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These questions are concerned MRI hardware and quality control of images.

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Acoustic Noise Levels

Answer this...

But just how loud is that? Compare with something I can relate to.

Decibel LevelExample
30Quiet library, soft whispers
40Living room, refrigerator, bedroom away from traffic
50Light traffic, normal conversation, quiet office
60Air conditioner at 20 feet, sewing machine
70Vacuum cleaner, hair dryer, noisy restaurant
80Average city traffic, garbage disposals, alarm clock at two feet
 (The following noises can be dangerous under constant exposure)
90Subway, motorcycle, truck traffic, lawn mower
100Garbage truck, chain saw, pneumatic drill
120Rock band concert in front of speakers, thunderclap
140Gunshot blast, jet plane
180Rocket launching pad

The time-to-damage (hearing loss) of a particular noise level depends on frequency as well as amplitude. High frequencies tend to be more responsible for hearing loss than low frequencies. Some interesting reading may be found at the Deafness Research Foundation, the source of the above data. The threshold above which sounds can cause instantaneous acoustic trauma is 140 dB.

Further reading on this topic:
Online: IMRSER

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