What is SPL? Great Guide to Understanding Sound Pressure Levels! (2023)

What is SPL?


Many people see the shortened variation of sound pressure level on their manuals for microphones, headphones, speakers, and whatnot – but do not understand what this specification means. Well, now in the era of abbreviations, it is easy to be confused.

Here in this article, we will try to explain what exactly is an SPL and how it may be to your benefit knowing that this measurement is. Let’s start!

So What is SPL?

SPL or sound pressure level is a measurement of sound pressure. Whereas it natively uses Pascals (Pa) as a unit of measurement, we use gadgets that mechanically convert that into the extra commonly-used decibel (dB) scale.

However what is sound pressure level? SPL measures the distinction between the pressure from a sound wave vs the pressure of what it’s traveling by. For the most part, we’re speaking about air and we assume 0 atmospheres (despite the fact that that’s not fairly correct).

Why are we talking about sound pressure levels and decibels? Well, for one, they provide us with the very numerical scale we use when referring to how loud one thing is. Taking that information we will do some wonderful things, like calculating methods to stop hearing loss.

For instance, we now have a whole lot of testing information and science that lets us know what ranges of sound pressure may be sustained safely over varying intervals of time.

What is dB SPL and Decibels

The sound pressure level is measured relative to the auditory limit. Which means 0 dB SPL is the brink of hearing. Anything beneath 0 dB SPL is inaudible. An instance of places with unfavorable dB SPL are anechoic chambers. These particular rooms are designed to soak up all sound and acoustic reflections, and they’re used to check everything from headphones to fighter jets.

A decibel is a unit of measure that makes use of the logarithmic scale. What’s that imply? Well, a rise of 10 dB means the sound intensity is multiplied by 10 to the +1 energy. For instance, 20 dB is 10 times louder than 10 dB, and 70 dB is 1,000,000 times louder than 10 dB. Each addition or subtraction of 10 dB provides or subtracts an additional zero to the multiplier. Decibels are used all over the place within the scientific community, not only for measuring sound.

Remember the fact that SPL can be dependent on the distance from the supply. For example, a jet engine at 3 ft produces a vastly larger SPL than one at 300 ft.

How is SPL Measured?

It’s measured with a Sound Pressure Level Meter, and there are many units out there, no matter if they are hardware or applications for smartphones. Sound enters the meter via the microphone, after which the meter evaluates the sound values by changing them into electrical data and the measurement values in decibels are shown.

An SPL Meter is usually handheld, mobile, and lightweight, and is manufactured in line with worldwide requirement standards. There is a range of SPL meters of high quality in keeping with these requirements.

The meters will rapidly take measurements of noise level and permit the consumer to determine sources or conditions where noise could be a difficulty both for occupational (noise at work) causes, for environmental pollution, or for loud sounds in our neighborhood.

SPL Meter

A-Weighted vs C-Weighted dB SPL

You might notice different weightings when it comes to measuring SPL. That simply means we’re utilizing an A-weighted SPL reading. It has to do with how the sound pressure level meter information sounds at varied frequencies. So let’s check the differences now.

A Weighting – dBA SPL

By far, A-weighting is the most typical kind of measurement utilized in recording audio levels in terms of noise. Much like the human ear, A-weighting rounds off each lower and higher frequency that common folks simply can’t hear.

Your specific A-weighted sound pressure level is measured by designating dBA or dB(A) SPL.

C Weighting – dBC SPL

The explanation for C-weighting is to more precisely reproduce how the human ear hears at increased output levels (like 100 dB SPL) where we are inclined to experience a lot of flatter responses.

Most SPL meters include both A-weighted and C-weighted modes (in addition to quick and slow response modes to get extra of an average SPL vs instantaneous reading). You sometimes see that C-weighting is used when measuring bass frequencies.

dba vs dbc - What is SPL

Audio Units and the Max SPL

A microphone is an electroacoustical system that converts the sound pressure within the air into an electrical signal. Microphones are used for both measuring SPL and, as everyone knows, recording and transmitting audio. Microphones vary in their operation. As an illustration, condenser microphones pick up on a change in capacitance, whereas ribbon microphones measure the speed of the internal parts.

A speaker can be an electroacoustical system, but it surely converts electricity to sound. A speaker is principally a microphone working in reverse.

A widespread specification you’ll see on a microphone, speaker, and different audio gear data sheets is a max SPL. That is simply the most sound pressure level in dB that the microphone or speaker can deal with without producing an unacceptable level of distortion. Unacceptable is outlined as higher than 0.5% THD.

Mics with excessive max SPL ratings are nice for recording percussion and different very loud sources generally. Speakers with high max SPLs are perfect for massive venues where lengthy distance coverage is required.


We believe that now this topic is a little bit clearer than before. It is really good to understand everything that is shown on the manuals of your units, and this is one other measurement that is good to know and use when setting your speakers in your room, your usage of microphones for recordings, and how hard you can push your headphones before blowing your ears.

In case you are having any other questions in regard to the topic of SPL, please let us know in the comment section below and we will be more than happy to assist!


Nikoloski is the founder and main content writer and editor of Mixing Tips. With his experience in audio engineering, mixing, and mastering for over 15 years, will provide hands-on experience and expertise in all the matters covered on this website.

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