Determine calibration factor for a microphone using a calibration sound source.

Author

Jan Benda

Options

• intensity=114dB SPL: Intensity of the sound source (number)
• frequency=1000Hz: Frequency of the sound source (number)
• intrace=Sound-1: Input trace (string)
• duration=1seconds: Duration of a single measurement (number)
• repeat=10: Number of measurements (integer)
• amplitude=0V: rms amplitude (number)
• amplitudestdev=0V: rms amplitude stdev (number)
• scale=0V/Pa: Scale factor (number)

Version

1.2 (Jul 30 2016)

Calibrating attenuation for loudspeakers.

Author

Jan Benda

Version

1.4 (Aug 3, 2017)

Calibrates attenuators such that a full amplitude sine wave is put out at an sound pressure level as requested by setIntensity(). The sound pressure level is based on the root mean square of the sound waveform!

Options

• frequencyrange=2000..20000..500: Frequency range (Hz) (string)
• intmin=45dB SPL: Minimum sound intensity (number)
• intrange=35dB SPL: Sound intensity range (number)
• intstep=5dB SPL: Sound intensity step (number)
• outtrace=Left-Speaker: Output trace (string)
• intrace=Sound-1: Input trace (string)
• reset=false: Reset calibration for each frequency? (boolean)
• clear=false: Clear calibration table? (boolean)
• duration=80ms: Duration of stimulus (number)
• skip=20ms: Initial time to skip for analysis (number)
• win=1ms: Window for computing rms response (number)
• fitslope=false: Fit slope in addition to offset (boolean)
• ramp=1ms: Ramp time of stimulus (number)
• pause=0ms: Pause between stimuli (number)
• scale=3.16: Scale for V/Pa (number)

Files

• calibspeakers-intensities.dat : the calibration data (measured versus requested stimulus intensity).
• calibspeakers-offsets.dat : the calibration data (measured versus requested stimulus intensity).

Plots

The plot shows the measured versus the requested stimulus intensity (red circles). The yellow line is a fit of a straight line to the data. This line should for a successful calibration coincide with the blue 1:1 line.

Requirements

• The LoadSpeaker Attenuate class associated with output trace Speaker-Left or Speaker-Right
• Microphone recording (e.g. a Sound-1 trace)

Check for echoes.

Author

Karin Fisch, Jan Benda

Version

1.2 (May 10, 2017)

Repeatedly play a signal with an triangular amplitude modulation and average the voltage output of a microphone. The averaged sound is then plotted as a function of distance the sound must have travelled. This way echos can be inspected.

Options

• duration=10ms: Stimulus duration (number)
• frequency=0kHz: Carrier frequency (number)
• intensity=80dB: Stimulus intensity (number)
• repeats=0: Repetitions of stimulus (integer)
• pause=100ms: Duration of pause between stimuli (number)
• outtrace=Left-Speaker: Output trace (string)
• intrace=Sound-1: Input trace (string)
• average=10: Number of trials to be averages (integer)
• maxecho=10m: Maximum echo distance (number)
• soundspeed=343m/s: Speed of sound (number)

Plot

The plot shows the averaged sound (orange) recorded by the microphone as a function of distance the sound must have travelled. The x-axis is shifted such that the peak of the triangular sound pulse indicates the distances. Without any delays the peak amplitude of the recorded sound will sit at distance zero (not the beginning of the sound pulse).

For orientation the original sound pulse is plotted in yellow at the position of the largest peak.

Converts intensities givenen in dB SPL to attenuation level in dependence on carrier frequency.

Author

Jan Benda

Version

1.4 (Jul 5, 2017)

Calibration

The conversion is set by the CalibSpeaker RePro which defines stimulus intensity as dB SPL, i.e. root-mean-square amplitude of a full-amplitude sine wave.

The calibration table is saved in the files calibD-C.dat where D is the device number of the data acquisition board and C is the analog output channel of that board.

Options

• line: the line on the attenuator
• aodevice: the identifier analog output device
• aochannel: the channel of the analog output device
• maxvoltage: maximum allowed peak voltage to be put out by the attenuator.

Measures sound level in dB SPL

Author

Jan Benda

Version

1.0 (Jul 28, 2016)

Options

• intrace=Sound-1: Input trace (string)
• origin=before end of data: Analysis window (string)
• offset=0ms: Offset of analysis window (number)
• duration=1000ms: Width of analysis window (number)
• scale=1.0: Scale for V/Pa (number)

Variables for standard output traces of acoustic stimuli and recordings from microphones.

Author

Jan Benda

Version

1.0