Data Returned By Audio Read ?

Hello all, I have a question in regards to audioread function in matlab (might be easy to some of you). Audioread('wave.wav') will return a normalized data of -1 to 1. So what exactly is this data type ? example if you measure vibration through use of vibration sensor, the data you can be be m/s (speed of vibration) etc or if you measure temperature using temperature sensor, you will get degree cel etc so if you use audioread on a wav file what is the data type (units) ?? It is sound pressure ?

[KSSV]

audioread reads the .wav / sound file and returns sampled data, y, and a sample rate for that data, Fs. How you can have a sound/ audio file from vibration sensor and temperature sensor?

[crixus]

yes I understand that it returns sampled data, what I'm not sure is what is the unit for that sampled data. Vibration and temperature sensor are just examples i used to illustrate what I'm talking/asking about

[KSSV]

If vibration and temperature are not audio files then using audioread is ruled out.

[crixus]

i guess you dont understand my question ....

Answer 1

[Jan]

The wav file contains the audio signal after the AD sampling. Then it means xVolt, where x is an an scaling factor, which depends on different values and does not matter for the processing. The value represents the amplitude of the sound, when recorded by the microphone, therefore it is actually a pressure.

[crixus]

the pressure you are referring to is air pressure ?

[Jan]

@crixus: If the microphon records the sound under water, it is the water pressure. Somebody calculated the sound of the big bang, see https://www.mathworks.com/matlabcentral/answers/57446-faq-how-can-i-process-a-sequence-of-files, than it is the pressure realted to the density fluctations in the matter distributed of the universe.

[crixus]

alright. thanks for your input, appreciate it.

[Kayla Magee]

Where the output is xVolt, is the 'voltage' a peak to peak voltage? What is the specific amplitude? i.e. peak to peak, peak, rms, etc. ?? Thanks!