diff --git a/qml/PlayerScreen.qml b/qml/PlayerScreen.qml
index c76c094..cbdd515 100644
--- a/qml/PlayerScreen.qml
+++ b/qml/PlayerScreen.qml
@@ -138,7 +138,7 @@ Item {
 
 			theme: main.theme
 
-			marks: [1, 2, 3, 4, 5, 6, 7, 8, 9]
+			marks: [1, 2, 3, 4, 5, 6, 7, 8]
 			//nb_marks_displayed: is_portrait ? 4 : 3
 
 			width: parent.width * 0.6
diff --git a/qml/TunerScreen.qml b/qml/TunerScreen.qml
index b262429..c4261f9 100644
--- a/qml/TunerScreen.qml
+++ b/qml/TunerScreen.qml
@@ -141,7 +141,7 @@ Item {
 			anchors.rightMargin: is_portrait ? (parent.width - width) / 2 : parent.width / 20
 			theme: main.theme
 
-			marks: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
+			marks: [1, 2, 3, 4, 5, 6, 7, 8]
 			nb_marks_displayed: is_portrait ? 4 : 3
 
 			width: is_portrait ? meter.width / 2 : parent.width / 6
diff --git a/src/PitchDetection.cpp b/src/PitchDetection.cpp
index 83c2412..41a9e79 100644
--- a/src/PitchDetection.cpp
+++ b/src/PitchDetection.cpp
@@ -22,6 +22,13 @@
 
 using namespace std;
 
+/* with scpy:
+ *
+ * nyq=rate/2
+ * norm=cutoff/nyq
+ * b, a = butter(order, norm, btype='high', analog=False)
+ */
+
 // high 10hz / 16k
 static double a10[] = { 1        , -2.99214602,  2.98432286, -0.99217678 };
 static double b10[] = { 0.99608071, -2.98824212,  2.98824212, -0.99608071 };
diff --git a/src/PitchDetection.hpp b/src/PitchDetection.hpp
index 4f2be4f..edb11fa 100644
--- a/src/PitchDetection.hpp
+++ b/src/PitchDetection.hpp
@@ -46,15 +46,15 @@ class PitchDetection {
 	static const int rate = 16000;
 
 	private:
-	static const int defaultNbFrame = 1024;
-	static const int defaultFreqMin = 50;
-	static const int defaultFreqMax = 2000;
+	static const int defaultNbFrame = 2048;
+	static const int defaultFreqMin = 30;
+	static const int defaultFreqMax = 3000;
 	/// number of analyses to confirm a note
 	static const int nbConfirm = 3;
 	/// number of analyses to drop a note
-	static const int nbDefect = 20;
+	static const int nbDefect = 14;
 	/// number of deviation values for average
-	static const int nbDeviationValues = 8;
+	static const int nbDeviationValues = 4;
 
 	LinearFilter<int16_t> *high_filter;
 	ZeroCross<int16_t> *cross;