diff --git a/demos/wiener_filter_unit.py b/demos/wiener_filter_unit.py
index 0a3ca54e9fe649d08d2751a3fc469b64e78d8fde..2065626903e52a9e57dd4c2a6ef5613982a50552 100644
--- a/demos/wiener_filter_unit.py
+++ b/demos/wiener_filter_unit.py
@@ -83,10 +83,10 @@ if __name__ == "__main__":
     a_s = sigma_s ** 2. * lambda_s * total_volume
 
     # creation of spaces
-    x1 = RGSpace(npix, dtype=np.float64, distances=total_volume / npix,
+    x1 = RGSpace(npix, distances=total_volume / npix,
                  zerocenter=False)
     k1 = RGRGTransformation.get_codomain(x1)
-    p1 = PowerSpace(harmonic_domain=k1, log=False, dtype=np.float64)
+    p1 = PowerSpace(harmonic_domain=k1, log=False)
 
     # creating Power Operator with given spectrum
     spec = (lambda k: a_s / (1 + (k / k_0) ** 2) ** 2)
@@ -97,8 +97,8 @@ if __name__ == "__main__":
     Fft_op = FFTOperator(domain=x1, target=k1,
                         domain_dtype=np.float64,
                         target_dtype=np.complex128)
-    R_op = ResponseOperator(x1, sigma=length_convolution,
-                            exposure=exposure)
+    R_op = ResponseOperator(x1, sigma=[length_convolution],
+                            exposure=[exposure])
 
     # drawing a random field
     sk = p_field.power_synthesize(real_signal=True, mean=0.)