diff --git a/pyrubberband/pyrb.py b/pyrubberband/pyrb.py
index 57597fb..b7879d3 100644
--- a/pyrubberband/pyrb.py
+++ b/pyrubberband/pyrb.py
@@ -19,7 +19,7 @@
 import soundfile as sf
 
 
-__all__ = ['time_stretch', 'pitch_shift', 'timemap_stretch']
+__all__ = ['time_stretch', 'pitch_shift', 'timemap_stretch', 'frequency_multiply', 'change_tempo']
 
 __RUBBERBAND_UTIL = 'rubberband'
 
@@ -255,3 +255,78 @@ def pitch_shift(y, sr, n_steps, rbargs=None):
     rbargs.setdefault('--pitch', n_steps)
 
     return __rubberband(y, sr, **rbargs)
+
+
+def frequency_multiply(y, sr, X, rbargs=None):
+    '''Multiply the frequencies inside an audio time series.
+    The equivalent of the -f option.
+    Parameters
+    ----------
+    y : np.ndarray [shape=(n,) or (n, c)]
+        Audio time series, either single or multichannel
+
+    sr : int > 0
+        Sampling rate of `y`
+
+    X : float
+        Shift magnitudes in spectrum by X
+
+    rbargs
+        Additional keyword parameters for rubberband
+
+        See `rubberband -h` for details.
+
+    Returns
+    -------
+    y_shift : np.ndarray
+        frequency-multiplied audio
+    '''
+
+    if X == 0:
+        return y
+
+    if rbargs is None:
+        rbargs = dict()
+
+    rbargs.setdefault('--frequency', X)
+
+    return __rubberband(y, sr, **rbargs)
+
+
+def change_tempo(y, sr, X, Y, rbargs=None):
+    '''Multiply the frequencies inside an audio time series.
+    The equivalent of the --tempo <X>:<Y> option.
+    Parameters
+    ----------
+    y : np.ndarray [shape=(n,) or (n, c)]
+        Audio time series, either single or multichannel
+
+    sr : int > 0
+        Sampling rate of `y`
+
+    X : float
+        Base tempo
+
+    Y : float
+        Final tempo
+
+    rbargs
+        Additional keyword parameters for rubberband
+
+        See `rubberband -h` for details.
+
+    Returns
+    -------
+    y_shift : np.ndarray
+        tempo-shifted audio
+    '''
+
+    if X == 0:
+        return y
+
+    if rbargs is None:
+        rbargs = dict()
+
+    rbargs.setdefault('--tempo', '%s:%s' % (X, Y))
+
+    return __rubberband(y, sr, **rbargs)