diff --git a/src/lasp/lasp_measurement.py b/src/lasp/lasp_measurement.py
index 587e421..fc5364c 100644
--- a/src/lasp/lasp_measurement.py
+++ b/src/lasp/lasp_measurement.py
@@ -50,7 +50,7 @@ from .lasp_config import LASP_NUMPY_FLOAT_TYPE
 from scipy.io import wavfile
 import os, time, wave, logging
 from .lasp_common import SIQtys, Qty, getFreq
-from .lasp_cpp import Window, DaqChannel, LASP_VERSION_MAJOR
+from .lasp_cpp import Window, DaqChannel, LASP_VERSION_MAJOR, AvPowerSpectra
 from typing import List
 
 
@@ -480,18 +480,18 @@ class Measurement:
 
         """
         nfft = kwargs.pop('nfft', 2048)
-        window = kwargs.pop('window', Window.hann)
+        window = kwargs.pop('windowType', Window.WindowType.Hann)
         overlap = kwargs.pop('overlap', 50.0)
 
         if channels is None:
             channels = list(range(self.nchannels))
 
         nchannels = len(channels)
-        aps = AvPowerSpectra(nfft, nchannels, overlap, window)
+        aps = AvPowerSpectra(nfft, window, overlap)
         freq = getFreq(self.samplerate, nfft)
 
         for data in self.iterData(channels, **kwargs):
-            CS = aps.addTimeData(data)
+            CS = aps.compute(data)
 
         return freq, CS