I've been doing a whole lot of Audio Mastering lately and I was just reminded today that one of the methods I use in the process I actually learned from a deaf person. You just said "Say what??" or something similar. Let me explain.
When I first got out of college I was a substitute teacher by day and a live and studio sound engineer and performer by night. I was asked to cover the "Deaf" class for a couple of months while the teacher was on leave. I wasn't certified or anything but they were really short staffed, so I gladly took the assignment. The kids were awesome and I learned a little sign language but more importantly I learned how some deaf people enjoy music by "feeling" it. Most of the kids in the class were into Heavy Metal and they wanted me to do sound at an all ages show for one their friend's bands, which I did.
My students were all psyched to see me and the show. I noticed while I was checking the kick drum and bass that a few of the deaf students went and sat on or put their hands on the huge subwoofers at the foot of the stage. They told me later that that's how they "hear" the music-through the low end vibrations coursing through the subs. I thought this was amazing and was very happy that they could enjoy music that way.
That being said, one of the methods I use while mastering is actually putting my ear and hands on my subwoofers and feeling the vibrations off various objects in my studio. With this method I can tell if the bass is too intense or not intense enough. It's certainly not the deciding factor in the final product, but it helps.
I've always felt that you can learn a lot about the visual world from a blind person and a lot about the auditory world from a deaf person and the list goes on...