In my music theory class, my teacher said that all sound is the result of vibrations. Any time something vibrates, it creates a sound wave. But I have two questions about that.
1. If that is so, then what is vibrating in electronic devices that makes sound (computers, iPods, TVs, etc.)
2. Why is it that when I shake any object really fast, it doesn't make a sound... for example if I shake my hand as fast as I can, wouldn't it be vibrating, therefore make a sound? But it doesn't...
Idk if this is relevant, but my teacher also said that most sounds aren't pure, meaning that most acoustic sounds actually have many different pitches in them. For example, if I strum a guitar string, there are actually a ton of different tones being played at once, but when they are put together, it sounds like one singer note. However, digital sound IS a pure note. For example, an electric guitar tuner would make a pure note. Again, idk if that is relevant to my questions, but it sounds like it could be...
So thanks in advance! =)
1. If that is so, then what is vibrating in electronic devices that makes sound (computers, iPods, TVs, etc.)
2. Why is it that when I shake any object really fast, it doesn't make a sound... for example if I shake my hand as fast as I can, wouldn't it be vibrating, therefore make a sound? But it doesn't...
Idk if this is relevant, but my teacher also said that most sounds aren't pure, meaning that most acoustic sounds actually have many different pitches in them. For example, if I strum a guitar string, there are actually a ton of different tones being played at once, but when they are put together, it sounds like one singer note. However, digital sound IS a pure note. For example, an electric guitar tuner would make a pure note. Again, idk if that is relevant to my questions, but it sounds like it could be...
So thanks in advance! =)
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Your music teacher is correct in all these statements. Anything that vibrates in air does produce sound. (Sound cannot travel in a vacuum.) But when something vibrates in air or other media, it causes the surrounding molecules to move back and forth, and this is sound.
Computers, I-pods, TV's, radios, etc contain loudspeakers, often very small ones, similar to the speakers in a pair of earphones or ear buds.
As far as shaking your hand. you ARE producing sound, but the frequency is too low for you to hear, though an elephant standing nearby probably would hear it! (Elephants communicate over distances of many miles by using infrasonics - sounds which are too low for us to hear!) A young person with "normal" hearing can hear frequencies between about 20 and 20,000 Hertz, (Cycles per second). As we age, we tend to lose our sensitivity to higher frequencies. Your teacher is also correct in saying that a guitar string makes many different frequencies. Listening to very loud music or other loud sounds destroys high frequency hearing, so when you hear a car's stereo a block away, the driver is KILLING their high frequency hearing!!! This is why people working in high-noise environments, such as around jet planes, are required to wear hearing protection!
Computers, I-pods, TV's, radios, etc contain loudspeakers, often very small ones, similar to the speakers in a pair of earphones or ear buds.
As far as shaking your hand. you ARE producing sound, but the frequency is too low for you to hear, though an elephant standing nearby probably would hear it! (Elephants communicate over distances of many miles by using infrasonics - sounds which are too low for us to hear!) A young person with "normal" hearing can hear frequencies between about 20 and 20,000 Hertz, (Cycles per second). As we age, we tend to lose our sensitivity to higher frequencies. Your teacher is also correct in saying that a guitar string makes many different frequencies. Listening to very loud music or other loud sounds destroys high frequency hearing, so when you hear a car's stereo a block away, the driver is KILLING their high frequency hearing!!! This is why people working in high-noise environments, such as around jet planes, are required to wear hearing protection!
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