diff --git a/code/nel/include/nel/sound/driver/sound_driver.h b/code/nel/include/nel/sound/driver/sound_driver.h
index 2fa450249..c9551f16b 100644
--- a/code/nel/include/nel/sound/driver/sound_driver.h
+++ b/code/nel/include/nel/sound/driver/sound_driver.h
@@ -39,7 +39,9 @@ namespace NLSOUND
 #endif
 
 /*
- * Sound sample format
+ * Deprecated sound sample format.
+ * For compatibility with old code.
+ * Do not modify.
  */
 enum TSampleFormat { Mono8, Mono16ADPCM, Mono16, Stereo8, Stereo16, SampleFormatUnknown = (~0) };