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Feedback Comments on Sound

by Ron Kurtus

A total of 189 comments and questions have been sent in. They are listed according to date.

List of next 10 letters




Sound Waves Why can't you hear waves from a pendulum? Pakistan
Sound Waves What is wave? Pakistan
Sound Frequencies and Wavelengths Is ultrasound be harmful to the human ear? India
Noise Cancellation Can noise cancellation stop tinnitus? USA
Sound Waves I can't find the mini-quiz USA
Sound Waves Define sound terms USA
Doppler Effect for Sound Equations Doppler Effect when both source and observer are moving Nigeria
Sound Beats Is beat frequency AM? Iran
Noise Cancellation How to dampen the noise from a blender USA
Sound Amplified Over Water Calm water adds to sound amplification USA

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First 10 letters

Why can't you hear waves from a pendulum?

Topic: Sound Waves


June 11, 2013

Why the waves produced by a simple pendulum not heard?

irfan - Pakistan



A pendulum does create sound waves in air, but the frequency is well below what a person can hear. A pendulum that is powered, such that it vibrates extremely fast can create sound waves a person could hear.

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What is wave?

Topic: Sound Waves


June 11, 2013

What is wave?

irfan - Pakistan



A wave is a disturbance, oscillation, or vibration, either of a medium and moving through that medium. A water wave is a good example.

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Is ultrasound be harmful to the human ear?

Topic: Sound Frequencies and Wavelengths


May 19, 2013

Will ultrasound be harmful to human ear?

Nandini - India



I could be harmful if the volume or amplitude is high enough. Ultrasound provides more energy than normal sound frequencies, but its amplitude is usually not that high.

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Can noise cancellation stop tinnitus?

Topic: Noise Cancellation


April 26, 2013

With this technology,I wonder if it would be possible for people with tinnitus if a type of hearing aid could be developed that could cancel the ringing. I think you could determine the db frequency of the ringing simply by taking a hearing test. I don't know if this would help you hear any better but at least it would stop that ringing. Millions of people have this problem. Me included.

Wayne - USA



although it is an interesting idea of trying to use noise cancellation to stop a person's tinnitus, I don't think it would work. Tinnitus is the perception of sound caused in your hearing circuitry. There is really no way--that I know of--to determine the perceived frequency and waveform. Even then, providing a sound at the correct frequencies would probably have no effect on the tinnitus.

Tinnitus is related to Meniere Disease. A couple of other good resources are: Ringing in the Ears and Tinnitus.

I hope that helps. Best wishes in getting relief. I also have occasional tinnitus and know how annoying it can be.

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I can't find the mini-quiz

Topic: Sound Waves


April 24, 2013

I can't find the mini-quiz.




There should be a Mini-Quiz tab near the top of the page. Click the tab to get to the quiz.

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Define sound terms

Topic: Sound Waves


April 15, 2013

Your presentations were crystal clear and it was amazing. But there was one tiny problem though, it was a bit difficult for me to understand. I read in Class 6 so please define the following things in easy language:
1. wavelength
2. frequency
3. intensity

I appreciate your help and please do hurry about emailing me. I need it by 2 hours. IT'S AN EMERGENCY!!!

Thanks in advance.

Rosella ^-^

Rosella - USA



Wavelength is the distance between crests of a wave. Think of the distance between peaks or a water wave for example.

Frequency is how often crests of a wave goes past a given point in a second.

Intensity of a wave is the same as amplitude. With sound, it is like loudness.

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Doppler Effect when both source and observer are moving

Topic: Doppler Effect for Sound Equations


April 7, 2013

I found this convincing explanation very helping. But in doppler effect, you do not talk about the situation where by both the observer and the source are moving toward or away from each other. Any information about that? Thanks alot.

Ishaq - Nigeria



See the "General frequency equation" section in Derivation of Doppler Effect Frequency Equations for the equation of the change in frequency. Note that "c" represents the velocity of the wavefront, whether it is sound or light.

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Is beat frequency AM?

Topic: Sound Beats


February 26, 2013

When We Add Two sinusoidal waves together result is "Beat".
Why the Beats of sinusoidal waves aren't AM modulation?
can You explain?

haem - Iran



When the sinusoidal waves have frequencies close to each other, you can detect the beat frequency. Although this is a simple form of amplitude modulation (AM), which is used in Am radio is variation of signal strength that is independent of the frequency.

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How to dampen the noise from a blender

Topic: Noise Cancellation


January 18, 2013

Is there anything available or in the works to dampen the sound of kitchen appliances? I have a blender that makes a racket when grinding ice. If there is such a thing where could I go to get information and is it cost effective?

Bruce - USA



I know that blenders can be very noisy. The dog runs out of the room when my wife is using the device.

Unfortunately, there really isn't anything available to cancel or reduce the noise from a blender. Manufacturers could add noise reduction material, but it would increase the size of the device and make it more expensive. So they opted to avoid the issue.

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Calm water adds to sound amplification

Topic: Sound Amplified Over Water


November 15, 2012

Although I can not argue with your physics, wouldn't calm water have a greater affect on the ability of sound to travel over water rather than the temperature? My assumption is that sound waves bounce over smooth water much like sound travels better on would vs. carpeted floors.

Mark - USA



That is a good point that calm water would allow sound water to reflect off the surface better than choppy water. So it is an added factor in making the sound seem amplified.

I'll add that factor to the page.

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