diff --git a/shared-module/synthio/__init__.c b/shared-module/synthio/__init__.c
index 1385059b99..c7e1096632 100644
--- a/shared-module/synthio/__init__.c
+++ b/shared-module/synthio/__init__.c
@@ -31,7 +31,7 @@
 #include <math.h>
 #include <stdlib.h>
 
-STATIC const int16_t square_wave[] = {-32768, 0};
+STATIC const int16_t square_wave[] = {-32768, 32767};
 
 STATIC const uint16_t notes[] = {8372, 8870, 9397, 9956, 10548, 11175, 11840,
                                  12544, 13290, 14080, 14917, 15804}; // 9th octave
diff --git a/tests/circuitpython-manual/synthio/.gitignore b/tests/circuitpython-manual/synthio/.gitignore
new file mode 100644
index 0000000000..d8dd7532ab
--- /dev/null
+++ b/tests/circuitpython-manual/synthio/.gitignore
@@ -0,0 +1 @@
+*.wav
diff --git a/tests/circuitpython-manual/synthio/wave/.gitignore b/tests/circuitpython-manual/synthio/wave/.gitignore
deleted file mode 100644
index c212df9c3d..0000000000
--- a/tests/circuitpython-manual/synthio/wave/.gitignore
+++ /dev/null
@@ -1 +0,0 @@
-tune.wav
diff --git a/tests/circuitpython/miditrack.py.exp b/tests/circuitpython/miditrack.py.exp
index 2d9e2548a0..6de9f947c6 100644
--- a/tests/circuitpython/miditrack.py.exp
+++ b/tests/circuitpython/miditrack.py.exp
@@ -1,4 +1,4 @@
 (0, 1, 512, 1)
-1 [-16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, 0, 0]
+1 [-16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 16382, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, -16383, 16382, 16382]
 (0, 1, 512, 1)
 1 [0, 0, 0, 0, 0, 0, 16382, 16382, 16382, 16382, 16382, 16382, 0, 0, 0, 0, 0, 0, -16383, -16383, -16383, -16383, -16383, -16383, 0, 0, 0, 0, 0, 0, 16382, 16382, 16382, 16382, 16382, 16382, 0, 0, 0, 0, 0, 0, -16383, -16383, -16383, -16383, -16383, -16383, 0, 0, 0, 0, 0, 0, 16382, 16382, 16382, 16382, 16382, 16382, 0, 0, 0, 0, 0, 0, -16383, -16383, -16383, -16383, -16383, -16383, 0, 0, 0, 0, 0, 0, 16382, 16382, 16382, 16382, 16382, 16382, 0, 0, 0, 0, 0, 0, 0, -16383, -16383, -16383, -16383, -16383, -16383, 0, 0, 0, 0, 0, 0, 16382, 16382, 16382, 16382, 16382, 16382, 0, 0, 0, 0, 0, 0, -16383, -16383, -16383, -16383, -16383, -16383, 0, 0, 0, 0, 0, 0, 16382, 16382, 16382, 16382, 16382, 16382, 0, 0, 0, 0, 0, 0, -16383, -16383, -16383, -16383, -16383, -16383, 0, 0, 0, 0, 0, 0, 16382, 16382, 16382, 16382, 16382, 16382, 0, 0, 0, 0, 0, 0, -16383, -16383, -16383, -16383, -16383, -16383, 0, 0, 0, 0, 0, 0, 16382, 16382, 16382, 16382, 16382, 16382, 16382, 0, 0, 0, 0, 0, 0, -16383, -16383, -16383, -16383, -16383, -16383, 0, 0, 0, 0, 0, 0, 16382, 16382, 16382, 16382, 16382, 16382, 0, 0, 0, 0, 0, 0, -16383, -16383, -16383, -16383, -16383, -16383, 0, 0, 0, 0, 0, 0, 16382, 16382, 16382, 16382, 16382, 16382, 0, 0, 0, 0, 0, 0, -16383, -16383, -16383, -16383, -16383, -16383, 0, 0, 0, 0, 0, 0, 16382, 16382, 16382, 16382, 16382, 16382, 0, 0]
diff --git a/tests/circuitpython/synthesizer.py.exp b/tests/circuitpython/synthesizer.py.exp
index 70eb647bab..826290fe27 100644
--- a/tests/circuitpython/synthesizer.py.exp
+++ b/tests/circuitpython/synthesizer.py.exp
@@ -1,30 +1,30 @@
 ()
 [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
 (80,)
-[-16383, -16383, -16383, -16383, 0, 0, 0, 0, 0, -16383, -16383, -16383, -16383, -16383, 0, 0, 0, 0, 0, -16383, -16383, -16383, -16383, -16383]
+[-16383, -16383, -16383, -16383, 16382, 16382, 16382, 16382, 16382, -16383, -16383, -16383, -16383, -16383, 16382, 16382, 16382, 16382, 16382, -16383, -16383, -16383, -16383, -16383]
 (80, 91)
-[-8191, -8191, 0, 0, -8191, -16382, -16382, -8191, 0, 0, -8191, -8191, 0, -8191, -8191, -16382, -16382, -8191, 0, 0, -8191, -8191, 0, -8191]
+[0, 0, 16382, 16382, 0, -16382, -16382, 0, 16382, 16382, 0, 0, 16382, 0, 0, -16382, -16382, 0, 16382, 16382, 0, 0, 16382, 0]
 (91,)
-[-16382, -8191, -8191, 0, -8191, -8191, 0, 0, -8191, -16382, -16382, -8191, 0, 0, -8191, -8191, 0, -8191, -8191, -16382, -16382, -16382, 0, 0]
-(-5242, 0)
-(-10484, 0)
-(-15727, 0)
-(-16383, 0)
-(-14286, 0)
-(-13106, 0)
-(-13106, 0)
-(-13106, 0)
-(-13106, 0)
-(-13106, 0)
-(-13106, 0)
-(-13106, 0)
-(-13106, 0)
-(-11009, 0)
-(-8912, 0)
-(-6815, 0)
-(-4718, 0)
-(-2621, 0)
-(-524, 0)
+[-16382, 0, 0, 16382, 0, 0, 16382, 16382, 0, -16382, -16382, 0, 16382, 16382, 0, 0, 16382, 0, 0, -16382, -16382, -16382, 16382, 16382]
+(-5242, 5241)
+(-10484, 10484)
+(-15727, 15726)
+(-16383, 16382)
+(-14286, 14285)
+(-13106, 13105)
+(-13106, 13105)
+(-13106, 13105)
+(-13106, 13105)
+(-13106, 13105)
+(-13106, 13105)
+(-13106, 13105)
+(-13106, 13105)
+(-11009, 11008)
+(-8912, 8911)
+(-6815, 6814)
+(-4718, 4717)
+(-2621, 2620)
+(-524, 523)
 (0, 0)
 (0, 0)
 (0, 0)