Silencio!

The first thing I noticed when I put the earplugs in was that I could hear/feel my heartbeat. My assumption is that this is an 'artifact' of the ear protector: because it touches the sides of my ears, it transfers those vibrations into pressure changes which I can sense. I also notice a rather loud "thump...thump" as I walk. I think this is due to the same thing (i.e. the vibrations caused by my footsteps travel through my body and "through" the ear protector, causing me to sense them more than I would otherwise).

By accident I also discovered that when I tilt my head down so that my face is parallel to the floor, I hear a distinct rushing sound. The only thing I can figure out is that this is the blood rushing into my head; I would expect this to happen if I put my head between my knees, but I was surprised it happened with even a slight tilt. I am also amazed that I can hear it (if that is truly what I'm hearing).

Right now I notice that although I know there is a radio on, and someone is occasionally singing along, I hear it only faintly. It's country music, and I'm assuming there are drums playing, but although I can sort of hear the whole music faintly, I don't hear any drums. This makes sense, though, considering that these ear protectors cause more attenuation at higher frequencies, where most drums (e.g. snare and cymbals) are.

One thing that I can hear surprisingly well is my computer keyboard as I type on it. I can even hear other keyboards in the same room. While this sound seems muffled like everything else, I don't notice it as being very much softer. This is interesting because the 'clicks' of the keys seem to me to be slightly higher frequency, where the earplugs attenuate more. At first I thought that perhaps it was due to the earplugs themselves helping to transmit the sound acoustical disturbance to my ears. But I rejected this hypothesis because I can hear the keyboards of other people fairly well too.

Of the sounds I do hear, I find that it is more difficult to tell which direction they are coming from. The radio that's playing, for example, sounds like it is coming out of the ventilation duct directly above my head, or perhaps through the wall in front of me (in actuality it is coming from behind me, to my left). However, I can identify accurately where the keyboards noises are coming from.

My greatest fear came while I was eating lunch. I suddenly realized that I had no way of knowing whether I was smacking my lips or chewing loudly or anything else that I normally take for granted I won't do. Hearing provides us not only with information about the 'external' world, but also gives us feedback about ourselves, and our own actions.

Finally, I had a friend check my hearing using a pure tone audiometric test (the kind where you raise your hand when you hear the tone). My right ear results are listed below, without the earplugs (which was done at the beginning of the semester) and with earplugs. The numbers represent the least number of decibels I was able to hear a tone at for each frequency. The attenuation we measured is approximately the same as that listed on the course web page: