disable unnecessary magphase in plot_presets

melspectrogram does not produce complex values
revert 9eb902d

docs/examples/plot_presets.py

@@ -61,30 +61,23 @@
 filename = 'audio/Karissa_Hobbs_-_09_-_Lets_Go_Fishin.mp3'
 y, sr = librosa.load(filename, duration=5, offset=35)
 
-# Generate a complex-valued mel spectrogram:
+# Generate a mel spectrogram:
 M = librosa.feature.melspectrogram(y=y)
 
-
-# Extract magnitudes and phases from complex time-frequency bins in M:
-M_mag, M_phase = librosa.magphase(M)
-
-
 # Of course, you can still override the new default manually, e.g.:
 M_hop512 = librosa.feature.melspectrogram(y=y, hop_length=512)
-M_hop512_mag = librosa.magphase(M)[0]
-
 
 # And plot the results
 plt.figure(figsize=(6, 6))
 ax = plt.subplot(3, 1, 1)
 
-librosa.display.specshow(librosa.amplitude_to_db(M_mag, ref=np.max),
+librosa.display.specshow(librosa.amplitude_to_db(M, ref=np.max),
                          y_axis='mel', x_axis='time')
 
 plt.title('44100/1024/4096')
 
 plt.subplot(3, 1, 2, sharex=ax, sharey=ax)
-librosa.display.specshow(librosa.amplitude_to_db(M_hop512_mag, ref=np.max),
+librosa.display.specshow(librosa.amplitude_to_db(M_hop512, ref=np.max),
                          hop_length=512,
                          y_axis='mel', x_axis='time')
 plt.title('44100/512/4096')
@@ -95,10 +88,9 @@
 
 y2, sr2 = librosa.load(filename, duration=5, offset=35)
 M_11k = librosa.feature.melspectrogram(y=y2, sr=sr2)
-M_11k_mag = librosa.magphase(M_11k)[0]
 
 plt.subplot(3, 1, 3, sharex=ax, sharey=ax)
-librosa.display.specshow(librosa.amplitude_to_db(M_11k_mag, ref=np.max),
+librosa.display.specshow(librosa.amplitude_to_db(M_11k, ref=np.max),
                          y_axis='mel', x_axis='time')
 
 plt.title('11025/1024/4096')