ISO 532-2-2017 pdf free.Acoustics一Methods for calculating loudness一Part 2:Moore-Glasberg method.
The method described in the main part of this document specifies a method for calculating loudness and loudness level based on the Moore-Glasberg procedure.
The procedure involves a sequence of stages. Each stage is described below. However, it is envisaged that those wishing to calculate loudness using this procedure will use the computer program (see Annex C) provided with this document that implements the described procedure. It is not expected that the procedure will be implemented by hand. Such computations would be very time consuming. The source code provided in Annex C gives an example of the implementation of the method. Other implementations using different software are possible.
NOTE 1 The computational procedure described In this document is an updated version of procedures published earlier elsewhereli.-i-iil.
NOTE 2 Uncertainties are addressed in Clause 9.
5 Specifications of signals
5.1 General
The spectrum of the signal whose loudness is to be determined shall be specified at each ear. The spectrum can be specified exactly using the methods described in £2. 53 and £4 for the case of a complex tone, noise consisting of bands of pink or white noise of defined width, or sounds having a mixture of discrete sinusoidal components or bands of pink or white noise. The sound spectrum can be specified approximately using one-third-octave-band levels specified in the method described in £5. For this, one-third-octave bands according to IEC 61260-1:2014 should be used. The methods described in £2 to £4 may be of interest for synthetic signals or signals analysed by discrete Fourier transform techniques. The method described in £5 will be usually used for practical signals. If the spectrum is specified exactly, the predicted loudness will be more accurate than when the spectrum is approximated using one-third-octave-band levels.
5.2 Complex tone
This is a sound with a spectrum that consists oiv discrete sinusoidal components. The spectrum can be specified in terms of frequency components that are either harmonically or non-harmonically spaced. The frequency and sound pressure level of each component shall be specified.
5.3 Noise consisting of bands of pink or white noise of defined width
The number of noise bands and their widths shall be specified. Each band can be composed of either filtered white noise (with a constant spectrum level within the passband) or filtered pink noise (with a spectrum level within the passband that decreases with increasing centre frequency at a rate of 3 dB/octave). For each band, the following shall be specified: the lower cut-off frequency, the upper cut-off frequency and the spectrum level. In the case of pink noise, the frequency at which the spectrum level is determined shall also be specified. Within the procedure, the spectra of bands of noise are approximated by a series of discrete sinusoidal components. When the bandwidth of the noise exceeds 30 Hz, the components are spaced at 10 Hz intervals, and the level of each component is set 10 dB higher than the spectrum level at the corresponding frequency. When the bandwidth of the noise is less than 30 Hz, the components are spaced at 1 Hz intervals, and the level of each component is set equal to the spectrum level at the corresponding frequency.
EXAMPLE I A band of white noise extending from 200 Hz to 500 Hz with a spectrum level of 50 dB would be approximated by sinusoidal components with frequencies 205 Hz, 215 Hz, 225 Hz, 235 Hz …. 475 Hz, 485 Hz, 495 Hz. each component having a sound pressure level of 60 dB.
EXAM PLE 2 A band of pink noise having lower and upper cut-off frequencies of 100 Hz and 115 Hz, respectively, with a spectrum level of 65 dB would be approximated by sinusoidal components with frequencies 101 Hz, 102 Hz. 103 Hz, 104 Hz …. 113 Hz, 114 Hz, 115 Hz, with the components having sound pressure levels increasing progressively from 64.7 dB at 101 Hz to 65,3 dB at 115 Hz.
NOTE The spacing of the components (10 Hz as in Example 1 or 1 Hz as in Example 2) is not a property of the input signal. The 1 Hz spacing is used to ensure sufficient accuracy in the computation of loudness when the bandwidth of the spectrum of the signal is narrow, i.e. less than 30 Hz. For signals with wider bandwidth, I.e. 30 Hz or greater, then a 10 Hz spacing will result in sufficient accuracy for the purpose of the computation of loudness.
5.4 Mixture of discrete sinusoidal components and bands of pink or white noise
For the case of mixtures of sounds, which each have a spectrum consisting of discrete sinusoidal components, 52 is applied for each discrete sinusoidal component that the mixed sound comprises. For the case of a mixture of bands of pink or white noise, the spectrum of each component of the mixture can be specified exactly using 5. This method is mainly applicable to synthetic signals, although it could be applicable to signals with strong line components in a noise background.ISO 532-2 pdf free download.