diff --git a/compact_sets.py b/compact_sets.py
index 2d8e4f0..9d3d785 100644
--- a/compact_sets.py
+++ b/compact_sets.py
@@ -517,8 +517,8 @@ class HarmonicSpace:
             # Transpose c2
             c2_transposed = c2.transpose(trans)
 
-            # Check symmetric difference on transposed pitches (not collapsed)
-            symdiff = self._calc_symdiff_expanded(c1, c2_transposed)
+            # Check symmetric difference
+            symdiff = self._calc_symdiff(c1, c2_transposed)
 
             if not (symdiff_range[0] <= symdiff <= symdiff_range[1]):
                 continue
@@ -656,10 +656,10 @@ class HarmonicSpace:
 
         return all_maps
 
-    def _calc_symdiff_expanded(self, c1: Chord, c2: Chord) -> int:
-        """Calculate symmetric difference on transposed (expanded) pitches.
+    def _calc_symdiff(self, c1: Chord, c2: Chord) -> int:
+        """Calculate symmetric difference between two chords.
 
-        Uses the transposed pitches directly without collapsing.
+        Uses the pitches directly.
         """
         set1 = set(c1.pitches)
         set2 = set(c2.pitches)