Tuned a few parameters a bit to increase guitar tuning accuracy.

[pitch] / pitchdetector.cpp

diff --git a/pitchdetector.cpp b/pitchdetector.cpp
index cf0abe0d01fc313dd596aa44cdc956053c6b77cf..02c7035754e2bf9b4940ec4823e951345f900069 100644 (file)
--- a/pitchdetector.cpp
+++ b/pitchdetector.cpp
@@ -80,6 +80,13 @@ std::pair<double, double> PitchDetector::find_peak(double *in, unsigned num_samp
                        best_peak = in[i];
                        best_bin = i;
                }
                        best_peak = in[i];
                        best_bin = i;
                }

+#if 0
+               if (20.0 * log10(in[i] / fft_length) > 0.0) {
+                       printf("PEAK: %+4.2f dB   %5.2f Hz\n",
+                               20.0 * log10(in[i] / fft_length),
+                               bin_to_freq(i, num_samples));
+               }
+#endif

        }
        
        if (best_bin == 0 || best_bin == num_samples / 2) {
        }
        
        if (best_bin == 0 || best_bin == num_samples / 2) {


@@ -97,10 +104,10 @@ std::pair<double, double> PitchDetector::find_peak(double *in, unsigned num_samp
                20.0 * log10(in[best_bin/4] / fft_length));
 #endif
 
                20.0 * log10(in[best_bin/4] / fft_length));
 #endif
 

-       // see if we might have hit an overtone (set a limit of 5dB)
-       for (unsigned i = 4; i >= 1; --i) {
+       // see if we might have hit an overtone (set a limit of 10dB)
+       for (unsigned i = 6; i >= 1; --i) {

                if (best_bin != best_bin / i &&
                if (best_bin != best_bin / i &&

-                   20.0 * log10(in[best_bin] / in[best_bin / i]) < 5.0f) {
+                   20.0 * log10(in[best_bin] / in[best_bin / i]) < 10.0f) {

 #if 0
                        printf("Overtone of degree %u!\n", i);
 #endif
 #if 0
                        printf("Overtone of degree %u!\n", i);
 #endif


@@ -244,7 +251,7 @@ std::pair<double, double> PitchDetector::interpolate_peak(double ym1, double y0,
        double c = y0;
        
        double xmax = (ym1 - y1) / (2.0 * (y1 + ym1 - 2.0 * y0));
        double c = y0;
        
        double xmax = (ym1 - y1) / (2.0 * (y1 + ym1 - 2.0 * y0));

-       double ymax = 20.0 * (a * xmax * xmax + b * xmax + c) - 90.0;
+       double ymax = 20.0 * (a * xmax * xmax + b * xmax + c) - 80.0;

 
        return std::make_pair(xmax, ymax);
 }
 
        return std::make_pair(xmax, ymax);
 }