While Decibel (dB) is used to indicate sound levels, very few musicians actually understand the concept of decibels. You’ll hear this term quite often when using amps, electronic devices, and audio software.
Highlights
- While dB numbers typically measure sound levels, it’s also used to measure voltage and power of audio gear/equipment.
- Decibel numbers are logarithmic and not LINEAR. With logarithmic numbers, each additional unit increases the true value exponentially. For example:
+3dB = 2 times the power
+10dB = 10 times the power
+60dB = 1,000,000 times the power - In music, decibels are a measurement of Sound Pressure Level (SPL).
Decibels & Perceived Loudness & Distance
Without going into the calculations, here’s a simple rule that most sound engineers/musicians follow (these are not exact, but almost correct):
- +10dB = 2x the loudness
- +20dB = 4x the loudness
- +40dB = 16x the loudness
Another thing, the farther you go away from the sound source, the mellower the sound gets. But ‘By How Much’?
Without going into the maths, here are rules of thumb that musicians follow (to keep things simple):
- 2X the distance = -6dB
- 10X the distance = -20dB
Decibel Explained
Though you may have guessed that it is used to indicate sound levels, it is actually used for a wide variety of measurements in acoustics, electronics, signals, and communication.
In our case, you’ll find it used to measure:
- Gains of amplifiers
- Attenuation of signals
- Signal-to-noise ratios
These are often expressed in decibels.
It helps to understand this concept, as you’ll come across this term in all probability while working with compressors and amplifiers.
Here’s a video showing how decibel is used in audio software.
Real-Life Examples of Decibel Levels
Here’s an easy way to get a feel for decibels…by listening to real life noises of course. Here are some examples that you would already be familiar with, and the decibels associated with it:
- Breathing sounds: 10 dB, Whispering: 20 dB
- Normal conversation: 40 dB
- Background noise at a restaurant: 60 dB
- Listening to radio or watching TV: 70 dB
- Garbage disposal: 80 dB
- Jack hammer: 100 dB
- Threshold of pain: 130 dB
- Jet engine: 150 dB
I hope you get an idea now.
Why is It Used?
You probably don’t have to go into the details of this, but one important advantage of Decibel (DB) is that it is very convenient to represent very large or small numbers, and also carry out simple calculations using it.
In case you are using consecutive amps, calculating the overall gain is easy as you just have to add up the decibel gains of the individual components.
Remember that Decibel is not a LINEAR measurement (not like 2 pounds is twice as 1 pound). Decibels are LOGARITHMIC units of measurement.
Here’s a useful resource explaining more of Decibel (DB)
Another good video explaining the concepts of Decibel (DB)
Decibels in Your Recording Studio
In your recording studio, you see decibels with level meters. Top of a level meter indicates 0 dBFS (meaning 0dB full scale), the highest possible signal level the equipment can accommodate before clipping or distorting.
So you’re supposed to keep the dB level below that. Most musicians aim for anywhere between -15dB and -6dB when setting input levels for recording (-10dB should be good to start with).
KeytarHQ editorial team includes musicians who write and review products for pianists, keyboardists, guitarists & other musicians. KeytarHQ is the best online resource for information on keyboards, pianos, synths, keytars, guitars and music gear for musicians of all abilities, ages and interests.
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