What is the decibel?

The decibel (dB) is a unit used to measure loudness in audio engineering and music production. Originally developed as a logarithmic unit for the amplification of electrical signals, it is now also used to measure sound intensity in acoustics.

An increase of 10 dB roughly corresponds to a doubling of the sound intensity or the perceived loudness. The human ear can perceive sound intensities from 0 dB (complete silence) to around 130 dB (very loud sound, such as when an airplane takes off). Exposure to sound intensities above 85 dB can cause irreparable damage to the ears.

What is a decibel scale?

In the decibel scale, the value of sound intensity or loudness is given in relation to a reference value. This reference value was set as the minimum sound intensity that the human ear can perceive (0 dB). The decibel scale is therefore a logarithmic scale as it represents changes in sound intensity or loudness relative to a reference value.

How Accurate are Decibel Apps?

The accuracy of decibel apps depends on various factors such as the quality of the microphone, the accuracy of the hardware, the calibration of the app and the environmental conditions. Typically, however, decibel apps are not as accurate as professional sound level meters used by acoustic engineers and other professionals such as the audio engineer at the Mixing or mastering should be used.

Still, decibel apps can be useful in many cases to get a rough idea of ​​the sound intensity or loudness in an environment. For example, they can be used to measure the volume of music or noise in the environment, or to determine whether a certain place is loud or quiet. However, it is important to note that the accuracy of decibel apps can vary and they are not equally well suited to all applications.

What are the decibel units?

There are also other units used for more specific applications. This includes:

  • Bel: A unit used to measure the gain of electrical signals. 1 Bel corresponds to an amplification of 10 dB.

  • Neper: A unit used to measure gains in electromagnetic fields and optics. 1 Neper corresponds to a gain of 20 dB.

  • Phon: A unit used to measure the intensity of sound in human hearing. It is often used to indicate the loudness of music or sounds that are audible to the human ear.

  • dB FS:

    "dB FS" stands for "decibels relative to full scale" and is often used in relation to digital audio signals. It refers to the possible dynamic range of a digital audio signal encoded in a specific format.

    The term full scale (FS) refers to the maximum amplitude that a digital audio signal can have. When a signal is specified in dB FS, the amplitude of the signal is expressed in terms of that maximum amplitude. A signal with a value of 0 dB FS thus has the maximum amplitude possible, while a signal with a value of -6 dB FS has half the maximum amplitude. The term dB FS is often used in relation to digital audio signals to indicate how loud or quiet the signal is compared to its maximum amplitude. It is also used to assess the quality of audio recording and playback devices and to ensure that the audio signal is not distorted during playback.

  • dB(A): "dB(A)" stands for "decibel a-weighted" and refers to a type of sound level measurement used to indicate loudness in human hearing. It is commonly used to measure the loudness of ambient noise or music. The a-weighting was developed to better represent the sensitivity of human hearing. The human ear is more sensitive to certain frequencies than others, and a-weighting accounts for these differences by giving more weight to certain frequencies. The dB(A) unit is commonly used to measure sound intensities that are audible to the human ear. Long-term exposure to sound intensities above 85 dB(A) can damage the ears. It is important to note that the a-weight is not suitable for all applications and that there are other weights that can be used for more specific applications, such as the c-weight or the z-weight. It is important to note that the different units are not comparable and are applied differently depending on the application.

  • dB (C): It is often used to measure the loudness of very high or very low frequencies, which are less sensitive to the human ear than other frequencies.

  • db LU: Unlike other weights such as A-weight or C-weight, the linear unit does not take into account the sensitivity of human hearing to specific frequencies. Instead, sound intensity is measured directly in relation to the amplitude of the sound.