends and roommates.