diff --git a/main.cpp b/main.cpp
index cf04827..598e371 100644
--- a/main.cpp
+++ b/main.cpp
@@ -16,9 +16,10 @@ static constexpr int OFS   = 20;
 
 static CFFT fft (ORDER);
 static vector<double> mono;
-static bool sign = false;
+static bool odd = false;
 
 void cputs (const char * s) {
+  odd = ! odd;
   const complex plus (0.0, 256.0), minus (0.0, -256.0);
   complex data [TAPS];
   memset (&data,0, TAPS * sizeof(complex));
@@ -27,12 +28,12 @@ void cputs (const char * s) {
     const char c = s [n];
     if (c == '\0') break;
     if (c == '#' ) {
+      const bool sign = (n & 1) xor odd;
       // Střídání fáze 0/180 dost potlačí rozmazání spektra.
       const complex fill = sign ? plus : minus;
       const int k = n + OFS;
       data[k]        = fill;
       data[TAPS - k] = fill;
-      sign = ! sign;
     }
     putchar(c);
     n += 1;