diff --git a/src/reskit/soundtrack.rs b/src/reskit/soundtrack.rs
index 4c4bdf0..b31ed2c 100644
--- a/src/reskit/soundtrack.rs
+++ b/src/reskit/soundtrack.rs
@@ -595,7 +595,7 @@ impl DmfModule {
                                 9 => Note::A( octave ),
                                 10 => Note::ASharp( octave ),
                                 11 => Note::B( octave ),
-                                12 => Note::C( octave ),
+                                12 => Note::C( octave + 1 ), // deflemask y u shift the octave down 1 for C??
                                 _ => return Err( format!( "invalid file: invalid note id {}", note ) )?
                             }
                         )