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Owning Palette: Sound Quality VIs

Installed With: Sound and Vibration Measurement Suite

Computes time-varying loudness of the sound pressure signal from a time-varying 1/3 octave band spectrum.

This VI measures the 1/3 octave spectrum using exponential averaging with a 2 ms time constant, combines the fractional-octave bands into critical bands, and applies temporal and spectral masking. The VI returns the result as the specific loudness versus critical band rate, and then integrates the specific loudness and applies temporal post-masking filters to measure the time-varying loudness. National Instruments recommends running the SV Time-Varying Loudness VI within a data acquisition loop because the VI processes successive 1/3 octave spectra of 2 ms blocks of sound pressure data.

This VI calculates the time-varying loudness in compliance with DIN 45631.

	reset specifies if the VI post-masking temporal filters need to be reset (TRUE) or not reset (FALSE). The default is FALSE. The filters are automatically reset the first time this VI runs.
	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. t0 is the start time of the waveform. dt is the time interval in seconds between data points in the waveform. Y contains the data values of the waveform.
	error in describes error conditions that occur before this VI or function runs. The default is no error. If an error occurred before this VI or function runs, the VI or function passes the error in value to error out. This VI or function runs normally only if no error occurred before this VI or function runs. If an error occurs while this VI or function runs, it runs normally and sets its own error status in error out. Use the Simple Error Handler or General Error Handler VIs to display the description of the error code. Use exception control to treat what is normally an error as no error or to treat a warning as an error. Use error in and error out to check errors and to specify execution order by wiring error out from one node to error in of the next node. status is TRUE (X) if an error occurred before this VI or function ran or FALSE (checkmark) to indicate a warning or that no error occurred before this VI or function ran. The default is FALSE. code is the error or warning code. The default is 0. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code. source specifies the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning. The default is an empty string.
	specific loudness [Sones/Bark] returns the specific loudness at the critical band rate. The critical band rate is in units of bark.
	time-varying loudness [Sones] returns the time-varying loudness from a 1/3 octave spectrum. t0 is the trigger time of the waveform. dt is the time interval in seconds between data points in the waveform. Y is the data values of the waveform.
	offset and multipliers identifies the amount the waveform shifted. t0 is the minimum value of the time segment expressed in seconds. delta t is the time increment expressed in seconds. y0 is the minimum value of the critical band rate in units of bark. delta y is the increment of the critical band rate in units of bark.
	loudness info returns information about the loudness measurement. x-axis units returns the units of the x-axis. The valid values are Frequency, Critical Band, and Critical Band Rate. x-axis unit label returns the label of the x-axis. y-axis units returns the units of the y-axis. The valid values are Band Power, Level, Loudness, Sharpness, Roughness, Fluctuation Strength, and 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. If error in indicates that an error occurred before this VI or function ran, error out contains the same error information. Otherwise, it describes the error status that this VI or function produces. Right-click the error out front panel indicator and select Explain Error from the shortcut menu for more information about the error. status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred. code is the error or warning code. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code. source describes the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning.