Find the most up-to-date version of DIN at Engineering Calculation of loudness level and loudness from the sound spectrum – Zwicker method – Amendment 1: Calculation of the loudness of time-variant sound. DIN /A Calculation of loudness level and loudness from the sound spectrum – Zwicker method – Amendment 1: Calculation of the loudness of .
|Published (Last):||3 August 2015|
|PDF File Size:||20.67 Mb|
|ePub File Size:||2.35 Mb|
|Price:||Free* [*Free Regsitration Required]|
A complete measurement system for sone contains the following components:. In contrast to dB A sone is a linear parameter. Most people will agree that the sound of a flute is much nicer than a drill used by dentist although they both might have the same loudness.
We strongly recommend switching off noise sources if possible windows, air-condition, computers etc. If you use a sound level calibrator with 94dB, the reference level has to set to 82dB. Loudness Sone A wideband noise has a different subjective loudness than a pure tone at the same level measured in dB A. Therefore, dn A is very limited in its usage although widely used.
ISO B / DIN Loudness
Since the human ear is very sensitive, such measurements require high quality measurement equipment. It is ideally in the judgment of air conditioners or typical PC noise like hard disks of fans. Therefore, we strongly recommend documenting this different measurement distance clearly, because it is difficult to compare different measurement distances.
In most sound pressure meters available today you will find these techniques, because they are easily to derive from the physical parameters. We will explain this with an example. However, in practice sine tones are not very common. Many sone measurements include analysis of low noise devices e. With a distance of 25cm the correction factor is 12dB.
For every measurement, we strongly recommend to measure the quiet noise first. Zwicker analyzed various psychoacoustics effects thoroughly. This offset can be corrected with a different calibration factor, which allows WinAudioMLS to show the measurements results with respect to 1m. The reference level is one sone, which is equivalent to a tone with 1kHz at a level of 40dB. Only parts of the signal, which are audible according to a model, are stored.
The noise includes acoustic noise from the environment and noise in the measurement chain from the microphone or preamplifier. Nobody would expect to hear the sound of a mouse during a symphonic orchestra, although the mouse would audible in quiet phases.
As mentioned previously, sone is valid for stationary signals only. This measurement describes the subjective loudness. The frequency response of the ear depends fin the sound level, that is the reason for different curves, which are valid for a certain level only. Sound can be described with various physical parameters e.
This can be achieved with a sound calibrator or 456311 sound pressure meter. For stationary signals you will achieve much better results than the traditional dB A.
A famous psychoacoustics effect is acoustical masking. You can improve the measurement sensitivity by reducing the measurement distance from 1m to e. A sound level of 82dB will be displayed as 94dB. In the near-field you will encounter e. Many measurement microphones have a sensitivity of 30dB, which defines the lower bound for measurements. However, it does not allow distinguishing between nice or annoying tones. A pure sine at lower levels e. The research work around from Barkhausen result into the well known A,B,C weighting curves.
All psycho acoustic analysis requires absolute sound levels. A very famous application of this and other effects are audio compression techniques like MP3. In addition, you have to calibrate the system.
ISO 532 B / DIN 45631 Loudness
In a normal office environment at a quiet noise level of 45dBA it is impossible to analyze a fan with 25dBA. Based on its countless hearing tests, Zwicker developed a model for loudness measured in sone.
You can only perform a reliable measurement if the signal level is above the noise. The optimum measurement environment is a special anechoic chamber, which reduces reflections and noise from outside. This increases the signal level by 12dB. This approximation is only valid in the far-field with spherical radiation.
Simply switch off the measurement device. For complex sounds and noise, this simple model is not valid anymore. Two dun has double loudness compared to one sone. A complete measurement system for sone contains the following components: By reducing the distance to the half, the level increases by 6dB.
Loudness measurement in sone (DIN 45631 ISO 532B)
The normal measurement distance is 1m. A result was a model for the human hearing. A loud tone hides quiet tones.
A wideband noise has a different subjective loudness than a pure tone at the same level measured in dB A.