Fourier Analysis of a .aiff file

Question

I'm trying to use Mathematica to perform Fourier Analyses on sound files, but I'm not sure how to get the Frequency Spectrum from the .aif file.

The instructions I have say:

1. use Mathematica’s Play command to take data samples of the tone at 11,025 samples per second.

2. use Mathematica’s Export command to convert the data into a .aif file.

3. use GarageBand to alter the sound wave data with one of 15 effects.

4. use Mathematica’s Import, Fullform, and Table commands to convert the new .aif file into 11,025 data samples.

5. use Mathematica’s Fourier and ListLinePlot commands to generate and plot the frequency spectrum of the altered sound wave data.

Therefore, I first produced a pure tone of 1 second by writing Play[Sin[2 Pi 440 t], {t, 0, 1}], naming it 'test' and exporting it with Export["test.aiff", test]

Where I get stuck is converting the .aif file back to the data points by using Fullform and Table commands, and converting the Fourier Transform into a Frequency Spectrum using the ListLinePlot.

If anyone could help it would be greatly appreciated, thank you in advance

Answer 1

If you're just trying to get the data itself, you can try:

test = Play[Sin[2 Pi 440 t], {t, 0, 1}]
Export["test.aiff", test]
audio = Import["test.aiff"]
data = AudioData[audio][[1]]

This will also work for a single step:

data = Import["test.aiff", "Data"]