diff -upr a/src/s3m.cpp b/src/s3m.cpp
--- a/src/s3m.cpp	2006-07-02 00:27:00.000000000 -0500
+++ b/src/s3m.cpp	2016-03-07 23:20:56.039017533 -0600
@@ -25,7 +25,7 @@
 #include <cstring>
 #include "s3m.h"
 
-const char Cs3mPlayer::chnresolv[] =	// S3M -> adlib channel conversion
+const signed char Cs3mPlayer::chnresolv[] =	// S3M -> adlib channel conversion
   {-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,0,1,2,3,4,5,6,7,8,-1,-1,-1,-1,-1,-1,-1};
 
 const unsigned short Cs3mPlayer::notetable[12] =		// S3M adlib note table
--- a/src/s3m.h	2006-05-13 00:36:42.000000000 -0500
+++ b/src/s3m.h	2016-03-08 00:56:07.953972552 -0600
@@ -90,7 +90,7 @@ class Cs3mPlayer: public CPlayer
   unsigned char crow,ord,speed,tempo,del,songend,loopstart,loopcnt;
 
  private:
-  static const char chnresolv[];
+  static const signed char chnresolv[];
   static const unsigned short notetable[12];
   static const unsigned char vibratotab[32];