Whether you’re a product designer, engineer, or manufacturer, chances are you’ve had to consider the effects of noise at some point in your career. And if you haven’t, you definitely should! Excessive noise can not only be annoying, but it can also lead to hearing loss, cardiovascular problems, and even death. That’s why it’s so important to ensure that your products are properly tested for noise before they hit the market.
Anitech noise testing is a comprehensive guide to everything you need to know about noise testing. We’ll cover everything from what noise is and how it’s measured to the different types of noise tests and how to interpret the results. By the end of this guide, you’ll have a better understanding of how to reduce the risk of noise-related problems in your products.
What is Noise?
Noise is unwanted sound. It can be either external (e.g., traffic noise) or internal (e.g., machinery noise). Noise can also be either audible (e.g., music) or inaudible (e.g., ultrasound). The effects of noise depend on both the intensity and duration of exposure.
Intensity is measured in decibels (dB), while duration is typically measured in hours. The louder the sound, the higher the dB level; however, even low-level noise can be harmful if it lasts for a long time. For example, exposure to 90 dB noise for more than 8 hours per day can cause hearing loss.
There are two main types of hearing loss: sensorineural and conductive. Sensorineural hearing loss is caused by damage to the inner ear or auditory nerve, while conductive hearing loss is caused by damage to the outer or middle ear. Both types of hearing loss are permanent and cannot be reversed.
How is Noise Measured?
Noise is measured with a sound level meter (SLM), which assigns a numeric value to the loudness of a sound based on how sensitive our ears are to different frequencies of sound waves. The SLM has two parts:
a microphone that picks up sound waves and converts them into electrical signals, and
an amplifier that increases the strength of these signals so they can be read by the SLM’s display unit.
How Are Noise Test Results Interpreted?
The results of SPL, SIT, OLT, and SLT tests are all expressed in terms of decibels (dB). The higher the dB level, the louder the sound. For example, a SPL test result of 80 dB means that the sound pressure exerted by the sound waves on a surface is 80% as intense as the reference level—the lowest level at which human ears can detect sound—which is 0 dB SPL. Similarly, an SIT test result of 80 dB means that the amount of energy carried by the sound waves is 80% as intense as 0 dB SIT—the lowest level at which human ears can detect sound when there is no background noise present. An OLT test result of 80 dB means that human listeners perceive the sound as being 80% as loud as 0 dB OLT—the quietest possible sound that human ears can hear—while an SLT test result of 8 out 10 means that listeners rate the sound as being 8 times louder than 0 dB SLT—the softest possiblesound that human ears can detect 50%of time under optimal listening conditions.
Noise testing is an important way to ensure that your products are safe for use and will not cause harm to people who use them. There are four main types of noise tests—sound pressure level tests,sound intensity tests objective loudness tests ,and subjective loudness tests —and each type measures something different about noise levels . SPL, SIT , OLT ,and SLT results are all expressed in terms of decibels , with higher numbers indicating louder noises . Be sure to keep this guide handy next time you need t o interpret th e results o f a noise test!