Filter out noise which was amplified by HPS

1 files changed, 5 insertions, 0 deletions

diff --git a/tuner.c b/tuner.c
index ec2ebb9..d2defcb 100644
--- a/tuner.c
+++ b/tuner.c
@@ -14,6 +14,7 @@
 #define FFT_SIZE (1<<13)
 
 #define ACCURACY 2.0 // Hz
+#define NOISE_FLOOR 30
 
 #define FFT_INDEX_TO_FREQ(i) ((float)i * SAMPLE_RATE / FFT_SIZE)
 
@@ -128,6 +129,10 @@ static void calculate_magnitudes()
 		/* +1 because out[0] is DC result */
 		magnitudes[i] = cabs(fft_out[i+1]);
 
+		if (magnitudes[i] < NOISE_FLOOR) {
+			magnitudes[i] = 0.0;
+		}
+
 		/* also find highest magnitude for later informational output */
 		if (magnitudes[i] > magnitudes[max_i]) {
 			max_i = i;