diff --git a/klippy/extras/shaper_calibrate.py b/klippy/extras/shaper_calibrate.py
index 1df4c943..71e5e489 100644
--- a/klippy/extras/shaper_calibrate.py
+++ b/klippy/extras/shaper_calibrate.py
@@ -139,6 +139,8 @@ class CalibrationData:
         self.psd_y = psd_y
         self.psd_z = psd_z
         self._psd_list = [self.psd_sum, self.psd_x, self.psd_y, self.psd_z]
+        self._psd_map = {'x': self.psd_x, 'y': self.psd_y, 'z': self.psd_z,
+                         'all': self.psd_sum}
         self.data_sets = 1
     def join(self, other):
         np = self.numpy
@@ -159,6 +161,8 @@ class CalibrationData:
             psd /= self.freq_bins + .1
             # Remove low-frequency noise
             psd[self.freq_bins < MIN_FREQ] = 0.
+    def get_psd(self, axis='all'):
+        return self._psd_map[axis]
 
 
 CalibrationResult = collections.namedtuple(
diff --git a/scripts/graph_accelerometer.py b/scripts/graph_accelerometer.py
index f6d7cf89..93dd413b 100755
--- a/scripts/graph_accelerometer.py
+++ b/scripts/graph_accelerometer.py
@@ -113,7 +113,7 @@ def plot_frequency(datas, lognames, max_freq):
     fig.tight_layout()
     return fig
 
-def plot_compare_frequency(datas, lognames, max_freq):
+def plot_compare_frequency(datas, lognames, max_freq, axis):
     fig, ax = matplotlib.pyplot.subplots()
     ax.set_title('Frequency responses comparison')
     ax.set_xlabel('Frequency (Hz)')
@@ -122,7 +122,7 @@ def plot_compare_frequency(datas, lognames, max_freq):
     for data, logname in zip(datas, lognames):
         calibration_data = calc_freq_response(data, max_freq)
         freqs = calibration_data.freq_bins
-        psd = calibration_data.psd_sum[freqs <= max_freq]
+        psd = calibration_data.get_psd(axis)[freqs <= max_freq]
         freqs = freqs[freqs <= max_freq]
         ax.plot(freqs, psd, label="\n".join(wrap(logname, 60)), alpha=0.6)
 
@@ -243,7 +243,8 @@ def main():
             opts.error("Only 1 input is supported in specgram mode")
         fig = plot_specgram(datas[0], args[0], options.max_freq, options.axis)
     elif options.compare:
-        fig = plot_compare_frequency(datas, args, options.max_freq)
+        fig = plot_compare_frequency(datas, args, options.max_freq,
+                                     options.axis)
     else:
         fig = plot_frequency(datas, args, options.max_freq)