title: librosa producing "undetailed" MFCC spectrogram
body: <p>I am trying to create an MFCC plot with librosa but the plot just doesn't appear to be very detailed. The goal is to present this MFCC spectrogram to a neural network. The audio file I am testing with is around 1 second long and is from the Google Speech Commands dataset. My code is:</p>
  
  <pre class="lang-py prettyprint-override"><code>WINDOW_SIZE = 20
  NFFT=int((WINDOW_SIZE/1000)*16000)
  
  samples, _ = librosa.load(f, sr=16000) 
  
  mfccs = librosa.feature.mfcc(y=samples[:16000], sr=16000, n_fft=NFFT, n_mfcc=40)
  
  plt.figure(figsize=(10, 4))
  librosa.display.specshow(mfccs, x_axis='time')
  plt.colorbar()
  plt.title('MFCC')
  plt.tight_layout()
  plt.show()
  </code></pre>
  
  <p>This is the MFCC spectrogram being produced:</p>
  
  <p><a href="https://i.stack.imgur.com/4TKqd.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/4TKqd.png" alt="mfcc spec"></a></p>