fbpx
May 18, 2021

Professional Tool Reviews for Pros


Understanding Sound Pressure Level and the Decibel Scale

Stihl BT 131 Earth Auger Review

Hearing protection is something we talk a lot about on any job. Hearing loss is one of those things that happens over time, so it’s not always a priority for younger guys and gals. But that scene of an old lady shouting at her husband just to be heard is only cute in movies and TV. It sucks in real life. With that in mind, we decided to put together a quick guide to understanding sound pressure level and the decibel scale (or dB scale).


What is Sound Pressure Level (SPL)?

Since we’re going for a functional level of understanding and not preparing you for a final exam, I’m going to skip some of the fine details and focus on the general concepts.

Sound pressure level, or SPL, is a measurement of sound pressure that uses Pascals (Pa) as its unit of measurement. We convert that into the more popular decibel scale, or dB scale.


Sound pressure is the difference between the pressure from a sound wave and the ambient pressure of what the sound is traveling through (usually air for our purposes).

The reason sound pressure levels and decibels are so important is that it gives us a numerical scale to work with to help prevent hearing loss.

Sound Pressure Level and the Decibel Scale

There are two major points to keep in mind when it comes to the dB scale: the actual sound pressure level and how loud something sounds

There are tons of decibel equivalent examples out there to give you a general idea of how loud something sounds at a certain decibel level like the one we’ve included.

Understanding Sound Pressure Level and the Decibel Scale - Decibel Levels

How Sound Pressure Level Works

When it comes to the sound pressure level (keeping in mind that sound pressure does the actual damage), it doubles every 3 decibels and has a magnitude of 10x every 10 decibels.

To put that into practice, let’s consider a conversation that registers 60 on the decibel scale (60 dB). A louder conversation at 63 decibels has 2x the sound pressure level, one at 66 decibels has 4x the SPL and a group of people talking to a level of 70 dB has 10x the SPL.

Change in Sound Pressure Level - Understanding Sound Pressure Level and the Decibel Scale

Compared to a 60 dB sound…

  • 63 dB has 2 times the SPL
  • 66 dB has 4 times the SPL
  • 69 dB has 8 times the SPL
  • 70 dB has 10 times the SPL
  • 72 dB has 12 times the SPL and so on…

How Perceived Loudness Works

When it comes to how loud something sounds, it’s a slightly different ballgame, but we can still understand it using the decibel scale. This one is a little more straightforward: as you move up 10 decibels, the noise sounds twice as loud.

Change in Perceived Loudness - Understanding Sound Pressure Level and the Decibel Scale

Compared to a 60 dB sound…

  • 70 dB sounds 2x as loud
  • 80 dB sounds 4x as loud
  • 90 dB sounds 8x as loud and so on…

How Sound Pressure Level and the Decibel Scale Affect Work

OSHA Table G-16 Permissible Noise Exposure - Understanding Sound Pressure Level and the Decibel ScaleOSHA defines how much noise you can be exposed to over specific periods of time. For example, you can work for 8 hours with your ears catching 90 decibels or you can work for 1 hour at 105 decibels. Both of those are limits per day.

Hearing protection lets us work longer in louder environments without violating those OSHA limits. When you’re shopping for hearing protection, look for the NRR value—Noise Reduction Rating. It very simply tells you how many decibels the device reduces.

If you’re working in an environment that’s a pretty constant 105 decibels and you use earmuffs with an NRR of 25, your ears are only exposed to 80 decibels. It’s pretty simple!

Related articles

How Steel Chainsaw Bars are Made – Stihl Factory Tour

If you’ve ever wondered how steel chainsaw guide bars are made, we’ve got you covered. What looks so simple actually involves a significant process of engineering and manufacturing. A recent visit to the Stihl Plant 2 in Waiblingen-Neustadt, Germany gave us an up-close-and-personal look at how they make these. Factory Overview About 80 people work […]

When to Fertilize Your Lawn

Knowing when to fertilize makes a big difference in how healthy your lawn stays throughout the year. Of course, every part of the country is different, so the tried and true timing we use in central Florida doesn’t work for everyone. Nor does the same fertilizer, for that matter. To get a broader scope, we […]

What is Plain-sawn or Rip-sawn Wood or Lumber?

Plain-sawn or rip-sawn wood uses a particular method of milling trees that yields highly usable, strong boards. It delivers the least amount of waste of any milling method. Unlike quarter sawn wood, particularly popular for oak and maple, plain-sawn wood presents less exposed grain on the face of the board. Most lumber uses this simpler […]

Rainwater Capture and Collection for Irrigation

It happens more frequently than you would think—a “normal” water shortage turns into a full-on drought. Now you’re stuck without enough water to take care of your landscape and preserve your plants. If you do water your plants, you do so illegally. That’s dangerous, self-serving, and (on a more practical note) sets you up to […]

Subscribe
Notify of
guest
1 Comment
Newest
Oldest Most Voted
Inline Feedbacks
View all comments
Brian Walker

This is the reason why I got custom earplugs from Big Ear. You never know when you’re gonna experience loud hearing damaging noises so you just have to be ready.

1
0
Would love your thoughts, please comment.x
()
x