Problem of removing noise from an audio signal using filters

Problem of removing noise from an audio signal using filters on matlab. I am not actually sure how i would go at solving this problem right here so any help or advice would be appreacited. Also if you want to see the .mat files I could send them to you, I just didnt see any way of doing it here on chegg.

I posted pictures of the frequency plots to look at:

The first plot is the bad signal that i am trying to filter and the second one is the good signal to compare it to

100 E 50 O) 0 € Int\" -50 1000 2000 3000 4000 5000 6000 7000 8000 Frequency (Hz) x 10 9 -5 O 10 -15 1000 2000 3000 4000 5000 6000 7000 8000 Frequency (Hz)

Solution

In the question, it is mentioned that the most of audio energy is concentrated at lower frequency. You can plot the power spectral density Plot(10*log10(FFT(magnitude))) of the given sampled input. It will have power across the entire frequency spectrum, but should be concentrated primarily in the lower frequencies. Figure out a cut-off point that will preserve most of your \"signal(audio signal)\" but should also get rid of most of your noise.