Chapter 5 was about sensation, and we discussed how noise and sound are processed in the body. Because we have a test on chapter five next Wednesday, I thought it would be interesting to refresh our memories about something.
Now that we know how sound is transduced: How can headphones "cancel" noise? How is it possible for certain headphones to block out all noises but the music?
Active noise canceling headphones very structures creates a barrier that blocks high frequency sound waves. They also actively erase lower-frequency sound waves. How? They create their own sound waves that mimic the incoming noise in every respect except one: the headphone's sound waves are 180 degrees out of phase with the intruding waves. (See above picture) The two waves- one coming from the headphones and one coming from the ambient noise- have the same amplitude and frequency, but their crests and troughs are arranged so that the crests of one wave line up with the troughs of the other wave and vica versa. The two waves cancel each other out, a phenomenon known as the destructive interference. In the end, we can listen to the sound we want to hear- the music!
Things for you to comment on so that you may actually comment:
1) Do you think that something like this, if developed further, might help people who are unable to focus on only one stimulus?
2) Did you realize that something that seems so easy is actually quite cool and miraculous?
3) Do you think that we really need to have noise cancelling headphones? Is it not enough for us to just listen to music and ignore the other stimuli?
4) We also said that after a stimulus keeps going and is not new, you tire of it and tune it out. Do you think that if you played a song on repeat for a while you would stop realizing you were listening to the music?
5) Have you ever fallen asleep while listening to music? Do you find it weird that we cannot remember the songs that were playing and aren't annoyed by the loud music pumping into our ears?
Suggestions for further research: How much do we damage our ears by putting loud music directly into them on a regular basis?
*I found out how noise cancelling works at electronics.howstuffworks.com.
2) Did you realize that something that seems so easy is actually quite cool and miraculous?
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Wow Zahava!I never realized that this related to what we learned in class!This is so intelligent!
I think it is good to have noise canceling headphones since I feel like they would not damage the ear as much since when you have normal earphones and there is a loud backround noise you will most likely turn it higher, sometimes too high which is not so good for the ear.
First of all, I think that everything, like hearing, seeing, smelling etc. is all very miraculous! So, this is as well! Questions 4 and 5 seem to relate to me most because I usually fall asleep listening to music, and sometimes i put on a certain playlist so the songs keep repeating throughout my sleep.I think that once we are asleep, we are no longer conscious that we are listening to the music, but it seems to be that we are unconsciously aware because i personally will notice that when I wake up, my ipod is often on the floor or halfway across my room! I think that I unconsciously get annoyed that the music is still playing, so i throw my ipod off my bed, but sometimes I wake up and my ipod is still there! Sometimes I will remember the song that was playing as I was falling asleep, and then I am not conscious of the rest. pretty cool!
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