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Owning Palette: Sound Quality VIs

Requires: Sound and Vibration Measurement Suite

Computes stationary loudness from the sound pressure signal waveform or the 1/3-octave band spectrum calculated over the frequency range 25 Hz to 12.5 kHz. Wire data to the sound pressure signal [Pa] input to determine the polymorphic instance to use or manually select the instance.

Because stationary loudness measurements use linear averaging, stationary loudness is most applicable to steady-state noises or signals that do not vary with time. Stationary loudness is also known as ISO 532B loudness and Zwicker loudness.

Details  Example

Use the pull-down menu to select an instance of this VI.

Select an instance SV Stationary Loudness (Time) (1 Ch)SV Stationary Loudness (Octave) (1 Ch)

SV Stationary Loudness (Time) (1 Ch)

	diffuse field specifies if the sound field is diffuse (TRUE) or a free field (FALSE). The default is free field (FALSE).
	sound pressure signal [Pa] specifies the sound pressure signal in Pascals. This signal keeps track of the timing of the waveform and the values the waveform contains. t0 specifies the start time of the waveform. dt specifies the time interval in seconds between data points in the waveform. Y specifies the data values of the waveform.
	error in (no error) describes error conditions that occur before this node runs. This input provides standard error in functionality.
	specific loudness returns the specific loudness at the critical band rate. The critical band rate is in units of bark. A bark is the unit of measurement for critical band rate. A bark, a pure tone represented as a masking curve, produces a plot consistent with frequency and more accurately than linear or logarithmic plots. The bark scale ranges from 1 to 24, resulting in 24 barks, or cumulative critical bands, from 0 to 16 kHz. You can wire this output to the specific loudness input of the Loudness instance of the SV Aures Sharpness VI.
	loudness [Sone] returns the perceived loudness in units of sones. The sone scale produces a linear scale of loudness. A sone is the unit of measurement for loudness between two or more sound signals. This measures the perceived loudness of a sound in terms of decibels and frequency. One sone equals 40 dB at 1 kHz, the loudness of a 1 kHz sound with a sound level of 40 dB, or 40 phons.
	loudness level [Phon] returns the perceived loudness level in units of phons. Phons compensate for the effect of the frequency on the perceived loudness level of the tones. A phon is the unit of measurement for loudness on a scale corresponding to the decibel scale of sound pressure level, with the number of phons of a given sound being equal to the decibels of a pure 1 kHz sine tone judged by the average listener to be equal in loudness to the given sound. At 1 kHz, sound signal readings are the same in phons and in decibels.
	loudness info returns information about the loudness measurement. You can wire this output to the loudness info input of the Loudness instance of the SV Aures Sharpness VI. x-axis units returns the units of the x-axis. 0 Frequency—The number of occurrences of a repeating event during a period. 1 Critical band—The smallest band of frequencies around a given frequency. 2 Critical band rate—The frequency scale used in describing characteristics of the human hearing system. x-axis unit label returns the label of the x-axis. y-axis units returns the units of the y-axis. 0 Band power 1 Level 2 Loudness 3 Sharpness 4 Roughness 5 Fluctuation strength 6 Tonality y-axis unit label returns the label of the y-axis. data attributes returns information about the sound quality measurements this VI analyzes.
	error out contains error information. This output provides standard error out functionality.

SV Stationary Loudness (Octave) (1 Ch)

	diffuse field specifies if the sound field is diffuse (TRUE) or a free field (FALSE). The default is free field (FALSE).
	octave spectrum specifies the octave spectrum to perform the operation on, in band power versus nominal frequencies. nominal frequencies [Hz] specifies the nominal, or preferred, frequencies as opposed to the exact frequencies associated with each 1/n octave band. band power specifies the band power in decibels associated with each 1/n octave band.
	octave info specifies information about the octave spectrum that you can pass from another VI. Note  You must wire octave info when performing extended measurements. Do not modify the octave info values. If you want to view the information, you can right-click the octave info wire and select Custom Probe»Octave Info from the shortcut menu.
	error in (no error) describes error conditions that occur before this node runs. This input provides standard error in functionality.
	specific loudness returns the specific loudness at the critical band rate. The critical band rate is in units of bark. A bark is the unit of measurement for critical band rate. A bark, a pure tone represented as a masking curve, produces a plot consistent with frequency and more accurately than linear or logarithmic plots. The bark scale ranges from 1 to 24, resulting in 24 barks, or cumulative critical bands, from 0 to 16 kHz. You can wire this output to the specific loudness input of the Loudness instance of the SV Aures Sharpness VI.
	loudness [Sone] returns the perceived loudness in units of sones. The sone scale produces a linear scale of loudness. A sone is the unit of measurement for loudness between two or more sound signals. This measures the perceived loudness of a sound in terms of decibels and frequency. One sone equals 40 dB at 1 kHz, the loudness of a 1 kHz sound with a sound level of 40 dB, or 40 phons.
	loudness level [Phon] returns the perceived loudness level in units of phons. Phons compensate for the effect of the frequency on the perceived loudness level of the tones. A phon is the unit of measurement for loudness on a scale corresponding to the decibel scale of sound pressure level, with the number of phons of a given sound being equal to the decibels of a pure 1 kHz sine tone judged by the average listener to be equal in loudness to the given sound. At 1 kHz, sound signal readings are the same in phons and in decibels.
	loudness info returns information about the loudness measurement. You can wire this output to the loudness info input of the Loudness instance of the SV Aures Sharpness VI. x-axis units returns the units of the x-axis. 0 Frequency—The number of occurrences of a repeating event during a period. 1 Critical band—The smallest band of frequencies around a given frequency. 2 Critical band rate—The frequency scale used in describing characteristics of the human hearing system. x-axis unit label returns the label of the x-axis. y-axis units returns the units of the y-axis. 0 Band power 1 Level 2 Loudness 3 Sharpness 4 Roughness 5 Fluctuation strength 6 Tonality y-axis unit label returns the label of the y-axis. data attributes returns information about the sound quality measurements this VI analyzes.
	error out contains error information. This output provides standard error out functionality.

SV Stationary Loudness Details

The SV Stationary Loudness VI measures the 1/3 octave spectrum, combines the fractional-octave bands into critical bands, and then applies spectral masking. The VI returns the result as the specific loudness versus critical band rate, and then integrates the specific loudness to measure the total loudness and loudness level. This VI calculates the stationary loudness in compliance with ISO 532B, DIN 45631, and other standards.

Example

Refer to the SVXMPL_Stationary Loudness and Sharpness (Simulated) VI in the labview\examples\Sound and Vibration\Sound Quality directory for an example of using the SV Stationary Loudness VI.