Greg Schwartz

11/21/2000

NPSY 12b

Hearing Protectors Experiment

While many of the effects I experienced while wearing sound muffling ear protectors were expected, just as many came as a surprise. Understanding how sound waves and the ear work can offer some insight into some of the fascinating changes that took place during my period of modified audition. Two areas especially intrigued me: the use of different frequencies in hearing, and the role of attention on the perception of different sounds.

I expected to hear quieter voices in normal conversation with the ear plugs in, but I did not expect the change that I heard in the Œshape‚ of peoples voices. At a number of points throughout the day, I would have trouble distinguishing a voice on the telephone or a distant voice in the cafeteria. The problem was not that I was missing many words, but rather, that the frequency gradients of the person‚s voice were not what I had expected. As the table online shows, the ear protectors absorb more high frequency sound than low frequency sound. This is not surprising since the nature of the material of the plugs suggests that, when placed against the eardrum, they will prevent rapid membrane movement more than they will prevent slow movement.

Having difficulty identifying the voices of my family and friends, I was able to realize the importance of frequency (especially high frequency) cues in voice identification. However, the effect of this high frequency attenuation was even more apparent when I wore the protectors during the first few minutes of my Jazz Ensemble rehearsal. While some peoples voices sounded strange, the sounds of my own saxophone and the saxes and horns around me in the band sounded even stranger. I was having such trouble trying to blend in the section and listen for my own pitch that I had to take the protectors off for the sake of musicianship.

Another fascinating part of my day was the discovery of the role of attention in hearing. I was very surprised at the number of sounds that pass by without conscious perception every day. The most striking examples I found were the sounds of my own body. As soon as I put the ear protectors in, I became very aware of the sounds of my breath and my heartbeat. Even more alarming was the sound of the saliva in my mouth when I was eating. All of a sudden, I felt rude for being such a noisy eater. There is a simple explanation for all this, however. While the ear protectors diminished the apparent volume of sound waves against my eardrum, they had no effect on sounds (like internal bodily sounds) whose vibrations effect the middle or inner ear directly. Therefore, these sounds that do not require the eardrum seemed much louder. Even after taking the protectors out, I find myself paying more attention to the sounds I make when I eat.