Classical
For the maximum signal power frame, 17.8537% of the signal remains.
For the 1/4th max signal power frame,12.3902% of the signal remains.
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| Project 3: Classical |
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| Click to hear Classical Sample | |||||||||||||||||||||||||||||||||||||||||||
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| 1. The input signal with a 2048 Hann window and 50% overlap (updated after trying 1/16th) and converted to spectral representation via DFT. | |||||||||||||||||||||||||||||||||||||||||||
| Click to see the Spectrogram | |||||||||||||||||||||||||||||||||||||||||||
| 2. Compute the 25 critical band Bark spectrum. | |||||||||||||||||||||||||||||||||||||||||||
| Click to see the Spectrogram | |||||||||||||||||||||||||||||||||||||||||||
| 3. Select two signal frames, one at the location of the maximum signal power, and the other at 1/4th the maximum power. Plot a) power spectrum, b) Bark spectrum, c) spread Bark spectrum, d) offset Bark spectrum, e) final threshold. | |||||||||||||||||||||||||||||||||||||||||||
| Click to see Question 3. a) - d) for Max Power | Click to see Question 3. a) - d) for 1/4th MAX Power | ||||||||||||||||||||||||||||||||||||||||||
| 4. Compute and plot the absolute threshold of hearing. | |||||||||||||||||||||||||||||||||||||||||||
| Click to see Question 3. e) and Question 4 for Max Power | |||||||||||||||||||||||||||||||||||||||||||
| Click to see Question 3. e) and Question 4 for 1/4th Max Power | |||||||||||||||||||||||||||||||||||||||||||
| 5. Determine the signal spectral components that remain audible after masking and falling below the threshold of hearing. For the maximum signal power frame, 17.8537% of the signal remains. For the 1/4th max signal power frame,12.3902% of the signal remains. |
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| 6. Reconstruct the time signal with the remaing audible power spectrum. | |||||||||||||||||||||||||||||||||||||||||||
| I had a difficult time doing this. I tried to follow the tips given to the class to aid in this process, but it wasn't able to successfully reconstruct the signal. Below is a link to the spectrogram I was able to produce (it is obvious the signal is not correct). Along with a sound file that compresses the audio sample with another codec that I didn't create. I am including this to provide an example of what my compressed signal should sound like and would be expected to sound like if I was able to successfully reconstruct the signal. | |||||||||||||||||||||||||||||||||||||||||||
| Click to see the Spectrogram | |||||||||||||||||||||||||||||||||||||||||||
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| Click to hear the compressed classical sample | |||||||||||||||||||||||||||||||||||||||||||
| The Matlab code used to create all of these graphs can be found below: | |||||||||||||||||||||||||||||||||||||||||||
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