title: can I use AVAudioPlayer to make an equalizer player?
body: <p>I want to make an equalizer for music player,which can do some EQ setting like bass and treble,and I want to change the music effect by setting the frequency.<br>
  <em>250Hz</em>, <em>1000Hz</em>, <em>16000Hz</em>.</p>
  
  <pre><code>(void)setEQ:(@"250Hz");
  (void)setEQ:(@"1000Hz z");
  (void)setEQ:(@"16000Hz");
  </code></pre>
  
  <p>But I can not find any API of AVAudioPlayer to set frequency.Can anyone help me? I will be very grateful.</p>