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)