diff --git a/configure.ac b/configure.ac
index fa9887f..885270e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -51,7 +51,7 @@ AC_MSG_CHECKING(whether to compile debug version)
 AC_ARG_ENABLE(debug,
   [  --enable-debug = enable various debug output],
   [AC_SUBST( cppflag, ["-D_STK_DEBUG_ -D__RTAUDIO_DEBUG__ -D__RTMIDI_DEBUG__"] ) AC_SUBST( cxxflag, ["-g"] ) AC_SUBST( object_path, [Debug] ) AC_MSG_RESULT(yes)],
-  [AC_SUBST( cppflag, [] ) AC_SUBST( cxxflag, [-O3] ) AC_SUBST( object_path, [Release] ) AC_MSG_RESULT(no)])
+  [AC_SUBST( cppflag, [] ) AC_SUBST( cxxflag, [] ) AC_SUBST( object_path, [Release] ) AC_MSG_RESULT(no)])
 
 # Checks for functions
 if test $realtime = yes; then
@@ -63,7 +63,7 @@ fi
 CPPFLAGS="$CPPFLAGS $cppflag"
 
 # For debugging and optimization ... overwrite default because it has both -g and -O2
-CXXFLAGS="$cxxflag"
+CXXFLAGS="$CXXFLAGS $cxxflag"
 
 # Check compiler and use -Wall if gnu.
 if [test $GXX = "yes" ;] then