diff --git a/src/agora/io/signal.py b/src/agora/io/signal.py
index 08e4c94495f32b3266164a3a8dc6b0e9179bd783..8ed24186d6373e0c7cd5981699a84445bd19d807 100644
--- a/src/agora/io/signal.py
+++ b/src/agora/io/signal.py
@@ -47,7 +47,7 @@ class Signal(BridgeH5):
     def __getitem__(self, dsets: t.Union[str, t.Collection]):
         """Get and potentially pre-process data from h5 file and return as a dataframe."""
         if isinstance(dsets, str):  # no pre-processing
-            df = self.get_raw(dsets)
+            df = self.apply_prepost(dsets)
             return self.add_name(df, dsets)
         elif isinstance(dsets, list):  # pre-processing
             is_bgd = [dset.endswith("imBackground") for dset in dsets]