03-19-2012 01:06 AM
I want to use a function SV Time-Varying Loudness in the Sound and vibration suite. The output of this function is exactly what I require for my speech analysis.
I have a speech sample recorded from the microphone obviously a voltage signal. This function requires a sound pressure signal.
The voltage signal would be proportional to the sound pressure signal right? How do I convert this voltage signal to the sound pressure signal (Pa).
I'm not even sure if I can use this function. I trying to extract the features from the speech signal. The algorithms used for this are linear predictive coding , perceptual linear predictive coding and mel frequency cepstral coefficients.
I already implemented Linear predictive coding in labVIEW. I wanted to try out Perceptual linear predictive coding because it is considered to be robust in noisy conditions.
This SV time varying loudness function does the exact thing I want to do but I don't know if it is applicable to speech signals.
In the help I says this VI process 2ms blocks of sound pressure data. But speech signals are to be processed only at 10 to 15ms. Please help
03-19-2012 02:30 AM - edited 03-19-2012 02:37 AM
Your microphone should have calibration tables to relate the output voltage to an audio quantity like dB or perhaps even Pa.
Mike...
03-19-2012 03:04 AM
The microphone specification which relates the voltage and the pressure level is given as:
Sensitivity: -51±5dB @ 1kHz 0dB=1V/Pa
How am I supposed to proceed with this?
03-19-2012 03:10 AM
The sensitivity is -51 dbV/Pa, that is 2.82 mV/Pa
Cheers
Edgar
03-19-2012 04:26 AM
Why is specified as @1kHz? Does it vary for different fequencies? Or is it just the center frequency ?
03-19-2012 05:48 AM
This is the specification the manufacturer chose. Which way it varies depends on the specific microphone. You can either ask the manufacturer for more data or calibrate it by yourself, either with a well known reference sound source or by comparison with a well known reference microphone.
Cheers
Edgar