Decibel Meters: Exploring Sound Level Measurement Devices and Their Applications
Sound can enhance our lives. Things like our favorite music and the speech of loved ones can help lower blood pressure and relieve stress. But when sounds become too loud, we cross from pleasant to painful, and the effects can be life long. Ensuring the sounds we’re routinely exposed to are kept at safe levels is important for both our physical and emotional wellbeing.
Utilizing a sound level measuring device like a decibel detector or meter can show us exactly where our noise exposure stands. In the workplace, they can let us know if the sound levels are safe over an 8 hour shift. In pro audio, we use them to dial in acoustics and get great sound. They’re a fairly simple machine with big benefits.
What is a decibel meter?
A decibel meter is a type of sound level measuring device that allows us to know the exact volume of noise exists in any particular environment. Very simply, they measure sound pressure and show us via an analog or digital readout exactly how loud the space is.
With the help of a few features, these sound level detection devices provide a simple way to see the strength of the sounds we’re exposed to in our workplaces, outdoor environments, and everywhere in between. There are a few different types to choose from, and the right one depends on usage.
Meter Classes or Types
Sound meters are currently offered in two main classes, and they are differentiated primarily by their accuracy. Class 1 meters are more accurate than class 2 meters, so are preferred whenever incredible accuracy is required. They do come with a higher price tag, however.
Class 2 meters are much cheaper than Class 1, so they are perfect for general purpose noise monitoring. They are accurate enough for many situations, but where safety or litigation are of concern, then a Class 1 is likely your better option.
If a meter is labeled Type 1 or Type 2, that’s not exactly the same thing as Class 1 or Class 2. It simply means they are compliant with an older standard. Anything listed as either Class 1 or 2 is compliant with the most recent standard. Older monitors may be labeled with a Type numbered 0 to 3. Here’s what each type represents:
- Type 0 – Laboratory Meters (most accurate)
- Type 1 – Precision Grade (more accurate)
- Type 2 – Industrial Grade (less accurate)
- Type 3 – Survey Meters (least accurate)
Features
Most decibel meters and other sound level measuring devices also have some features that help us get the readouts we’re after without too much confusion. Most meters will offer both frequency weighting and time weighting. Here’s what each of those mean.
Frequency Weighting
Weighting involves weighting the output to represent the results slightly differently for individual needs. You’ll typically see A, C, and Z frequency weighting. The readings with an ‘A’ weighting reflect how human ears interpret sounds in the 20HZ to 20kHz frequency range.‘C’ weighting also reflects the human ear, but deals with much higher noise levels. And lastly, ‘Z’ weighting represents all frequencies equally. When it comes to protecting workers’ hearing, most countries mandate that ‘A’ weighting be used in assessments.
Time Weighting
Most sound level measuring devices also utilize time weighting. It’s intended to damp sudden level changes, which creates a smoother display that may be easier to read. If the level fluctuates readily and rapidly, slow (S) time weighting will prevent the output from jumping all over the place. If the level stays fairly consistent, the fast (F) option may work better in that case. Additionally, some meters have impulse (I) settings. These are most commonly used in situations where we are measuring sharp banging noises like those that accompany fireworks or gunshots.
How are sound intensity measurements displayed?
Sound is measured in what are known as decibels. More specifically, decibels measure sound intensity and amplitude. Understanding decibel readings is fairly simple. The higher the number, the louder the sound. Unfortunately, the more we are exposed to sounds on the higher end of the spectrum, the more likely we are to suffer from emotional distress and some kind of hearing damage as a result.
Most decibel charts go from zero to about 140. In these scales, zero is a perceived complete absence of sound, and 140 is equivalent to fireworks or a jet engine. Each increment of ten decibels is ten times more powerful than the increment in front of it. That means that 20 decibels is ten times more powerful than 10 decibels. 30 decibels is ten times more powerful than 20 decibels and 100 times more powerful than 10 decibels. This pattern follows all the way to the top. You can see how we get from complete silence to a jet engine in just 140 ticks. Your sound level measuring device may or may not cover the entire spectrum, so your needs will determine which meter is right for you.
How sound affects us: some facts about noise pollution and exposure
Prolonged exposure to quiet sounds is generally considered safe. This includes all sounds that fall under the 70 decibel threshold, when measured by a sound level measuring device. It’s not painful and won’t cause hearing problems with chronic exposure. However, as sounds become louder and louder, we can suffer hearing damage quickly.
OSHA, or the Occupational Safety and Health Administration, requires hearing protection in any environment with a sustained noise level of 85 decibels or higher. This is about the noise level produced by a hair dryer, vacuum cleaner, or a noisy restaurant. Studies have shown that exposure to these sounds for 8 hours or longer is very likely to cause hearing damage, which is the reason behind the OSHA standards for noise levels.
The extent to which sound can affect our hearing depends on 3 main factors, which are decibel level, distance from the source, and the amount of time we are exposed. According to the National Institute of Health, noises are more likely to damage your hearing when the following criteria are met.
- 85 dBA(A-weighted decibels) – a few hours exposure time
- 100 dBA – 14 minutes or longer exposure time
- 110 dBA – 2 minutes or longer exposure time
As you can see, louder sounds are capable of damaging our hearing much more quickly than softer ones. If you are going to be in an extremely loud environment for an extended period of time, it’s best to put as much distance between yourself and the source of sound as possible. Also, wearing earplugs is a great way to reduce your exposure, when there is little chance of avoiding it.
Where sound level measuring devices are used
There are a lot of places where we would be wise to use a sound level measuring device to assess the risk to our hearing, but there are industries and groups who routinely use instruments for measuring noise level. The reasons range from reducing noise pollution to making that noise pollution sound perfect.
The Workplace
One of the most common places people are exposed to overly loud noises is at work. Whether you work in transportation, use power tools in your job, or work in a warehouse with loud machines grinding on all day, you will likely be exposed to dangerous noise levels for a good part of the day. It’s important to mitigate that exposure for both your physical and mental health. In fact, it’s the law.
OSHA requires any business that averages 85 decibels of noise exposure over an 8 hour shift or 8 hour time-weighted average to implement a hearing conservation program. A good noise monitor will alert you to any violations before they become a bigger problem.
Musicians
Many musicians find that their ability to hear clearly diminishes over time. This is due to chronic exposure of sounds well over 85 decibels. If they play regular shows with a band, they can easily be exposed to sounds over 100dB, which can damage hearing fairly quickly. If you are in a band, consider wearing earplugs to your gigs. It’s not the most rock ‘n’ roll thing you can do, but protecting your hearing for the long haul is a great insurance plan for working musicians.
Music venues and recording studios
These places rely on great sound to get their business done, so they often use sound level measuring devices to perfectly dial in the acoustics in the room. It’s the easiest way to discern measurable differences and dictate the perfect placement of acoustical materials and seating areas. Understanding where acoustical issues are present is a key solution of sound pollution.
FAQ
Which federal legislation sets standards for maximum noise levels?
Many current regulations are based on the Noise Control Act of 1972, which gives the EPA (Environmental Protection Agency) the authority to establish noise control regulations.
How do I reduce indoor noise levels?
One thing you can do to reduce indoor noise levels is to introduce absorptive materials into the space. This will allow sound waves to become trapped, reducing the occurrence of reverberation. As sound waves bounce back and forth off of hard surfaces, they become amplified and make the ambient noise in the room louder. Absorptive materials like acoustic panels and foam trap some of those sound waves, keeping the overall volume down.
How do I learn more about different models?
Working with a reputable dealer is the best way to get the complete specs on any sound level measuring device before purchasing. Check with someone who offers sound monitoring devices at different levels. They will understand the needs of their customers and provide an effective solution for everyone.
