diff --git a/lasp/lasp_avstream.py b/lasp/lasp_avstream.py
index 58f24d9..283b25b 100644
--- a/lasp/lasp_avstream.py
+++ b/lasp/lasp_avstream.py
@@ -157,6 +157,14 @@ class AudioStream:
             return 1
         self.aframectr += 1                
 
+        # TODO: Fix this. This gives bug on Windows, the threading lock does
+        # give a strange erro.
+        try:
+            if not self.running():
+                return 1
+        except Exception as e:
+            print(e)
+
         rv = self.processCallback(self, indata, outdata)
         if rv != 0:
             self.running <<= False
diff --git a/lasp/lasp_measurement.py b/lasp/lasp_measurement.py
index 76d0c25..94120ee 100644
--- a/lasp/lasp_measurement.py
+++ b/lasp/lasp_measurement.py
@@ -246,7 +246,7 @@ class Measurement:
             except KeyError:
                 # If quantity data is not available, this is an 'old'
                 # measurement file.
-                logging.debug('Physical quantity data not available in measurement file. Assuming {SIQtys.default}')
+                logging.debug(f'Physical quantity data not available in measurement file. Assuming {SIQtys.default}')
                 self._qtys = [SIQtys.default for i in range(self.nchannels)]
 
     def setAttribute(self, atrname, value):
diff --git a/lasp/tools/tools.py b/lasp/tools/tools.py
index 07b88ca..742f7b0 100644
--- a/lasp/tools/tools.py
+++ b/lasp/tools/tools.py
@@ -84,6 +84,7 @@ def smoothSpectralData(freq, M, sw: SmoothingWidth,
     assert Noct > 0, "'Noct' must be absolute positive"
     if Noct < 1: raise Warning('Check if \'Noct\' is entered correctly')
     assert len(freq)==len(M), 'f and M should have equal length'
+
     if st == SmoothingType.ps:
         assert np.min(M) >= 0, 'absolute magnitude M cannot be negative'
     if st == SmoothingType.levels and isinstance(M.dtype, complex):