Sources

Key Signature Detection (FFT):

Here is a standalone script that demonstrates the FFT Method of the Key Signature Detection:

The results of this method on the files shown can be seen in this pdf file produced using MATLAB's Publish functionality:

Here are the clips of known key used to test the key signature detection functions:

Audio Files

75 songs were downloaded from the Free Music Archive: https://www.freemusicarchive.org/search

Credit to artists:

References

Beat Detection

E. Sheirer, “Tempo and beat analysis of acoustic musical signals,” The Journal of the Acoustical Society of America, 1998.

https://www.clear.rice.edu/elec301/Projects01/beat_sync/references.html

MFCC

Z. Qin, W. Liu, and T. Wan, “A Bag-of-Tones Model with MFCC Features for Musical Genre Classification,” Advanced Data Mining and Applications Lecture Notes in Computer Science, pp. 564–575, 2013.

Auditory Toolbox. https://engineering.purdue.edu/~malcolm/interval/1998-010/AuditoryToolboxTechReport.pdf

Wavelet Denoising

Wavelet Denoising Overview:

http://klapetek.cz/wdwt.html

http://klapetek.cz/wdenoise.html

Comparing Wavelet Types:

https://www.mathworks.com/help/wavelet/ug/wavelet-families-additional-discussion.html

https://www.researchgate.net/post/Can_anybody_compare_Haar_Daubechies_coiflet_and_symlet_wavelets

Matlab Webinars:

https://www.mathworks.com/videos/understanding-wavelets-part-3-an-example-application-of-the-discrete-wavelet-transform-121284.html

https://www.mathworks.com/videos/understanding-wavelets-part-2-types-of-wavelet-transforms-121281.html

Matlab Wavelet Toolbox:

https://www.mathworks.com/help/wavelet/ref/wavedec.html

https://www.mathworks.com/help/wavelet/ref/wdenoise.html

https://www.mathworks.com/help/wavelet/ref/waverec.html

https://www.mathworks.com/help/wavelet/ref/wthcoef.html

MATLAB Demo