# What is something that is really loud

## Decibels - what is actually loud?

The volume is given in decibels (dB). That is true, but it is expressed very imprecisely and actually only half the story. When it comes to describing the perception of volume, it becomes a lot more complicated.

### Why we use decibels at all

What we perceive auditory, are changes in air or sound pressure. That is why the term is often used in connection with volume Sound pressure level - and the sound pressure is measured in the unit Pascal. Why do we now find decibel values ​​instead of Pascals in the audio sector?

The fact that the relationships with volume information are a little more complicated is due to human hearing. The perceptible changes in sound pressure are in a range between 0.00002 Pascal and 20 Pascal. The range therefore extends over several orders of magnitude (number of digits in numbers). If the sound pressure level is low, we can already perceive small changes in air pressure; at higher levels, on the other hand, the changes in air pressure must be significantly greater in order to be perceptible.

A linear scale would not really make sense to represent this because differences would not be visible at low values. That's why decibels are called logarithmic auxiliary unit used. With a logarithmic scale, the values ​​are increased tenfold at defined intervals. So there is a zero added to every value on the scale. If you visualize this in a curve, it does not rise constantly, but becomes increasingly steeper as it progresses.

### The decibel table: sound events and their dB values

In order to be able to correctly classify volume information in decibels, one must know that a doubling of the dB value does not mean a doubling of the sound pressure level. A chainsaw with a volume of 120 dB generates a sound pressure that is many times higher than an average loud conversation with 60 dB. A doubling occurs with an increase from 50 to 60 decibels. The pain threshold for the human hearing is reached at a volume of 120 dB. We then inevitably cover our ears and hearing damage can occur after a short time.

This table shows different sound events and the corresponding decibel value:

Sound eventdB
calm breathing10
light wind, whisper30
Speaking volume60
vacuum cleaner70
Car engine from a short distance90
Loudly turned up headphones95
Circular saw, loud music system100
chainsaw120
Jet plane from a short distance140

#### Note on dBFS

In the hi-fi sector it is more common for amplifiers to show negative dB values. This is usually the unit dBFS (decibels relative to full scale). This scale is used in digital signal processing. The zero corresponds to the highest achievable value; accordingly, other values ​​are displayed in the minus range.

### What also defines the perception of volume

You can dive much deeper into the matter. Because the pure sound pressure level does not take into account an important property of the human hearing when perceiving volume. How intensely a certain sound pressure is perceived depends on the pitch or frequency of the sound. In order to come close to the perceived volume of a sound, frequency-dependent weighting filters were introduced for decibels. These are sometimes given in brackets: dB (A). There are also psychoacoustic units like Phon and Sonethat also take into account the frequency-dependent auditory impression.

Basically, volume is only limited quantifiablebecause the perception is very different from person to person. While a neatly cranked up system with 95 decibels seems just right for one, that can be far too much for the other. In addition, even one and the same person can perceive volume very differently depending on their constitution. For example, stress has a great influence on perception.

### Decibels that your ears love

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### The most important things summarized in decibels

• Decibel is an auxiliary unit of measurement for specifying sound pressure.
• As a logarithmic scale, the dB scale is suitable for representing the sound pressure range that can be heard by humans.
• At 120 dB, the sound pressure reaches a level that we find uncomfortable or even painful.
• The perceived volume always depends on the reproduced frequency.
• So-called weighting filters and psychoacoustic variables such as sone and phon have been introduced to take the frequency into account when specifying volume.