diff --git a/padertorch/summary/tbx_utils.py b/padertorch/summary/tbx_utils.py
index 09c26f33..8076d756 100644
--- a/padertorch/summary/tbx_utils.py
+++ b/padertorch/summary/tbx_utils.py
@@ -79,7 +79,7 @@ def mask_to_image(
             is assumed to be in the second position, i.e.,
             `(frames, batch [optional], features)`.
         color: A color map name. The name is forwarded to
-               `matplotlib.pyplot.cm.get_cmap` to get the color map. If `None`,
+               `matplotlib.pyplot.get_cmap` to get the color map. If `None`,
                grayscale is used.
         origin: Origin of the plot. Can be `'upper'` or `'lower'`.
 
@@ -119,7 +119,7 @@ def stft_to_image(
         signal: Shape (frames, batch [optional], features)
         batch_first: if true mask shape (batch [optional], frames, features]
         color: A color map name. The name is forwarded to
-               `matplotlib.pyplot.cm.get_cmap` to get the color map. If `None`,
+               `matplotlib.pyplot.get_cmap` to get the color map. If `None`,
                grayscale is used.
         origin: Origin of the plot. Can be `'upper'` or `'lower'`.
         visible_dB: How many dezibel are visible in the image.
@@ -203,7 +203,7 @@ def __call__(self, image, color):
             except KeyError:
                 try:
                     import matplotlib.pyplot as plt
-                    cmap = plt.cm.get_cmap(color)
+                    cmap = plt.get_cmap(color)
                     self.color_to_cmap[color] = cmap
                 except ImportError:
                     from warnings import warn
@@ -243,7 +243,7 @@ def spectrogram_to_image(
             is assumed to be in the second position, i.e.,
             `(frames, batch [optional], features)`.
         color: A color map name. The name is forwarded to
-               `matplotlib.pyplot.cm.get_cmap` to get the color map.
+               `matplotlib.pyplot.get_cmap` to get the color map.
         origin: Origin of the plot. Can be `'upper'` or `'lower'`.
         log: If `True`, the spectrogram is plotted in log domain and shows a
             50dB range. The 50dB can be changed with the argument `visible_dB`.
@@ -299,6 +299,9 @@ def audio(
         docs for further information on the return type.
     """
     signal = to_numpy(signal, detach=True)
+    if signal.dtype.kind == 'c':
+        raise ValueError(
+            f'Complex datatype ({signal.dtype}) is not supported for audio.')
 
     signal = _remove_batch_axis(signal, batch_first=batch_first, ndim=1)
 
@@ -454,3 +457,5 @@ def review_dict(
     assert operator.xor(loss is None, losses is None), (loss, losses)
 
     return review
+
+