diff --git a/compact_sets.py b/compact_sets.py
index 4c0a9ad..7c258a5 100644
--- a/compact_sets.py
+++ b/compact_sets.py
@@ -970,6 +970,18 @@ def write_chord_sequence_readable(seq: list[Chord], path: str) -> None:
         f.write(")\n")
 
 
+def write_chord_sequence_frequencies(
+    seq: list[Chord], path: str, fundamental: float = 100.0
+) -> None:
+    """Write chord sequence as frequencies in Hz - one line per chord."""
+    with open(path, "w") as f:
+        f.write("(\n")
+        for chord in seq:
+            freqs = tuple(fundamental * float(p.to_fraction()) for p in chord._pitches)
+            f.write(f"  {freqs},\n")
+        f.write(")\n")
+
+
 # ============================================================================
 # MAIN / DEMO
 # ============================================================================
@@ -1069,6 +1081,9 @@ def main():
     write_chord_sequence_readable(path, "output_chords.txt")
     print("Written to output_chords.txt")
 
+    write_chord_sequence_frequencies(path, "output_frequencies.txt")
+    print("Written to output_frequencies.txt")
+
 
 if __name__ == "__main__":
     main()