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 .
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This measurement describes the subjective loudness.
Therefore, dB A is very limited in its usage although widely used. This approximation is only valid in the far-field with spherical radiation. Therefore, we strongly recommend documenting this different measurement distance clearly, because it is difficult to compare different measurement distances.
As mentioned previously, sone is valid for stationary signals only. A complete measurement system for sone contains the following components:. Sound can be described with various physical parameters e.
Loudness measurement in sone (DIN 45631 ISO 532B)
A pure sine at lower levels e. A result was a model for the human hearing.
For stationary signals you will achieve much better results than the traditional dB A. A famous psychoacoustics effect is acoustical masking. We strongly recommend switching off noise sources if possible windows, air-condition, computers etc.
Loudness measurement in sone (DIN ISO B)
Program for calculating loudness according to DIN (ISO B)
A sound level of 82dB will be displayed as 94dB. In contrast to dB A sone is a linear parameter.
In addition, you have to calibrate the system. This can be achieved with a sound calibrator or a sound pressure meter. If you use a sound level calibrator with 94dB, the reference level has to set to 82dB. Nobody would expect to hear the sound of a mouse during a symphonic orchestra, although the mouse would audible in quiet phases. In the near-field you will encounter e. In most sound pressure meters available today you will find these techniques, because they are easily to derive from the physical parameters.
This increases the signal level by 12dB. A very famous application of this and other effects are audio compression techniques like MP3. Only parts of the signal, which are audible according to a model, are stored. The reference level is one sone, which is equivalent to a tone with 1kHz at a level of 40dB. Simply switch off the measurement device. These parameters are very limited to describe the perception of the human ear.
A first approach is to take into account that the ear is less sensitive at lower and higher frequencies. Loudness Sone A wideband noise has a different subjective loudness than a pure tone at the same level measured in dB A. The research work around from Barkhausen result into the well known A,B,C weighting curves. In a normal office environment at a quiet noise level of 45dBA it is impossible to analyze a fan with 25dBA.
For complex sounds and noise, this simple model is not valid anymore. We will explain this with an example. A complete measurement system for sone contains the following components: Two sone has double loudness compared to one sone.
Many sone measurements include analysis of low noise devices e. You can improve the measurement sensitivity by reducing the measurement distance from 1m to e. Many measurement microphones have a sensitivity of 30dB, which defines the lower bound for measurements. For every measurement, we strongly recommend to measure the quiet noise first.
However, it does not allow distinguishing between nice or annoying tones. The optimum measurement environment is a special anechoic chamber, which reduces reflections and noise from outside. A wideband noise has a different subjective loudness than a pure tone at the same level measured in dB A.
Based on its countless hearing tests, Zwicker developed a model for loudness measured in sone. 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.
Zwicker analyzed various psychoacoustics effects thoroughly. By reducing the distance to the half, the level increases by 6dB. You can only perform a reliable measurement if the signal level is above the noise.
This offset can be corrected with a different calibration factor, which allows WinAudioMLS to dn the measurements results with respect to 1m. Since the human ear is very sensitive, such measurements require high quality measurement equipment. The noise includes acoustic noise from the environment and noise in the measurement chain from the microphone or preamplifier. The normal measurement distance is 1m.