with Anchor Audio

What is a decibel, anyway?


Decibel (dB) is a measurement used constantly in the audio industry - just check out all of our product pages, tech specs, you name it! They’re not just empty numbers, we are actually trying to tell you something about the sound intensity and loudness of our sound systems! So, what the heck is a decibel, anyway?

Straight of the Merriam Webster Dictionary, a decibel is defined as:

 1.   a : a unit for expressing the ratio of two amounts of electric or acoustic signal power equal to 10 times the common logarithm of this ratio 

      b : a unit for expressing the ratio of the magnitudes of two electric voltages or currents or analogous acoustic quantities equal to 20 times the common logarithm of the voltage or current ratio 

2: a unit for expressing the relative intensity of sounds on a scale from zero for the average least perceptible sound to about 130 for the average pain level 

3: degree of loudness; also: extremely loud sound — usually used in plural


For our purposes, we’re going to focus on definition 2 and how we use it to measure the loudness of our sound systems. 


How is sound measured? 

A decibel is a unit for expressing Sound Pressure Level (SPL), or the relative intensity of a sound. How loud something seems is actually subjective, depending on the person listening; however, the energy output of the source is objective and very measurable. If you don’t want to calculate this by hand (see definition 1a, yikes), a sound pressure level (SPL) meter measures sound levels by calculating the pressure of the sound waves traveling through the air from a source of noise. 


How Anchor Audio does it:

The SPL is measured in decibels. Our sound system’s SPL measurement result from a combination of:

1. Microphone sensitivity

2. Mixer pre-amp voltage

3. Main amplifier wattage

4. Speaker efficiency. 

Amplification Process


Here are some common sounds we can relate to and their associated SPL.


Decibel chart

It’s hard to imagine complete silence at 0 db, rustling leaves at 20 dB, then a close-range power mower at 107 dB.  Seems like that escalated quickly, and it did! The decibel scale is a logarithmic scale as opposed to linear, which means that every 10 dB increase is 10x as intense and roughly twice as loud.


When we say the Bigfoot is the most powerful sound system on the market, designed to cover a football field, we’re not joking! Albeit, the decibels are measured at the industry standard at 1 meter (~3.3 ft.), but you should never be that close to the system at full volume. No really, please don’t! This thing can put out some serious power!


The next time you’re shopping for your new sound system and see the dB rating listed, ask yourself: do I want the equivalent of normal conversation or a jet plane? Decisions, decisions…