MOUNTING GP-CIRCUIT BREAKER 7C2206 - Caterpillar

in all directions from the hole or edge. Because of this, screens and barriers must be very large in order to be effective against low frequency sounds.
High frequency sound is highly directional. High frequency sound is easy to reflect. High frequency sound is often produced by sources which radiate a high noise level in some directions but low levels in other directions. High frequency sound can be reflected from a hard surface in the same way that light is reflected from a mirror. High frequency sound will pass through a hole like a beam of light. It will not spread out from the hole like a low frequency sound will. High frequencies will not diffuse around edges, so barriers are effective against them.
When you are close to the source, high frequency noise is more annoying than low frequency noise. Since the human ear is more sensitive to high frequencies than low frequencies, a low frequency must be louder than a high frequency in order to be as annoying. Sometimes, reducing the frequency of a nearby sound can reduce the annoyance, even if the sound is as loud as ever.
When you are far from the source, low frequency noise is more annoying than high frequency noise. High frequency sound are more absorbed by the air over long distances than low frequencies. This is because absorption is dependent on the number of cycles, and there are more cycles in high frequency sound than in low frequency sound. It is also easier to shield a high frequency sound wave. If noise in the immediate area of the sound is not an issue,shifting the sound to a higher frequency may help. The sound could be absorbed by the time it reaches the hearer.
Sound travels long distances in a structure. Vibration that is inside a structure can travel a very long distance due to low internal damping of the structure. This is especially true of homogeneous structures like concrete and steel. The energy does not reduce, and as soon as a large surface is attached to the vibration, the large surface acts like a loudspeaker. This creates much noise. The best way to prevent this type of noise is to isolate the body from the vibration. Isolate as close to the source as possible.
Vibration that is inside of a structure needs a large area to convert into sound that travels through the air. When small objects vibrate, they do not usually produce much sound. This is because the small surface are of the object that is vibrating does not set many air particles in motion. However, if you connect a large panel to the source of vibration, more sound will be created, since more air particles will be set in motion. This is the same effect that was discussed in Step 6. For example, a tuning fork makes almost no noise until the fork is connected to a sounding board. Another example is a boiler furnace. The pump causes the pipework to vibrate,