diff --git a/.gitignore b/.gitignore
index 47ac4bd..024f9a2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -65,7 +65,7 @@ ipython_config.py
 #   pdm stores project-wide configurations in .pdm.toml, but it is recommended to not include it
 #   in version control.
 #   https://pdm.fming.dev/#use-with-ide
-.pdm.toml
+.pdm-python
 
 # PEP 582; used by e.g. github.com/David-OConnor/pyflow and github.com/pdm-project/pdm
 __pypackages__/
diff --git a/batdetect2/detector/compute_features.py b/batdetect2/detector/compute_features.py
index 6abb145..e0c3a2d 100644
--- a/batdetect2/detector/compute_features.py
+++ b/batdetect2/detector/compute_features.py
@@ -100,7 +100,7 @@ def compute_max_power_bb(
     max_power_ind = np.argmax(power_per_freq_band)
     return int(
         convert_int_to_freq(
-            max_power_ind,
+            y_low - max_power_ind,
             spec.shape[0],
             min_freq,
             max_freq,
@@ -190,13 +190,13 @@ def compute_max_power_second(
 
 def compute_call_interval(
     prediction: types.Prediction,
-    previous_prediction: Optional[types.Prediction] = None,
+    previous: Optional[types.Prediction] = None,
     **_,
 ) -> float:
     """Compute time between this call and the previous call in seconds."""
-    if previous_prediction is None:
+    if previous is None:
         return np.nan
-    return round(prediction["start_time"] - previous_prediction["end_time"], 5)
+    return round(prediction["start_time"] - previous["end_time"], 5)
 
 
 # NOTE: The order of the features in this dictionary is important. The