diff --git a/src/sfizz/SynthMessaging.cpp b/src/sfizz/SynthMessaging.cpp
index 4e3285fa..cabb85ec 100644
--- a/src/sfizz/SynthMessaging.cpp
+++ b/src/sfizz/SynthMessaging.cpp
@@ -9,6 +9,8 @@
 #include <absl/strings/ascii.h>
 #include <cstring>
 
+// TODO: `ccModDepth` and `ccModParameters` are O(N), need better implementation
+
 namespace sfz {
 static constexpr unsigned maxIndices = 8;