Adventures In Audio

What is the difference between 0 dB and 0 dBFS?

by David Mellor
LEARN AUDIO ONLINE ► FREE TRIAL ►

If you use a digital audio workstation, then you will come across the concepts of 0 dB and 0 dBFS a hundred times a day. Clearly you need to understand what they mean...

There are a number of ways of measuring signal or sound levels in decibels. In this article I will describe the difference between dB and dBFS.

By the way, when I say 'sound' I mean an audible sound traveling in air. A signal is a representation of that sound in either electronic or digital form.

Differences in signal or sound levels are measured in decibels (dB). So a measurement of 10 dB means that one signal or sound is 10 decibels louder than another, or that a signal or sound has been made 10 decibels louder than it was before.

0 dB

The Audio Masterclass Music Production and Sound Engineering Course

FREE TRIAL

Ready to take your recording to the next level? Take a 30-day FREE TRIAL of the Audio Masterclass Music Production and Sound Engineering Course - Our most popular course.

It is important to note that these sounds could be quiet, medium or loud. Decibels, in their dB form, do not describe the absolute level of a signal or sound, only any comparison or change in level.

0 dB therefore means no difference in level, or no change in level.

A common error

It is a common error to say that, for instance, the sound level of a helicopter from a distance of 50 meters is 100 dB. What is usually meant is that the sound is 100 dB louder than the quietest sound the average human ear can hear but the person quoting the measurement doesn't understand this important detail.

The level of the helicopter is 100 dB SPL (standing for Sound Pressure Level), where 0 dB SPL is the reference level. You can think of 0 dB SPL as the sound made by a dead leaf hitting the ground in the fall. You can just hear it, but anything quieter would be imperceptible.

dB SPL relates only to actual sound, not to signals.

0 dBFS

The Audio Masterclass Music Production and Sound Engineering Course

FREE TRIAL

Ready to take your recording to the next level? Take a 30-day FREE TRIAL of the Audio Masterclass Music Production and Sound Engineering Course - Our most popular course.

'FS' stands for 'Full Scale' and 0 dBFS is the highest signal level achievable in a digital audio WAV file. Higher levels are possible inside digital audio workstation software, but in the files that are recorded on disk, 0 dBFS is the highest level.

All other levels can be measured and described with respect to 0 dBFS. So for example a signal that is 10 decibels lower than the maximum possible level is -10 dBFS. A signal inside the digital audio workstation could be +10 dBFS, but it would need to be lowered in level for output as a WAV file, otherwise it would be clipped, meaning that the tips of the waveform would be squared off at 0 dBFS.

Summary

Decibels are used to describe differences or changes in level. 0 dB means 'no change'.

Values in dBFS are used to describe signal levels in comparison with the highest level a WAV file can handle.

Saturday July 14, 2018

The Audio Masterclass Music Production and Sound Engineering Course

FREE TRIAL

Ready to take your recording to the next level? Take a 30-day FREE TRIAL of the Audio Masterclass Music Production and Sound Engineering Course - Our most popular course.

Like, follow, and comment on this article at Facebook, Twitter, Reddit, Instagram or the social network of your choice.

David Mellor

David Mellor

David Mellor is CEO and Course Director of Audio Masterclass. David has designed courses in audio education and training since 1986 and is the publisher and principal writer of Adventures In Audio.

More from Adventures In Audio...

Graphic equalizer demonstration using the Waves GEQ Classic

Harmonic enhancement: In the master or individual tracks? (Can you hear the difference?)

What will happen if your snare drum clips?

EQ demonstration HF bell boost

How much bass can a Bluetooth speaker produce?

One weird trick for monitoring your mix on a Bluetooth speaker

Can a preamp's pad work as a pop filter

Get the sound you want from the tools you have

What is the phase button for on a microphone preamplifier?

Choosing studio monitors - Is it your most important buying decision?

What is a channel strip? Why should you use one?

Audio effects explained - A quick guide for beginners

How to choose the best key for your song

The amazing stereo effect that no-one can hear

What is the best studio microphone?

Bad Audio Diary BAD 9: What's wrong with this picture?

Weird and wonderful sounds using the Air Music Tech Chorus plug-in

The end of latency?

An investigation of the pre-delay parameter of the Lexicon 480L reverb plug-in

Add reverb to your recordings using the natural echo chamber technique

Why you should ventilate your home recording studio

Q: What is your main concern if your interest is voice over?

Why do microphones sound different?

Channel strips - powerful tool or utter folly?