From: sgunderson@bigfoot.com <>
Date: Sat, 8 Dec 2007 14:41:39 +0000 (+0100)
Subject: Tuned a few parameters a bit to increase guitar tuning accuracy.
X-Git-Url: https://git.sesse.net/?p=pitch;a=commitdiff_plain;h=acfe6ba53cbe46bbc35959602c2835906e3467e7;hp=24d0e4fa9a93f86fffd7bca85510973c97dc0dec

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

diff --git a/pitchdetector.cpp b/pitchdetector.cpp
index cf0abe0..02c7035 100644
--- 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;
 		}
+#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) {
@@ -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
 
-	// 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 &&
-		    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
@@ -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 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);
 }