diff --git a/bilby/gw/source.py b/bilby/gw/source.py
index 9a85ae51ed15bf44e82057d3c1892149cd7a6009..6721f6cdde36a85a6ba8d50b8b792a99dfbea891 100644
--- a/bilby/gw/source.py
+++ b/bilby/gw/source.py
@@ -384,9 +384,9 @@ def _base_lal_cbc_fd_waveform(
 
     if len(hplus.data.data) > len(frequency_array):
         logger.debug("LALsim waveform longer than bilby's `frequency_array`" +
-                    "({} vs {}), ".format(len(hplus.data.data), len(frequency_array)) +
-                    "probably because padded with zeros up to the next power of two length." +
-                    " Truncating lalsim array.")
+                     "({} vs {}), ".format(len(hplus.data.data), len(frequency_array)) +
+                     "probably because padded with zeros up to the next power of two length." +
+                     " Truncating lalsim array.")
         h_plus = hplus.data.data[:len(h_plus)]
         h_cross = hcross.data.data[:len(h_cross)]