What is this question doing under Electricity and Magnetisim? Sound is a mechanical phenomenon. It does not have to be produced by a speaker.
Perhaps you have in mind the 60Hz hum in consumer electronic equipment? It is caused by poor filtering of the power supply, or by coupling from the pre-filtered power supply to sensitive circuitry elsewhere in the device.
Sometimes, it is even caused by the motion of the power transformer windings. As they age, the glue holding them in place breaks down and they can actually make noise by their own mechanical vibrations, without relying on the speakers at all. The winding does undergo an actual mechanical force from the electromotive force (emf) of the current flowing in it.
But in a new, properly designed power transformer, that mechanical motion will be too small to make substantial noise.
There are many contributing factors to these differences. Partial deafness of the upper ranges can occur when the ear has been exposed to too loud of noised for long periods of time. Partial deafness can also be caused by old age (Teenagers typically hear the highest pitches of all people) and many other factors. The prime average age for the best hearing range is 10years old. The range of human hearing is generally accepted as 20hz to 20khz but just like people can have better than 20/20 vision, a few people (kids usually) in a thousand can hear up to 30khz.
A change of pitch in a sound is caused by a change of wavelength. This can be caused by a change in length or size of the vibrating or oscillating device or system causing the sound. When you press on a guitar string at one of the frets, for instance, you shorten the vibrating part of the string thereby shortening its wavelength and increasing its pitch - shorter wavelength = higher pitch.*
The pitch of a sound can also be changed by movement of the sound source away from or toward the listener. This is called Doppler effect. Moving away, the waves become stretched resulting in a lower pitch, and vice versa when moving toward the listener.
*Keep in mind that all sound waves travel at the same speed, so shorter wavelengths will reach your ears in greater numbers per second than longer wavelengths. This is called frequency. Higher frequency = higher pitch and, again, vice versa.
Adults can not hear high pitch sounds because when you are a kid you have microscopic hairs in your ears to hear high and low pitch sounds you have more low pitch than high pitch hairs and millions and millions of these hairs die every day by the time you get to an adult all of the tiny hairs die and no more grow.
other animals have hairs so they can hear even higher such as dogs or even lower such as dolphins and whales.
There are a few things that cause sounds to have higher pitches than others. One thing is simply the frequency.
High pitch = high frequency = short waves = comes from something moving fast
Low pitch = low frequency = long waves = comes from something moving slower
when underground elves sing that makes a higher pitch
bats can hear sounds of higher frequency than humans (supersonic) because they produce them and these sound waves echo back to them by bouncing of items so that they can see how far something is. Just like in submarines. therfore they need to 'hear' these 'supersonic' waves to see.
Celsius is the inventor of this scale, so it is correct. Centigrade is referring to the method of calculation. I guess some people hear "centigrade" often, so they use it. Hope this helped!
It depends very much on the sound pressure level the sound makes at the ears. Adults can often not hear sine tones higher than 15 kilohertz.
0 dB is the threshold of hearing. Some people can hear a very soft sound and some cannot hear anything.
People tend to like the first idea they hear and are hesitant to hear other ideas that clash with the first idea.
I heard that younger people can hear reallly high pitched noises but when you get older you cant anymore. deaf people cant hear anything
dogs can hear higher pitches. it doesn't "mean" anything. it is normal. dogs have better hearing.
High pitches are harder to hear than low pitches. However, with age, the ability to hear high pitches becomes even more difficult.
most animals like dogs can hear more higher pitches than us so they can hear it, you should not blow it too much, because it will hurt their ears.
...pitches that are higher (greater frequency of waves) than any one neuron is capable of transmitting.
Because as you get older, your ability to hear high pitches becomes worse. In theory, a child should be able to hear a maximum high pitch of 20,000Hz. This, however is only if the child's hearing is perfect. Animals of different kinds can hear different frequencies, usually a lot higher than a child or human of any age. When you are about 18, you can still hear a pretty high sound (unless your hearing isn't good), but from the second you are born, your hearing is all down hill...
to hear my recording on internet for others i put connect with the head phones to helpout
Schizophrenia is a chronic and disabling brain disorder. People with schizophrenia sometimes hear voices others don't hear, believe that others are broadcasting their thoughts to the world, or become convinced that others are plotting to harm them.
some people stare into space and can not hear others around them this is the fist sign,
It depends on you, and on what sort of learner you are. Some people remember more of what they see, and others what they hear or write down.
Jesus preached to large crowd of people in many places that were gathered outdoors.
The term "ultrasound" implies frequencies higher than what people can hear. That's higher than 20 kHz (20,000 Hz), since that's more or less the upper limit for a typical young person.