title: How to remove the noise from a wav file with a IIR Eliptical filter
body: <p>I have to remove the noise from a wav music file with matlab.</p>
  
  <p>I know that I have to use the <code>ellipord</code> and <code>ellip</code> functions. First I read the wav file:<code>[x,Fs]=wavread('file.wav');</code> </p>
  
  <p>Then I do a spectrogram: 
  <code>spectrogram(x,512,400,512,Fs,'yaxis');</code></p>
  
  <p><img src="https://i.stack.imgur.com/EsPaK.png" alt="enter image description here"></p>
  
  <p>Now, I can't understand some things:</p>
  
  <ul>
  <li>I have to remove that red line? (I suppose that's the noise)</li>
  <li>What is the Wp value on the ellipord function? (I know it calls passband corner frequency).</li>
  <li>The Ws value will be something like between 14000 and 16000 hz? It's value to remove the noise? How can I figure it out the values of Wp, Ws, Rs and Rp looking to this spectrogram?</li>
  </ul>