diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3fc3786..31d9e18 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,8 @@ All notable changes to `audioinstruments` are recorded here.
 
 ## Unreleased
 
+## 0.5.1.dev4
+
 - Acid303 has twelve patches, from Squelch and Screamer to Sub Thump and Zap, and
   `examples/acid303_demo.py` plays them. They accent a note struck hard and slide a note
   played over another. Init is as it was, except that a key now sounds at its own pitch:
diff --git a/VERSION b/VERSION
index 636eb88..5a3585c 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.5.1.dev3
+0.5.1.dev4
diff --git a/lib/audioinstruments/acid303.py b/lib/audioinstruments/acid303.py
index 63d4d46..5389e7f 100644
--- a/lib/audioinstruments/acid303.py
+++ b/lib/audioinstruments/acid303.py
@@ -6,7 +6,7 @@
 NAME = "acid303"
 DISPLAY_NAME = "Acid303"
 CATEGORIES = ("Synth",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/bass_pedals.py b/lib/audioinstruments/bass_pedals.py
index c5b31c1..ed710ef 100644
--- a/lib/audioinstruments/bass_pedals.py
+++ b/lib/audioinstruments/bass_pedals.py
@@ -6,7 +6,7 @@
 NAME = "bass_pedals"
 DISPLAY_NAME = "Bass Pedals"
 CATEGORIES = ("Synth",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/clavichord.py b/lib/audioinstruments/clavichord.py
index dbe3453..cace730 100644
--- a/lib/audioinstruments/clavichord.py
+++ b/lib/audioinstruments/clavichord.py
@@ -6,7 +6,7 @@
 NAME = "clavichord"
 DISPLAY_NAME = "Clavichord"
 CATEGORIES = ("Synth",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/combo_organ.py b/lib/audioinstruments/combo_organ.py
index c98be07..0703728 100644
--- a/lib/audioinstruments/combo_organ.py
+++ b/lib/audioinstruments/combo_organ.py
@@ -6,7 +6,7 @@
 NAME = "combo_organ"
 DISPLAY_NAME = "ComboOrgan"
 CATEGORIES = ("Synth",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/compact_organ.py b/lib/audioinstruments/compact_organ.py
index 9561804..38e4c51 100644
--- a/lib/audioinstruments/compact_organ.py
+++ b/lib/audioinstruments/compact_organ.py
@@ -6,7 +6,7 @@
 NAME = "compact_organ"
 DISPLAY_NAME = "Compact Organ"
 CATEGORIES = ("Synth",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/duo20.py b/lib/audioinstruments/duo20.py
index 02c5d89..f387154 100644
--- a/lib/audioinstruments/duo20.py
+++ b/lib/audioinstruments/duo20.py
@@ -6,7 +6,7 @@
 NAME = "duo20"
 DISPLAY_NAME = "Duo20"
 CATEGORIES = ("Synth",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/duosynth.py b/lib/audioinstruments/duosynth.py
index 8c7fe6c..f74cd88 100644
--- a/lib/audioinstruments/duosynth.py
+++ b/lib/audioinstruments/duosynth.py
@@ -6,7 +6,7 @@
 NAME = "duosynth"
 DISPLAY_NAME = "DuoSynth"
 CATEGORIES = ("Synth",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/electric_grand70.py b/lib/audioinstruments/electric_grand70.py
index 7f91662..e4bdd5b 100644
--- a/lib/audioinstruments/electric_grand70.py
+++ b/lib/audioinstruments/electric_grand70.py
@@ -6,7 +6,7 @@
 NAME = "electric_grand70"
 DISPLAY_NAME = "ElectricGrand70"
 CATEGORIES = ("Synth",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/electric_piano.py b/lib/audioinstruments/electric_piano.py
index 298299f..e245304 100644
--- a/lib/audioinstruments/electric_piano.py
+++ b/lib/audioinstruments/electric_piano.py
@@ -6,7 +6,7 @@
 NAME = "electric_piano"
 DISPLAY_NAME = "Electric Piano"
 CATEGORIES = ("Piano",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/electronic_drums5.py b/lib/audioinstruments/electronic_drums5.py
index 1908c3b..ece3a51 100644
--- a/lib/audioinstruments/electronic_drums5.py
+++ b/lib/audioinstruments/electronic_drums5.py
@@ -6,7 +6,7 @@
 NAME = "electronic_drums5"
 DISPLAY_NAME = "ElectronicDrums5"
 CATEGORIES = ("Drum",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/hybrid_mono.py b/lib/audioinstruments/hybrid_mono.py
index 34f2744..4e35fcb 100644
--- a/lib/audioinstruments/hybrid_mono.py
+++ b/lib/audioinstruments/hybrid_mono.py
@@ -6,7 +6,7 @@
 NAME = "hybrid_mono"
 DISPLAY_NAME = "HybridMono"
 CATEGORIES = ("Synth",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/mono101.py b/lib/audioinstruments/mono101.py
index a349252..0db3a7d 100644
--- a/lib/audioinstruments/mono101.py
+++ b/lib/audioinstruments/mono101.py
@@ -6,7 +6,7 @@
 NAME = "mono101"
 DISPLAY_NAME = "Mono101"
 CATEGORIES = ("Synth",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/mono_one.py b/lib/audioinstruments/mono_one.py
index a5582e6..ee335eb 100644
--- a/lib/audioinstruments/mono_one.py
+++ b/lib/audioinstruments/mono_one.py
@@ -6,7 +6,7 @@
 NAME = "mono_one"
 DISPLAY_NAME = "MonoOne"
 CATEGORIES = ("Synth",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/mono_synth.py b/lib/audioinstruments/mono_synth.py
index 39d2917..f0af5a5 100644
--- a/lib/audioinstruments/mono_synth.py
+++ b/lib/audioinstruments/mono_synth.py
@@ -6,7 +6,7 @@
 NAME = "mono_synth"
 DISPLAY_NAME = "Mono Synth"
 CATEGORIES = ("Synth",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/patch2600.py b/lib/audioinstruments/patch2600.py
index 780a22f..9eb6999 100644
--- a/lib/audioinstruments/patch2600.py
+++ b/lib/audioinstruments/patch2600.py
@@ -6,7 +6,7 @@
 NAME = "patch2600"
 DISPLAY_NAME = "Patch2600"
 CATEGORIES = ("Synth",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/poly106.py b/lib/audioinstruments/poly106.py
index f8d8b02..ad4bb1d 100644
--- a/lib/audioinstruments/poly106.py
+++ b/lib/audioinstruments/poly106.py
@@ -6,7 +6,7 @@
 NAME = "poly106"
 DISPLAY_NAME = "Poly106"
 CATEGORIES = ("Synth",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/poly5.py b/lib/audioinstruments/poly5.py
index 0bd5d60..cbec58d 100644
--- a/lib/audioinstruments/poly5.py
+++ b/lib/audioinstruments/poly5.py
@@ -6,7 +6,7 @@
 NAME = "poly5"
 DISPLAY_NAME = "Poly5"
 CATEGORIES = ("Synth",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/poly6.py b/lib/audioinstruments/poly6.py
index 14fac12..36cb5a1 100644
--- a/lib/audioinstruments/poly6.py
+++ b/lib/audioinstruments/poly6.py
@@ -6,7 +6,7 @@
 NAME = "poly6"
 DISPLAY_NAME = "Poly6"
 CATEGORIES = ("Synth",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/poly8.py b/lib/audioinstruments/poly8.py
index 0d90630..c89ab5f 100644
--- a/lib/audioinstruments/poly8.py
+++ b/lib/audioinstruments/poly8.py
@@ -6,7 +6,7 @@
 NAME = "poly8"
 DISPLAY_NAME = "Poly8"
 CATEGORIES = ("Synth",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/poly80.py b/lib/audioinstruments/poly80.py
index 3a69543..5dfe133 100644
--- a/lib/audioinstruments/poly80.py
+++ b/lib/audioinstruments/poly80.py
@@ -6,7 +6,7 @@
 NAME = "poly80"
 DISPLAY_NAME = "Poly80"
 CATEGORIES = ("Synth",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/polya6.py b/lib/audioinstruments/polya6.py
index a794c32..641fff4 100644
--- a/lib/audioinstruments/polya6.py
+++ b/lib/audioinstruments/polya6.py
@@ -6,7 +6,7 @@
 NAME = "polya6"
 DISPLAY_NAME = "PolyA6"
 CATEGORIES = ("Synth",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/polyxa.py b/lib/audioinstruments/polyxa.py
index 503ceb6..92bed97 100644
--- a/lib/audioinstruments/polyxa.py
+++ b/lib/audioinstruments/polyxa.py
@@ -6,7 +6,7 @@
 NAME = "polyxa"
 DISPLAY_NAME = "PolyXa"
 CATEGORIES = ("Synth",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/reed_piano.py b/lib/audioinstruments/reed_piano.py
index d66a666..a577d5d 100644
--- a/lib/audioinstruments/reed_piano.py
+++ b/lib/audioinstruments/reed_piano.py
@@ -6,7 +6,7 @@
 NAME = "reed_piano"
 DISPLAY_NAME = "ReedPiano"
 CATEGORIES = ("Synth",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/reed_piano200a.py b/lib/audioinstruments/reed_piano200a.py
index b924e2a..0ef5962 100644
--- a/lib/audioinstruments/reed_piano200a.py
+++ b/lib/audioinstruments/reed_piano200a.py
@@ -6,7 +6,7 @@
 NAME = "reed_piano200a"
 DISPLAY_NAME = "Reed Piano 200A"
 CATEGORIES = ("Piano",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/rhythm606.py b/lib/audioinstruments/rhythm606.py
index ee8b518..fb2ad24 100644
--- a/lib/audioinstruments/rhythm606.py
+++ b/lib/audioinstruments/rhythm606.py
@@ -6,7 +6,7 @@
 NAME = "rhythm606"
 DISPLAY_NAME = "Rhythm606"
 CATEGORIES = ("Drum",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/rhythm78.py b/lib/audioinstruments/rhythm78.py
index 7255cb1..0c98e75 100644
--- a/lib/audioinstruments/rhythm78.py
+++ b/lib/audioinstruments/rhythm78.py
@@ -6,7 +6,7 @@
 NAME = "rhythm78"
 DISPLAY_NAME = "Rhythm78"
 CATEGORIES = ("Drum",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/rhythm808.py b/lib/audioinstruments/rhythm808.py
index 93bcf06..667e2ea 100644
--- a/lib/audioinstruments/rhythm808.py
+++ b/lib/audioinstruments/rhythm808.py
@@ -6,7 +6,7 @@
 NAME = "rhythm808"
 DISPLAY_NAME = "Rhythm808"
 CATEGORIES = ("Drum",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/rhythm909.py b/lib/audioinstruments/rhythm909.py
index bd453d8..77e27ff 100644
--- a/lib/audioinstruments/rhythm909.py
+++ b/lib/audioinstruments/rhythm909.py
@@ -6,7 +6,7 @@
 NAME = "rhythm909"
 DISPLAY_NAME = "Rhythm909"
 CATEGORIES = ("Drum",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/soundfont.py b/lib/audioinstruments/soundfont.py
index bfb03f3..05d5f09 100644
--- a/lib/audioinstruments/soundfont.py
+++ b/lib/audioinstruments/soundfont.py
@@ -6,7 +6,7 @@
 NAME = "soundfont"
 DISPLAY_NAME = "SoundFont"
 CATEGORIES = ("Sampler",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/soundfont_drums.py b/lib/audioinstruments/soundfont_drums.py
index a355743..3f291d6 100644
--- a/lib/audioinstruments/soundfont_drums.py
+++ b/lib/audioinstruments/soundfont_drums.py
@@ -6,7 +6,7 @@
 NAME = "soundfont_drums"
 DISPLAY_NAME = "SoundFont Drums"
 CATEGORIES = ("Drum", "Sampler")
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/state_variable_mono.py b/lib/audioinstruments/state_variable_mono.py
index 6737b00..ba36e26 100644
--- a/lib/audioinstruments/state_variable_mono.py
+++ b/lib/audioinstruments/state_variable_mono.py
@@ -6,7 +6,7 @@
 NAME = "state_variable_mono"
 DISPLAY_NAME = "StateVariableMono"
 CATEGORIES = ("Synth",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/string_ensemble.py b/lib/audioinstruments/string_ensemble.py
index aa1ef99..4284252 100644
--- a/lib/audioinstruments/string_ensemble.py
+++ b/lib/audioinstruments/string_ensemble.py
@@ -6,7 +6,7 @@
 NAME = "string_ensemble"
 DISPLAY_NAME = "String Ensemble"
 CATEGORIES = ("Synth",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/tonewheel3.py b/lib/audioinstruments/tonewheel3.py
index 7e37cce..e1f10b4 100644
--- a/lib/audioinstruments/tonewheel3.py
+++ b/lib/audioinstruments/tonewheel3.py
@@ -6,7 +6,7 @@
 NAME = "tonewheel3"
 DISPLAY_NAME = "Tonewheel3"
 CATEGORIES = ("Synth",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/vocoder330.py b/lib/audioinstruments/vocoder330.py
index 2f417c8..75802ef 100644
--- a/lib/audioinstruments/vocoder330.py
+++ b/lib/audioinstruments/vocoder330.py
@@ -6,7 +6,7 @@
 NAME = "vocoder330"
 DISPLAY_NAME = "Vocoder330"
 CATEGORIES = ("Synth",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (
diff --git a/lib/audioinstruments/west_coast_synth.py b/lib/audioinstruments/west_coast_synth.py
index fa76c6f..d7fb10d 100644
--- a/lib/audioinstruments/west_coast_synth.py
+++ b/lib/audioinstruments/west_coast_synth.py
@@ -6,7 +6,7 @@
 NAME = "west_coast_synth"
 DISPLAY_NAME = "WestCoastSynth"
 CATEGORIES = ("Synth",)
-VERSION = "0.5.1.dev3"
+VERSION = "0.5.1.dev4"
 VENDOR = "PyDevices"
 
 MACRO_LABELS = (