diff --git a/crates/app/src/model.rs b/crates/app/src/model.rs
index 18c6d61f..ad036139 100644
--- a/crates/app/src/model.rs
+++ b/crates/app/src/model.rs
@@ -6,27 +6,21 @@ pub struct App {
     pub jack:  Jack,
     /// Port handles
     pub ports: std::collections::BTreeMap<u32, Port<Unowned>>,
-    /// Source of time
-    pub clock: Clock,
     /// Display size
     pub size: Measure<TuiOut>,
     /// Performance counter
     pub perf: PerfModel,
 
     // View and input definition
-    pub config:   Configuration,
-    /// Undo history
-    pub history:  Vec<AppCommand>,
-    // Dialog overlay
-    pub dialog:   Option<Dialog>,
-    /// Browses external resources, such as directories
-    pub browser:  Option<Browser>,
-    /// Contains all clips in the project
-    pub pool:     Option<Pool>,
-    /// Contains the currently edited MIDI clip
-    pub editor:   Option<MidiEditor>,
+    pub config:  Configuration,
     /// Contains the currently edited musical arrangement
-    pub arranger: Arrangement,
+    pub project: Arrangement,
+    /// Undo history
+    pub history: Vec<AppCommand>,
+    // Dialog overlay
+    pub dialog:  Option<Dialog>,
+    /// Contains the currently edited MIDI clip
+    pub editor:  Option<MidiEditor>,
 
     // Cache of formatted strings
     pub view_cache: Arc<RwLock<ViewCache>>,
@@ -34,11 +28,12 @@ pub struct App {
     pub color: ItemTheme,
 }
 
-has!(Option<Selection>: |self: App|self.arrangement.selected);
-has!(Vec<JackMidiIn>:   |self: App|self.arrangement.midi_ins);
-has!(Vec<JackMidiOut>:  |self: App|self.arrangement.midi_outs);
-has!(Vec<Scene>:        |self: App|self.arrangement.scenes);
-has!(Vec<Track>:        |self: App|self.arrangement.tracks);
+has!(Option<Selection>: |self: App|self.project.selected);
+has!(Vec<JackMidiIn>:   |self: App|self.project.midi_ins);
+has!(Vec<JackMidiOut>:  |self: App|self.project.midi_outs);
+has!(Vec<Scene>:        |self: App|self.project.scenes);
+has!(Vec<Track>:        |self: App|self.project.tracks);
+has!(Clock:             |self: App|self.project.clock);
 
 impl App {
     pub fn toggle_dialog (&mut self, dialog: Option<Dialog>) {
@@ -67,11 +62,85 @@ impl App {
     }
     pub(crate) fn device_add (&mut self, index: usize) -> Usually<()> {
         match index {
-            0 => self.arrangement.device_add_sampler(),
-            1 => self.arrangement.device_add_lv2(),
+            0 => self.device_add_sampler(),
+            1 => self.device_add_lv2(),
             _ => unreachable!(),
         }
     }
+    fn device_add_lv2 (&mut self) -> Usually<()> {
+        todo!();
+        Ok(())
+    }
+    fn device_add_sampler (&mut self, jack: &Jack) -> Usually<usize> {
+        let name = jack.with_client(|c|c.name().to_string());
+        let midi = self.track().expect("no active track").sequencer.midi_outs[0].name();
+        let sampler = if let Ok(sampler) = Sampler::new(
+            jack,
+            &format!("{}/Sampler", Has::<Track>::get(self).name),
+            &[PortConnect::exact(format!("{name}:{midi}"))],
+            &[&[], &[]],
+            &[&[], &[]]
+        ) {
+            self.dialog = None;
+            Device::Sampler(sampler)
+        } else {
+            self.dialog = Some(Dialog::Message(Message::FailedToAddDevice));
+            return Err("failed to add device".into())
+        };
+        Has::<Track>::get_mut(self).expect("no active track").devices.push(sampler);
+        Ok(())
+    }
+    // Create new clip in pool when entering empty cell
+    fn clip_auto_create (&mut self) -> Option<Arc<RwLock<MidiClip>>> {
+        if let Some(pool) = Has::<Option<Pool>>::get(self)
+            && let Some(Selection::TrackClip { track, scene }) = self.get()
+            && let Some(scene) = Has::<Vec<Scene>>::get_mut(self).get_mut(*scene)
+            && let Some(slot)  = scene.clips.get_mut(*track)
+            && slot.is_none()
+            && let Some(track) = Has::<Vec<Track>>::get_mut(self).get_mut(*track)
+        {
+            let (index, mut clip) = pool.add_new_clip();
+            // autocolor: new clip colors from scene and track color
+            let color = track.color.base.mix(scene.color.base, 0.5);
+            clip.write().unwrap().color = ItemColor::random_near(color, 0.2).into();
+            if let Some(ref mut editor) = Has::<Option<MidiEditor>>::get_mut(self) {
+                editor.set_clip(Some(&clip));
+            }
+            *slot = Some(clip.clone());
+            Some(clip)
+        } else {
+            None
+        }
+    }
+}
+
+#[cfg(all(feature = "pool", feature = "editor"))]
+pub trait AutoRemove:
+    Has<Vec<Scene>> +
+    Has<Vec<Track>> +
+    Has<Option<MidiEditor>> +
+    Has<Option<Selection>> +
+    Has<Option<Pool>> +
+    Send + Sync
+{
+    // Remove clip from arrangement when exiting empty clip editor
+    fn clip_auto_remove (&mut self) {
+        if let Some(ref mut pool) = Has::<Option<Pool>>::get(self)
+            && let Some(Selection::TrackClip { track, scene }) = self.get()
+            && let Some(scene) = Has::<Vec<Scene>>::get_mut(self).get_mut(*scene)
+            && let Some(slot) = scene.clips.get_mut(*track)
+            && let Some(clip) = slot.as_mut()
+        {
+            let mut swapped = None;
+            if clip.read().unwrap().count_midi_messages() == 0 {
+                std::mem::swap(&mut swapped, slot);
+            }
+            if let Some(clip) = swapped {
+                pool.delete_clip(&clip.read().unwrap());
+            }
+        }
+    }
+}
 }
 
 /// Various possible dialog overlays
@@ -81,8 +150,8 @@ pub enum Dialog {
     Menu,
     Device(usize),
     Message(Message),
-    Save,
-    Load,
+    Save(Browser),
+    Load(Browser),
     Options,
 }
 
@@ -234,27 +303,4 @@ impl App {
             0
         }
     }
-    fn device_add_lv2 (&mut self) -> Usually<()> {
-        todo!();
-        Ok(())
-    }
-    fn device_add_sampler (&mut self, jack: &Jack) -> Usually<usize> {
-        let name = jack.with_client(|c|c.name().to_string());
-        let midi = self.track().expect("no active track").sequencer.midi_outs[0].name();
-        let sampler = if let Ok(sampler) = Sampler::new(
-            jack,
-            &format!("{}/Sampler", Has::<Track>::get(self).name),
-            &[PortConnect::exact(format!("{name}:{midi}"))],
-            &[&[], &[]],
-            &[&[], &[]]
-        ) {
-            self.dialog = None;
-            Device::Sampler(sampler)
-        } else {
-            self.dialog = Some(Dialog::Message(Message::FailedToAddDevice));
-            return Err("failed to add device".into())
-        };
-        Has::<Track>::get_mut(self).expect("no active track").devices.push(sampler);
-        Ok(())
-    }
 }
diff --git a/crates/device/src/arranger/arranger_api.rs b/crates/device/src/arranger/arranger_api.rs
index bd6d4721..9034baca 100644
--- a/crates/device/src/arranger/arranger_api.rs
+++ b/crates/device/src/arranger/arranger_api.rs
@@ -6,6 +6,7 @@ impl Arrangement {
     fn _todo_arc_str_stub_ (&self) -> Arc<str> { todo!() }
     fn _todo_item_theme_stub (&self) -> ItemTheme { todo!() }
     fn _todo_opt_item_theme_stub (&self) -> Option<ItemTheme> { todo!() }
+    fn _todo_opt_selection_ (&self) -> Option<Selection> { todo!() }
 }
 
 #[tengri_proc::command(Arrangement)] 
@@ -200,117 +201,20 @@ impl ArrangementCommand {
     }
 }
 
-impl<'state> Context<'state, TrackCommand> for Arrangement {
-    fn get <'source> (&'state self, iter: &mut TokenIter<'source>) -> Option<TrackCommand> {
+impl<'state> Context<'state, MidiInputCommand> for Arrangement {
+    fn get <'source> (&'state self, iter: &mut TokenIter<'source>) -> Option<MidiInputCommand> {
         Context::get(&self, iter)
     }
 }
 
-#[tengri_proc::expose]
-impl Track {
-    fn _todo_opt_bool_stub_ (&self) -> Option<bool> { todo!() }
-    fn _todo_usize_stub_ (&self) -> usize { todo!() }
-    fn _todo_arc_str_stub_ (&self) -> Arc<str> { todo!() }
-    fn _todo_item_theme_stub (&self) -> ItemTheme { todo!() }
-}
-
-#[tengri_proc::command(Track)]
-impl TrackCommand {
-    fn set_name (track: &mut Track, mut name: Arc<str>) -> Perhaps<Self> {
-        std::mem::swap(&mut name, &mut track.name);
-        Ok(Some(Self::SetName { name }))
-    }
-    fn set_color (track: &mut Track, mut color: ItemTheme) -> Perhaps<Self> {
-        std::mem::swap(&mut color, &mut track.color);
-        Ok(Some(Self::SetColor { color }))
-    }
-    fn set_mute (track: &mut Track, value: Option<bool>) -> Perhaps<Self> {
-        todo!()
-    }
-    fn set_solo (track: &mut Track, value: Option<bool>) -> Perhaps<Self> {
-        todo!()
-    }
-    fn set_rec (track: &mut Track, value: Option<bool>) -> Perhaps<Self> {
-        let current = track.sequencer.recording;
-        let value = value.unwrap_or(!current);
-        Ok((value != current).then_some(Self::SetRec { value: Some(current) }))
-    }
-    fn set_mon (track: &mut Track, value: Option<bool>) -> Perhaps<Self> {
-        let current = track.sequencer.monitoring;
-        let value = value.unwrap_or(!current);
-        Ok((value != current).then_some(Self::SetRec { value: Some(current) }))
-    }
-    fn set_size (track: &mut Track, size: usize) -> Perhaps<Self> {
-        todo!()
-    }
-    fn set_zoom (track: &mut Track, zoom: usize) -> Perhaps<Self> {
-        todo!()
-    }
-    fn stop (track: &mut Track) -> Perhaps<Self> {
-        track.sequencer.enqueue_next(None);
-        Ok(None)
-    }
-}
-
-impl<'state> Context<'state, SceneCommand> for Arrangement {
-    fn get <'source> (&'state self, iter: &mut TokenIter<'source>) -> Option<SceneCommand> {
+impl<'state> Context<'state, MidiOutputCommand> for Arrangement {
+    fn get <'source> (&'state self, iter: &mut TokenIter<'source>) -> Option<MidiOutputCommand> {
         Context::get(&self, iter)
     }
 }
 
-impl<'state> Context<'state, ClipCommand> for Arrangement {
-    fn get <'source> (&'state self, iter: &mut TokenIter<'source>) -> Option<ClipCommand> {
+impl<'state> Context<'state, DeviceCommand> for Arrangement {
+    fn get <'source> (&'state self, iter: &mut TokenIter<'source>) -> Option<DeviceCommand> {
         Context::get(&self, iter)
     }
 }
-
-#[tengri_proc::expose]
-impl Scene {
-    fn _todo_opt_bool_stub_ (&self) -> Option<bool> { todo!() }
-    fn _todo_usize_stub_ (&self) -> usize { todo!() }
-    fn _todo_arc_str_stub_ (&self) -> Arc<str> { todo!() }
-    fn _todo_item_theme_stub (&self) -> ItemTheme { todo!() }
-}
-
-#[tengri_proc::command(Scene)]
-impl SceneCommand {
-    fn set_name (scene: &mut Scene, mut name: Arc<str>) -> Perhaps<Self> {
-        std::mem::swap(&mut scene.name, &mut name);
-        Ok(Some(Self::SetName { name }))
-    }
-    fn set_color (scene: &mut Scene, mut color: ItemTheme) -> Perhaps<Self> {
-        std::mem::swap(&mut scene.color, &mut color);
-        Ok(Some(Self::SetColor { color }))
-    }
-    fn set_size (scene: &mut Scene, size: usize) -> Perhaps<Self> {
-        todo!()
-    }
-    fn set_zoom (scene: &mut Scene, zoom: usize) -> Perhaps<Self> {
-        todo!()
-    }
-}
-
-#[tengri_proc::expose]
-impl MidiClip {
-    fn _todo_opt_bool_stub_ (&self) -> Option<bool> { todo!() }
-    fn _todo_bool_stub_ (&self) -> bool { todo!() }
-    fn _todo_usize_stub_ (&self) -> usize { todo!() }
-    fn _todo_arc_str_stub_ (&self) -> Arc<str> { todo!() }
-    fn _todo_item_theme_stub (&self) -> ItemTheme { todo!() }
-    fn _todo_opt_item_theme_stub (&self) -> Option<ItemTheme> { todo!() }
-}
-
-#[tengri_proc::command(MidiClip)]
-impl ClipCommand {
-    fn set_color (clip: &mut MidiClip, color: Option<ItemTheme>) -> Perhaps<Self> {
-        //(SetColor [t: usize, s: usize, c: ItemTheme]
-            //clip.clip_set_color(t, s, c).map(|o|Self::SetColor(t, s, o)))));
-            //("color"   [a: usize, b: usize] Some(Self::SetColor(a.unwrap(), b.unwrap(), ItemTheme::random())))
-        todo!()
-    }
-    fn set_loop (clip: &mut MidiClip, looping: Option<bool>) -> Perhaps<Self> {
-        //(SetLoop  [t: usize, s: usize, l: bool] cmd_todo!("\n\rtodo: {self:?}"))
-            //("loop"    [a: usize, b: usize, c: bool] Some(Self::SetLoop(a.unwrap(), b.unwrap(), c.unwrap())))
-        todo!()
-    }
-}
diff --git a/crates/device/src/arranger/arranger_clip.rs b/crates/device/src/arranger/arranger_clip.rs
index b5acd217..b0ad719a 100644
--- a/crates/device/src/arranger/arranger_clip.rs
+++ b/crates/device/src/arranger/arranger_clip.rs
@@ -1,5 +1,36 @@
 use crate::*;
 
+impl<'state> Context<'state, ClipCommand> for Arrangement {
+    fn get <'source> (&'state self, iter: &mut TokenIter<'source>) -> Option<ClipCommand> {
+        Context::get(&self, iter)
+    }
+}
+
+#[tengri_proc::expose]
+impl MidiClip {
+    fn _todo_opt_bool_stub_ (&self) -> Option<bool> { todo!() }
+    fn _todo_bool_stub_ (&self) -> bool { todo!() }
+    fn _todo_usize_stub_ (&self) -> usize { todo!() }
+    fn _todo_arc_str_stub_ (&self) -> Arc<str> { todo!() }
+    fn _todo_item_theme_stub (&self) -> ItemTheme { todo!() }
+    fn _todo_opt_item_theme_stub (&self) -> Option<ItemTheme> { todo!() }
+}
+
+#[tengri_proc::command(MidiClip)]
+impl ClipCommand {
+    fn set_color (clip: &mut MidiClip, color: Option<ItemTheme>) -> Perhaps<Self> {
+        //(SetColor [t: usize, s: usize, c: ItemTheme]
+            //clip.clip_set_color(t, s, c).map(|o|Self::SetColor(t, s, o)))));
+            //("color"   [a: usize, b: usize] Some(Self::SetColor(a.unwrap(), b.unwrap(), ItemTheme::random())))
+        todo!()
+    }
+    fn set_loop (clip: &mut MidiClip, looping: Option<bool>) -> Perhaps<Self> {
+        //(SetLoop  [t: usize, s: usize, l: bool] cmd_todo!("\n\rtodo: {self:?}"))
+            //("loop"    [a: usize, b: usize, c: bool] Some(Self::SetLoop(a.unwrap(), b.unwrap(), c.unwrap())))
+        todo!()
+    }
+}
+
 impl Arrangement {
 
     /// Put a clip in a slot
@@ -26,7 +57,7 @@ impl Arrangement {
 
     /// Get the active clip
     pub(crate) fn clip (&self) -> Option<Arc<RwLock<MidiClip>>> {
-        self.scene()?.clips.get(self.selected().track()?)?.clone()
+        self.scene()?.clips.get(self.selected.track()?)?.clone()
     }
 
     /// Toggle looping for the active clip
@@ -37,64 +68,3 @@ impl Arrangement {
     }
 
 }
-
-#[cfg(all(feature = "pool", feature = "editor"))]
-pub trait AutoCreate:
-    Has<Vec<Scene>> +
-    Has<Vec<Track>> +
-    Has<Option<MidiEditor>> +
-    Has<Option<Selection>> +
-    Has<Option<Pool>> +
-    Send + Sync
-{
-    // Create new clip in pool when entering empty cell
-    fn clip_auto_create (&mut self) -> Option<Arc<RwLock<MidiClip>>> {
-        if let Some(pool) = Has::<Option<Pool>>::get(self)
-            && let Some(Selection::TrackClip { track, scene }) = self.get()
-            && let Some(scene) = Has::<Vec<Scene>>::get_mut(self).get_mut(scene)
-            && let Some(slot)  = scene.clips.get_mut(track)
-            && slot.is_none()
-            && let Some(track) = Has::<Vec<Track>>::get_mut(self).get_mut(track)
-        {
-            let (index, mut clip) = pool.add_new_clip();
-            // autocolor: new clip colors from scene and track color
-            let color = track.color.base.mix(scene.color.base, 0.5);
-            clip.write().unwrap().color = ItemColor::random_near(color, 0.2).into();
-            if let Some(ref mut editor) = Has::<Option<MidiEditor>>::get_mut(self) {
-                editor.set_clip(Some(&clip));
-            }
-            *slot = Some(clip.clone());
-            Some(clip)
-        } else {
-            None
-        }
-    }
-}
-
-#[cfg(all(feature = "pool", feature = "editor"))]
-pub trait AutoRemove:
-    Has<Vec<Scene>> +
-    Has<Vec<Track>> +
-    Has<Option<MidiEditor>> +
-    Has<Option<Selection>> +
-    Has<Option<Pool>> +
-    Send + Sync
-{
-    // Remove clip from arrangement when exiting empty clip editor
-    fn clip_auto_remove (&mut self) {
-        if let Some(ref mut pool) = Has::<Option<Pool>>::get(self)
-            && let Some(Selection::TrackClip { track, scene }) = self.get()
-            && let Some(scene) = Has::<Vec<Scene>>::get_mut(self).get_mut(scene)
-            && let Some(slot) = scene.clips.get_mut(track)
-            && let Some(clip) = slot.as_mut()
-        {
-            let mut swapped = None;
-            if clip.read().unwrap().count_midi_messages() == 0 {
-                std::mem::swap(&mut swapped, slot);
-            }
-            if let Some(clip) = swapped {
-                pool.delete_clip(&clip.read().unwrap());
-            }
-        }
-    }
-}
diff --git a/crates/device/src/arranger/arranger_model.rs b/crates/device/src/arranger/arranger_model.rs
index e12e73d1..d2f3246c 100644
--- a/crates/device/src/arranger/arranger_model.rs
+++ b/crates/device/src/arranger/arranger_model.rs
@@ -6,6 +6,10 @@ pub struct Arrangement {
     pub name:         Arc<str>,
     /// Base color.
     pub color:        ItemTheme,
+    /// Jack client handle
+    pub jack:         Jack,
+    /// Source of time
+    pub clock:        Clock,
     /// List of global midi inputs
     pub midi_ins:     Vec<JackMidiIn>,
     /// List of global midi outputs
@@ -35,8 +39,8 @@ pub struct Arrangement {
     pub arranger:     Arc<RwLock<Buffer>>,
     /// Display size
     pub size:         Measure<TuiOut>,
-    /// Jack client handle
-    pub jack:         Jack,
+    /// Contains all clips in arrangement
+    pub pool:         Pool,
 }
 
 has!(Option<Selection>: |self: Arrangement|self.selected);
@@ -45,6 +49,7 @@ has!(Vec<JackMidiOut>:  |self: Arrangement|self.midi_outs);
 has!(Vec<Scene>:        |self: Arrangement|self.scenes);
 has!(Vec<Track>:        |self: Arrangement|self.tracks);
 has!(Jack:              |self: Arrangement|self.jack);
+has!(Clock:             |self: Arrangement|self.clock);
 
 impl Arrangement {
     /// Width of display
@@ -57,7 +62,8 @@ impl Arrangement {
     }
     /// Width taken by all tracks.
     pub(crate) fn w_tracks (&self) -> u16 {
-        self.tracks_with_sizes().last().map(|(_, _, _, x)|x as u16).unwrap_or(0)
+        self.tracks_with_sizes(&self.selected, None).last()
+            .map(|(_, _, _, x)|x as u16).unwrap_or(0)
     }
     /// Width available to display tracks.
     pub(crate) fn w_tracks_area (&self, is_editing: bool) -> u16 {
@@ -114,3 +120,15 @@ impl Arrangement {
         //1 + self.devices_with_sizes().last().map(|(_, _, _, _, y)|y as u16).unwrap_or(0)
     }
 }
+
+#[cfg(feature = "sampler")]
+impl Arrangement {
+    /// Get the first sampler of the active track
+    pub fn sampler (&self) -> Option<&Sampler> {
+        self.track().map(|t|t.sampler(0)).flatten()
+    }
+    /// Get the first sampler of the active track
+    pub fn sampler_mut (&mut self) -> Option<&mut Sampler> {
+        self.track_mut().map(|t|t.sampler_mut(0)).flatten()
+    }
+}
diff --git a/crates/device/src/arranger/arranger_scene.rs b/crates/device/src/arranger/arranger_scene.rs
index a217d43e..209d5397 100644
--- a/crates/device/src/arranger/arranger_scene.rs
+++ b/crates/device/src/arranger/arranger_scene.rs
@@ -1,10 +1,42 @@
 use crate::*;
 
+impl<'state> Context<'state, SceneCommand> for Arrangement {
+    fn get <'source> (&'state self, iter: &mut TokenIter<'source>) -> Option<SceneCommand> {
+        Context::get(&self, iter)
+    }
+}
+
+#[tengri_proc::expose]
+impl Scene {
+    fn _todo_opt_bool_stub_ (&self) -> Option<bool> { todo!() }
+    fn _todo_usize_stub_ (&self) -> usize { todo!() }
+    fn _todo_arc_str_stub_ (&self) -> Arc<str> { todo!() }
+    fn _todo_item_theme_stub (&self) -> ItemTheme { todo!() }
+}
+
+#[tengri_proc::command(Scene)]
+impl SceneCommand {
+    fn set_name (scene: &mut Scene, mut name: Arc<str>) -> Perhaps<Self> {
+        std::mem::swap(&mut scene.name, &mut name);
+        Ok(Some(Self::SetName { name }))
+    }
+    fn set_color (scene: &mut Scene, mut color: ItemTheme) -> Perhaps<Self> {
+        std::mem::swap(&mut scene.color, &mut color);
+        Ok(Some(Self::SetColor { color }))
+    }
+    fn set_size (scene: &mut Scene, size: usize) -> Perhaps<Self> {
+        todo!()
+    }
+    fn set_zoom (scene: &mut Scene, zoom: usize) -> Perhaps<Self> {
+        todo!()
+    }
+}
+
 impl<T: Has<Option<Scene>> + Send + Sync> HasScene for T {}
 
 pub trait HasScene: Has<Option<Scene>> + Send + Sync {
-    fn scene (&self) -> &Option<Scene> {
-        Has::<Option<Scene>>::get(self)
+    fn scene (&self) -> Option<&Scene> {
+        Has::<Option<Scene>>::get(self).as_ref()
     }
     fn scene_mut (&mut self) -> &mut Option<Scene> {
         Has::<Option<Scene>>::get_mut(self)
diff --git a/crates/device/src/arranger/arranger_select.rs b/crates/device/src/arranger/arranger_select.rs
index 2ef03033..8330faf2 100644
--- a/crates/device/src/arranger/arranger_select.rs
+++ b/crates/device/src/arranger/arranger_select.rs
@@ -13,9 +13,9 @@ pub trait HasSelection: Has<Selection> {
 
 impl Has<Option<Track>> for Arrangement {
     fn get (&self) -> &Option<Track> {
-        Has::<Option<Selection>>::get(self)
-            .and_then(|selection|selection.track())
-            .and_then(|index|Has::<Vec<Track>>::get(self).get(index))
+        let selection: Selection = Has::<Option<Track>>::get(self)?;
+        let index: Option<usize> = selection.track()?;
+        let track: Track = Has::<Vec<Track>>::get(self).get(index)?;
     }
     fn get_mut (&mut self) -> &mut Option<Track> {
         Has::<Option<Selection>>::get(self)
@@ -33,7 +33,7 @@ impl Has<Option<Scene>> for Arrangement {
     fn get_mut (&mut self) -> &mut Option<Scene> {
         Has::<Option<Selection>>::get(self)
             .and_then(|selection|selection.track())
-            .and_then(|index|Has::<Vec<Scene>>::get_mut(self).get_mut(index))
+            .and_then(|index|Has::<Vec<Scene>>::get_mut(self).get_mut(index).as_deref())
     }
 }
 
diff --git a/crates/device/src/arranger/arranger_track.rs b/crates/device/src/arranger/arranger_track.rs
index 41cb5bf1..26449380 100644
--- a/crates/device/src/arranger/arranger_track.rs
+++ b/crates/device/src/arranger/arranger_track.rs
@@ -1,5 +1,57 @@
 use crate::*;
 
+impl<'state> Context<'state, TrackCommand> for Arrangement {
+    fn get <'source> (&'state self, iter: &mut TokenIter<'source>) -> Option<TrackCommand> {
+        Context::get(&self, iter)
+    }
+}
+
+#[tengri_proc::expose]
+impl Track {
+    fn _todo_opt_bool_stub_ (&self) -> Option<bool> { todo!() }
+    fn _todo_usize_stub_ (&self) -> usize { todo!() }
+    fn _todo_arc_str_stub_ (&self) -> Arc<str> { todo!() }
+    fn _todo_item_theme_stub (&self) -> ItemTheme { todo!() }
+}
+
+#[tengri_proc::command(Track)]
+impl TrackCommand {
+    fn set_name (track: &mut Track, mut name: Arc<str>) -> Perhaps<Self> {
+        std::mem::swap(&mut name, &mut track.name);
+        Ok(Some(Self::SetName { name }))
+    }
+    fn set_color (track: &mut Track, mut color: ItemTheme) -> Perhaps<Self> {
+        std::mem::swap(&mut color, &mut track.color);
+        Ok(Some(Self::SetColor { color }))
+    }
+    fn set_mute (track: &mut Track, value: Option<bool>) -> Perhaps<Self> {
+        todo!()
+    }
+    fn set_solo (track: &mut Track, value: Option<bool>) -> Perhaps<Self> {
+        todo!()
+    }
+    fn set_rec (track: &mut Track, value: Option<bool>) -> Perhaps<Self> {
+        let current = track.sequencer.recording;
+        let value = value.unwrap_or(!current);
+        Ok((value != current).then_some(Self::SetRec { value: Some(current) }))
+    }
+    fn set_mon (track: &mut Track, value: Option<bool>) -> Perhaps<Self> {
+        let current = track.sequencer.monitoring;
+        let value = value.unwrap_or(!current);
+        Ok((value != current).then_some(Self::SetRec { value: Some(current) }))
+    }
+    fn set_size (track: &mut Track, size: usize) -> Perhaps<Self> {
+        todo!()
+    }
+    fn set_zoom (track: &mut Track, zoom: usize) -> Perhaps<Self> {
+        todo!()
+    }
+    fn stop (track: &mut Track) -> Perhaps<Self> {
+        track.sequencer.enqueue_next(None);
+        Ok(None)
+    }
+}
+
 #[derive(Debug, Default)]
 pub struct Track {
     /// Name of track
@@ -97,77 +149,6 @@ impl Track {
     }
 }
 
-impl<T: Has<Vec<Track>> + Send + Sync> HasTracks for T {}
-
-pub trait HasTracks: Has<Vec<Track>> + Send + Sync {
-    fn tracks (&self) -> &Vec<Track> {
-        Has::<Vec<Track>>::get(self)
-    }
-    fn tracks_mut (&mut self) -> &mut Vec<Track> {
-        Has::<Vec<Track>>::get_mut(self)
-    }
-    /// Run audio callbacks for every track and every device
-    fn tracks_render (&mut self, client: &Client, scope: &ProcessScope) -> Control {
-        for track in self.tracks_mut().iter_mut() {
-            if Control::Quit == PlayerAudio(
-                track.sequencer_mut(), &mut self.note_buf, &mut self.midi_buf
-            ).process(client, scope) {
-                return Control::Quit
-            }
-            for device in track.devices.iter_mut() {
-                if Control::Quit == DeviceAudio(device).process(client, scope) {
-                    return Control::Quit
-                }
-            }
-        }
-        Control::Continue
-    }
-    fn track_longest_name (&self) -> usize {
-        self.tracks().iter().map(|s|s.name.len()).fold(0, usize::max)
-    }
-    /// Stop all playing clips
-    fn tracks_stop_all (&mut self) {
-        for track in self.tracks_mut().iter_mut() {
-            track.sequencer.enqueue_next(None);
-        }
-    }
-    /// Stop all playing clips
-    fn tracks_launch (&mut self, clips: Option<Vec<Option<Arc<RwLock<MidiClip>>>>>) {
-        if let Some(clips) = clips {
-            for (clip, track) in clips.iter().zip(self.tracks_mut()) {
-                track.sequencer.enqueue_next(clip);
-            }
-        } else {
-            for track in self.tracks_mut().iter_mut() {
-                track.sequencer.enqueue_next(None);
-            }
-        }
-    }
-    /// Iterate over tracks with their corresponding sizes.
-    fn tracks_with_sizes (
-        &self,
-        selection:    &Option<Selection>,
-        editor_width: Option<usize>
-    ) -> impl TracksSizes<'_> {
-        let mut x = 0;
-        let active_track = if let Some(width) = editor_width && let Some(selection) = selection {
-            selection.track()
-        } else {
-            None
-        };
-        self.tracks().iter().enumerate().map(move |(index, track)|{
-            let width = active_track
-                .and_then(|_|editor_width)
-                .unwrap_or(track.width.max(8));
-            let data = (index, track, x, x + width);
-            x += width + Self::TRACK_SPACING;
-            data
-        })
-    }
-    /// Spacing between tracks.
-    const TRACK_SPACING: usize = 0;
-}
-
 impl<T: Has<Option<Track>> + Send + Sync> HasTrack for T {}
 
 pub trait HasTrack: Has<Option<Track>> + Send + Sync {
@@ -178,116 +159,3 @@ pub trait HasTrack: Has<Option<Track>> + Send + Sync {
         Has::<Option<Track>>::get_mut(self).as_mut()
     }
 }
-
-impl<'a> ArrangerView<'a> {
-    pub(crate) fn tracks_with_sizes_scrolled (&'a self)
-        -> impl TracksSizes<'a>
-    {
-        self.arrangement
-            .tracks_with_sizes(&self.arrangement.selected, self.is_editing.then_some(20/*FIXME*/))
-            .map_while(move|(t, track, x1, x2)|{
-                (self.width_mid > x2 as u16).then_some((t, track, x1, x2))
-            })
-    }
-}
-
-pub(crate) fn per_track_top <'a, T: Content<TuiOut> + 'a, U: TracksSizes<'a>> (
-    width:    u16,
-    tracks:   impl Fn() -> U + Send + Sync + 'a,
-    callback: impl Fn(usize, &'a Track)->T + Send + Sync + 'a
-) -> impl Content<TuiOut> + 'a {
-    Align::x(Tui::bg(Reset, Map::new(tracks,
-        move|(index, track, x1, x2): (usize, &'a Track, usize, usize), _|{
-            let width = (x2 - x1) as u16;
-            map_east(x1 as u16, width, Fixed::x(width, Tui::fg_bg(
-                track.color.lightest.rgb,
-                track.color.base.rgb,
-                callback(index, track))))})))
-}
-
-pub(crate) fn per_track <'a, T: Content<TuiOut> + 'a, U: TracksSizes<'a>> (
-    width:    u16,
-    tracks:   impl Fn() -> U + Send + Sync + 'a,
-    callback: impl Fn(usize, &'a Track)->T + Send + Sync + 'a
-) -> impl Content<TuiOut> + 'a {
-    per_track_top(
-        width,
-        tracks,
-        move|index, track|Fill::y(Align::y(callback(index, track)))
-    )
-}
-
-impl<T: HasTracks + HasScenes + HasClock + HasJack> AddTrack for T {}
-
-pub trait AddTrack: HasTracks + HasScenes + HasClock + HasJack {
-    /// Add multiple tracks
-    fn tracks_add (
-        &mut self,
-        count: usize,
-        width: Option<usize>,
-        mins:  &[PortConnect],
-        mouts: &[PortConnect],
-    ) -> Usually<()> {
-        let jack = self.jack().clone();
-        let track_color_1 = ItemColor::random();
-        let track_color_2 = ItemColor::random();
-        for i in 0..count {
-            let color = track_color_1.mix(track_color_2, i as f32 / count as f32).into();
-            let mut track = self.track_add(None, Some(color), mins, mouts)?.1;
-            if let Some(width) = width {
-                track.width = width;
-            }
-        }
-        Ok(())
-    }
-
-    /// Add a track
-    fn track_add (
-        &mut self,
-        name:  Option<&str>,
-        color: Option<ItemTheme>,
-        mins:  &[PortConnect],
-        mouts: &[PortConnect],
-    ) -> Usually<(usize, &mut Track)> {
-        self.track_last += 1;
-        let name: Arc<str> = name.map_or_else(
-            ||format!("Track{:02}", self.track_last).into(),
-            |x|x.to_string().into()
-        );
-        let mut track = Track {
-            width:  (name.len() + 2).max(12),
-            color:  color.unwrap_or_else(ItemTheme::random),
-            sequencer: Sequencer::new(
-                &format!("{name}"),
-                self.jack(),
-                Some(self.clock()),
-                None,
-                mins,
-                mouts
-            )?,
-            name,
-            ..Default::default()
-        };
-        self.tracks_mut().push(track);
-        let len = self.tracks().len();
-        let index = len - 1;
-        for scene in self.scenes_mut().iter_mut() {
-            while scene.clips.len() < len {
-                scene.clips.push(None);
-            }
-        }
-        Ok((index, &mut self.tracks_mut()[index]))
-    }
-}
-
-#[cfg(feature = "sampler")]
-impl Arrangement {
-    /// Get the first sampler of the active track
-    pub fn sampler (&self) -> Option<&Sampler> {
-        self.track().map(|t|t.sampler(0)).flatten()
-    }
-    /// Get the first sampler of the active track
-    pub fn sampler_mut (&mut self) -> Option<&mut Sampler> {
-        self.track_mut().map(|t|t.sampler_mut(0)).flatten()
-    }
-}
diff --git a/crates/device/src/arranger/arranger_tracks.rs b/crates/device/src/arranger/arranger_tracks.rs
index e69de29b..7863a9e7 100644
--- a/crates/device/src/arranger/arranger_tracks.rs
+++ b/crates/device/src/arranger/arranger_tracks.rs
@@ -0,0 +1,145 @@
+use crate::*;
+
+impl<T: Has<Vec<Track>> + Send + Sync> HasTracks for T {}
+
+pub trait HasTracks: Has<Vec<Track>> + Send + Sync {
+    fn tracks (&self) -> &Vec<Track> {
+        Has::<Vec<Track>>::get(self)
+    }
+    fn tracks_mut (&mut self) -> &mut Vec<Track> {
+        Has::<Vec<Track>>::get_mut(self)
+    }
+    /// Run audio callbacks for every track and every device
+    fn process_tracks (&mut self, client: &Client, scope: &ProcessScope) -> Control {
+        for track in self.tracks_mut().iter_mut() {
+            if Control::Quit == Audio::process(&mut track.sequencer, client, scope) {
+                return Control::Quit
+            }
+            for device in track.devices.iter_mut() {
+                if Control::Quit == DeviceAudio(device).process(client, scope) {
+                    return Control::Quit
+                }
+            }
+        }
+        Control::Continue
+    }
+    fn track_longest_name (&self) -> usize {
+        self.tracks().iter().map(|s|s.name.len()).fold(0, usize::max)
+    }
+    /// Stop all playing clips
+    fn tracks_stop_all (&mut self) {
+        for track in self.tracks_mut().iter_mut() {
+            track.sequencer.enqueue_next(None);
+        }
+    }
+    /// Stop all playing clips
+    fn tracks_launch (&mut self, clips: Option<Vec<Option<Arc<RwLock<MidiClip>>>>>) {
+        if let Some(clips) = clips {
+            for (clip, track) in clips.iter().zip(self.tracks_mut()) {
+                track.sequencer.enqueue_next(clip.as_ref());
+            }
+        } else {
+            for track in self.tracks_mut().iter_mut() {
+                track.sequencer.enqueue_next(None);
+            }
+        }
+    }
+    /// Iterate over tracks with their corresponding sizes.
+    fn tracks_with_sizes (
+        &self,
+        selection:    &Option<Selection>,
+        editor_width: Option<usize>
+    ) -> impl TracksSizes<'_> {
+        let mut x = 0;
+        let active_track = if let Some(width) = editor_width && let Some(selection) = selection {
+            selection.track()
+        } else {
+            None
+        };
+        self.tracks().iter().enumerate().map(move |(index, track)|{
+            let width = active_track
+                .and_then(|_|editor_width)
+                .unwrap_or(track.width.max(8));
+            let data = (index, track, x, x + width);
+            x += width + Self::TRACK_SPACING;
+            data
+        })
+    }
+    /// Spacing between tracks.
+    const TRACK_SPACING: usize = 0;
+}
+
+impl<'a> ArrangerView<'a> {
+    pub(crate) fn tracks_with_sizes_scrolled (&'a self)
+        -> impl TracksSizes<'a>
+    {
+        self.arrangement
+            .tracks_with_sizes(&self.arrangement.selected, self.is_editing.then_some(20/*FIXME*/))
+            .map_while(move|(t, track, x1, x2)|{
+                (self.width_mid > x2 as u16).then_some((t, track, x1, x2))
+            })
+    }
+}
+
+impl<T: HasTracks + HasScenes + HasClock + HasJack> AddTrack for T {}
+
+pub trait AddTrack: HasTracks + HasScenes + HasClock + HasJack {
+    /// Add multiple tracks
+    fn tracks_add (
+        &mut self,
+        count: usize,
+        width: Option<usize>,
+        mins:  &[PortConnect],
+        mouts: &[PortConnect],
+    ) -> Usually<()> {
+        let jack = self.jack().clone();
+        let track_color_1 = ItemColor::random();
+        let track_color_2 = ItemColor::random();
+        for i in 0..count {
+            let color = track_color_1.mix(track_color_2, i as f32 / count as f32).into();
+            let mut track = self.track_add(None, Some(color), mins, mouts)?.1;
+            if let Some(width) = width {
+                track.width = width;
+            }
+        }
+        Ok(())
+    }
+
+    /// Add a track
+    fn track_add (
+        &mut self,
+        name:  Option<&str>,
+        color: Option<ItemTheme>,
+        mins:  &[PortConnect],
+        mouts: &[PortConnect],
+    ) -> Usually<(usize, &mut Track)> {
+        self.track_last += 1;
+        let name: Arc<str> = name.map_or_else(
+            ||format!("Track{:02}", self.track_last).into(),
+            |x|x.to_string().into()
+        );
+        let mut track = Track {
+            width:  (name.len() + 2).max(12),
+            color:  color.unwrap_or_else(ItemTheme::random),
+            sequencer: Sequencer::new(
+                &format!("{name}"),
+                self.jack(),
+                Some(self.clock()),
+                None,
+                mins,
+                mouts
+            )?,
+            name,
+            ..Default::default()
+        };
+        self.tracks_mut().push(track);
+        let len = self.tracks().len();
+        let index = len - 1;
+        for scene in self.scenes_mut().iter_mut() {
+            while scene.clips.len() < len {
+                scene.clips.push(None);
+            }
+        }
+        Ok((index, &mut self.tracks_mut()[index]))
+    }
+}
diff --git a/crates/device/src/arranger/arranger_view.rs b/crates/device/src/arranger/arranger_view.rs
index e28d3362..e6213432 100644
--- a/crates/device/src/arranger/arranger_view.rs
+++ b/crates/device/src/arranger/arranger_view.rs
@@ -283,3 +283,29 @@ impl<'a> ArrangerView<'a> {
     }
 
 }
+
+pub(crate) fn per_track_top <'a, T: Content<TuiOut> + 'a, U: TracksSizes<'a>> (
+    width:    u16,
+    tracks:   impl Fn() -> U + Send + Sync + 'a,
+    callback: impl Fn(usize, &'a Track)->T + Send + Sync + 'a
+) -> impl Content<TuiOut> + 'a {
+    Align::x(Tui::bg(Reset, Map::new(tracks,
+        move|(index, track, x1, x2): (usize, &'a Track, usize, usize), _|{
+            let width = (x2 - x1) as u16;
+            map_east(x1 as u16, width, Fixed::x(width, Tui::fg_bg(
+                track.color.lightest.rgb,
+                track.color.base.rgb,
+                callback(index, track))))})))
+}
+
+pub(crate) fn per_track <'a, T: Content<TuiOut> + 'a, U: TracksSizes<'a>> (
+    width:    u16,
+    tracks:   impl Fn() -> U + Send + Sync + 'a,
+    callback: impl Fn(usize, &'a Track)->T + Send + Sync + 'a
+) -> impl Content<TuiOut> + 'a {
+    per_track_top(
+        width,
+        tracks,
+        move|index, track|Fill::y(Align::y(callback(index, track)))
+    )
+}
diff --git a/crates/device/src/clock/clock_model.rs b/crates/device/src/clock/clock_model.rs
index e9016264..c961233a 100644
--- a/crates/device/src/clock/clock_model.rs
+++ b/crates/device/src/clock/clock_model.rs
@@ -177,4 +177,25 @@ impl Clock {
     pub fn next_launch_instant (&self) -> Moment {
         Moment::from_pulse(self.timebase(), self.next_launch_pulse() as f64)
     }
+
+    /// Get index of first sample to populate.
+    ///
+    /// Greater than 0 means that the first pulse of the clip
+    /// falls somewhere in the middle of the chunk.
+    pub fn get_sample_offset (&self, scope: &ProcessScope, started: &Moment) -> usize{
+        (scope.last_frame_time() as usize).saturating_sub(
+            started.sample.get() as usize +
+            self.started.read().unwrap().as_ref().unwrap().sample.get() as usize
+        )
+    }
+
+    // Get iterator that emits sample paired with pulse.
+    //
+    // * Sample: index into output buffer at which to write MIDI event
+    // * Pulse: index into clip from which to take the MIDI event
+    //
+    // Emitted for each sample of the output buffer that corresponds to a MIDI pulse.
+    pub fn get_pulses (&self, scope: &ProcessScope, offset: usize) -> TicksIterator {
+        self.timebase().pulses_between_samples(offset, offset + scope.n_frames() as usize)
+    }
 }
diff --git a/crates/device/src/sequencer/seq_audio.rs b/crates/device/src/sequencer/seq_audio.rs
index c96b7cdc..060d833b 100644
--- a/crates/device/src/sequencer/seq_audio.rs
+++ b/crates/device/src/sequencer/seq_audio.rs
@@ -1,82 +1,45 @@
 use crate::*;
 
-/// Hosts the JACK callback for a single MIDI sequencer
-pub struct PlayerAudio<'a, T: MidiSequencer>(
-    /// Player
-    pub &'a mut T,
-    /// Note buffer
-    pub &'a mut Vec<u8>,
-    /// Note chunk buffer
-    pub &'a mut Vec<Vec<Vec<u8>>>,
-);
-
 /// JACK process callback for a sequencer's clip sequencer/recorder.
-impl<T: MidiSequencer> Audio for PlayerAudio<'_, T> {
+impl Audio for Sequencer {
     fn process (&mut self, _: &Client, scope: &ProcessScope) -> Control {
-        let model    = &mut self.0;
-        let note_buf = &mut self.1;
-        let midi_buf = &mut self.2;
-        // Clear output buffer(s)
-        model.clear(scope, midi_buf, false);
-        // Write chunk of clip to output, handle switchover
-        if model.play(scope, note_buf, midi_buf) {
-            model.switchover(scope, note_buf, midi_buf);
+        if self.clock().is_rolling() {
+            self.process_rolling(scope)
+        } else {
+            self.process_stopped(scope)
         }
-        if !model.midi_ins().is_empty() {
-            if model.recording() || model.monitoring() {
-                // Record and/or monitor input
-                model.record(scope, midi_buf)
-            } else if model.midi_outs().is_empty() && model.monitoring() {
-                // Monitor input to output
-                model.monitor(scope, midi_buf)
-            }
-        }
-        // Write to output port(s)
-        model.write(scope, midi_buf);
-        Control::Continue
     }
 }
 
-pub trait MidiSequencer: MidiRecorder + MidiPlayer + Send + Sync {}
-
-impl MidiSequencer for Sequencer {}
-
-pub trait MidiRecorder: HasClock + HasPlayClip + HasMidiIns {
-    fn notes_in (&self) -> &Arc<RwLock<[bool;128]>>;
-
-    fn recording (&self) -> bool;
-
-    fn recording_mut (&mut self) -> &mut bool;
-
-    fn toggle_record (&mut self) {
-        *self.recording_mut() = !self.recording();
+impl Sequencer {
+    fn process_rolling (&mut self, scope: &ProcessScope) -> Control {
+        self.process_clear(scope, false);
+        // Write chunk of clip to output, handle switchover
+        if self.process_playback(scope) {
+            self.process_switchover(scope);
+        }
+        // Monitor input to output
+        self.process_monitoring(scope);
+        // Record and/or monitor input
+        self.process_recording(scope);
+        // Emit contents of MIDI buffers to JACK MIDI output ports.
+        self.midi_outs_emit(scope);
+        Control::Continue
     }
-
-    fn monitoring (&self) -> bool;
-
-    fn monitoring_mut (&mut self) -> &mut bool;
-
-    fn toggle_monitor (&mut self) {
-        *self.monitoring_mut() = !self.monitoring();
+    fn process_stopped (&mut self, scope: &ProcessScope) -> Control {
+        if self.monitoring() && self.midi_ins().len() > 0 && self.midi_outs().len() > 0 {
+            self.process_monitoring(scope)
+        }
+        Control::Continue
     }
-
-    fn overdub (&self) -> bool;
-
-    fn overdub_mut (&mut self) -> &mut bool;
-
-    fn toggle_overdub (&mut self) {
-        *self.overdub_mut() = !self.overdub();
-    }
-
-    fn monitor (&mut self, scope: &ProcessScope, midi_buf: &mut Vec<Vec<Vec<u8>>>) {
-        // For highlighting keys and note repeat
-        let notes_in = self.notes_in().clone();
+    fn process_monitoring (&mut self, scope: &ProcessScope) {
+        let notes_in = self.notes_in().clone(); // For highlighting keys and note repeat
         let monitoring = self.monitoring();
-        for input in self.midi_ins_mut().iter() {
-            for (sample, event, bytes) in parse_midi_input(input.port().iter(scope)) {
+        for input in self.midi_ins.iter() {
+            for (sample, event, bytes) in input.parsed(scope) {
                 if let LiveEvent::Midi { message, .. } = event {
                     if monitoring {
-                        midi_buf[sample].push(bytes.to_vec());
+                        self.midi_buf[sample].push(bytes.to_vec());
                     }
                     // FIXME: don't lock on every event!
                     update_keys(&mut notes_in.write().unwrap(), &message);
@@ -84,28 +47,143 @@ pub trait MidiRecorder: HasClock + HasPlayClip + HasMidiIns {
             }
         }
     }
-
-    fn record (&mut self, scope: &ProcessScope, midi_buf: &mut Vec<Vec<Vec<u8>>>) {
+    /// Clear the section of the output buffer that we will be using,
+    /// emitting "all notes off" at start of buffer if requested.
+    fn process_clear (&mut self, scope: &ProcessScope, reset: bool) {
+        let n_frames = (scope.n_frames() as usize).min(self.midi_buf_mut().len());
+        for frame in &mut self.midi_buf_mut()[0..n_frames] {
+            frame.clear();
+        }
+        if reset {
+            all_notes_off(self.midi_buf_mut());
+        }
+        for port in self.midi_outs_mut().iter_mut() {
+            // Clear output buffer(s)
+            port.buffer_clear(scope, false);
+        }
+    }
+    fn process_recording (&mut self, scope: &ProcessScope) {
         if self.monitoring() {
-            self.monitor(scope, midi_buf);
+            self.monitor(scope);
         }
-        if !self.clock().is_rolling() {
-            return
-        }
-        if let Some((started, ref clip)) = self.play_clip().clone() {
-            self.record_clip(scope, started, clip, midi_buf);
+        if let Some((started, ref clip)) = self.play_clip.clone() {
+            self.record_clip(scope, started, clip);
         }
         if let Some((_start_at, _clip)) = &self.next_clip() {
             self.record_next();
         }
     }
+    fn process_playback (&mut self, scope: &ProcessScope) -> bool {
+        // If a clip is playing, write a chunk of MIDI events from it to the output buffer.
+        // If no clip is playing, prepare for switchover immediately.
+        if let Some((started, clip)) = &self.play_clip {
+            // Length of clip, to repeat or stop on end.
+            let length = clip.as_ref().map_or(0, |p|p.read().unwrap().length);
+            // Index of first sample to populate.
+            let offset = self.clock().get_sample_offset(scope, &started);
+            // Write MIDI events from clip at sample offsets corresponding to pulses.
+            for (sample, pulse) in self.clock().get_pulses(scope, offset) {
+                // If a next clip is enqueued, and we're past the end of the current one,
+                // break the loop here (FIXME count pulse correctly)
+                let past_end = if clip.is_some() { pulse >= length } else { true };
+                // Is it time for switchover?
+                if self.next_clip().is_some() && past_end {
+                    return true
+                }
+                // If there's a currently playing clip, output notes from it to buffer:
+                if let Some(ref clip) = clip {
+                    // Source clip from which the MIDI events will be taken.
+                    let clip = clip.read().unwrap();
+                    // Clip with zero length is not processed
+                    if clip.length > 0 {
+                        // Current pulse index in source clip
+                        let pulse = pulse % clip.length;
+                        // Output each MIDI event from clip at appropriate frames of output buffer:
+                        for message in clip.notes[pulse].iter() {
+                            for port in self.midi_outs.iter_mut() {
+                                port.buffer_write(sample, LiveEvent::Midi {
+                                    channel: 0.into(), /* TODO */
+                                    message: *message
+                                });
+                            }
+                        }
+                    }
+                }
+            }
+            false
+        } else {
+            true
+        }
+    }
+    /// Handle switchover from current to next playing clip.
+    fn process_switchover (&mut self, scope: &ProcessScope) {
+        let midi_buf = self.midi_buf_mut();
+        let sample0 = scope.last_frame_time() as usize;
+        //let samples = scope.n_frames() as usize;
+        if let Some((start_at, clip)) = &self.next_clip() {
+            let start  = start_at.sample.get() as usize;
+            let sample = self.clock().started.read().unwrap()
+                .as_ref().unwrap().sample.get() as usize;
+            // If it's time to switch to the next clip:
+            if start <= sample0.saturating_sub(sample) {
+                // Samples elapsed since clip was supposed to start
+                let _skipped = sample0 - start;
+                // Switch over to enqueued clip
+                let started = Moment::from_sample(self.clock().timebase(), start as f64);
+                // Launch enqueued clip
+                *self.play_clip_mut() = Some((started, clip.clone()));
+                // Unset enqueuement (TODO: where to implement looping?)
+                *self.next_clip_mut() = None;
+                // Fill in remaining ticks of chunk from next clip.
+                self.process_playback(scope);
+            }
+        }
+    }
+}
+
+pub trait HasMidiBuffers {
+    fn note_buf_mut (&mut self) -> &mut Vec<u8>;
+    fn midi_buf_mut (&mut self) -> &mut Vec<Vec<Vec<u8>>>;
+}
+
+impl HasMidiBuffers for Sequencer {
+    fn note_buf_mut (&mut self) -> &mut Vec<u8> {
+        &mut self.note_buf
+    }
+    fn midi_buf_mut (&mut self) -> &mut Vec<Vec<Vec<u8>>> {
+        &mut self.midi_buf
+    }
+}
+
+pub trait MidiMonitor: HasMidiIns + HasMidiBuffers {
+    fn notes_in (&self) -> &Arc<RwLock<[bool;128]>>;
+    fn monitoring (&self) -> bool;
+    fn monitoring_mut (&mut self) -> &mut bool;
+    fn toggle_monitor (&mut self) {
+        *self.monitoring_mut() = !self.monitoring();
+    }
+    fn monitor (&mut self, scope: &ProcessScope) {
+    }
+}
+
+pub trait MidiRecord: MidiMonitor + HasClock + HasPlayClip {
+    fn recording (&self) -> bool;
+    fn recording_mut (&mut self) -> &mut bool;
+    fn toggle_record (&mut self) {
+        *self.recording_mut() = !self.recording();
+    }
+
+    fn overdub (&self) -> bool;
+    fn overdub_mut (&mut self) -> &mut bool;
+    fn toggle_overdub (&mut self) {
+        *self.overdub_mut() = !self.overdub();
+    }
 
     fn record_clip (
         &mut self,
-        scope:     &ProcessScope,
-        started:   Moment,
-        clip:      &Option<Arc<RwLock<MidiClip>>>,
-        _midi_buf: &mut Vec<Vec<Vec<u8>>>
+        scope:   &ProcessScope,
+        started: Moment,
+        clip:    &Option<Arc<RwLock<MidiClip>>>,
     ) {
         if let Some(clip) = clip {
             let sample0    = scope.last_frame_time() as usize;
@@ -113,7 +191,7 @@ pub trait MidiRecorder: HasClock + HasPlayClip + HasMidiIns {
             let _recording = self.recording();
             let timebase   = self.clock().timebase().clone();
             let quant      = self.clock().quant.get();
-            let mut clip = clip.write().unwrap();
+            let mut clip   = clip.write().unwrap();
             let length     = clip.length;
             for input in self.midi_ins_mut().iter() {
                 for (sample, event, _bytes) in parse_midi_input(input.port().iter(scope)) {
@@ -133,173 +211,4 @@ pub trait MidiRecorder: HasClock + HasPlayClip + HasMidiIns {
     fn record_next (&mut self) {
         // TODO switch to next clip and record into it
     }
-
-}
-
-pub trait MidiPlayer: HasPlayClip + HasClock + HasMidiOuts {
-
-    fn notes_out (&self) -> &Arc<RwLock<[bool;128]>>;
-
-    /// Clear the section of the output buffer that we will be using,
-    /// emitting "all notes off" at start of buffer if requested.
-    fn clear (
-        &mut self, scope: &ProcessScope, out: &mut [Vec<Vec<u8>>], reset: bool
-    ) {
-        let n_frames = (scope.n_frames() as usize).min(out.len());
-        for frame in &mut out[0..n_frames] {
-            frame.clear();
-        }
-        if reset {
-            all_notes_off(out);
-        }
-    }
-
-    /// Output notes from clip to MIDI output ports.
-    fn play (
-        &mut self, scope: &ProcessScope, note_buf: &mut Vec<u8>, out: &mut [Vec<Vec<u8>>]
-    ) -> bool {
-        if !self.clock().is_rolling() {
-            return false
-        }
-        // If a clip is playing, write a chunk of MIDI events from it to the output buffer.
-        // If no clip is playing, prepare for switchover immediately.
-        if let Some((started, clip)) = self.play_clip() {
-            self.play_chunk(scope, note_buf, out, started, clip)
-        } else {
-            true
-        }
-    }
-
-    fn play_chunk (
-        &self,
-        scope:    &ProcessScope,
-        note_buf: &mut Vec<u8>,
-        out:      &mut [Vec<Vec<u8>>],
-        started:  &Moment,
-        clip:     &Option<Arc<RwLock<MidiClip>>>
-    ) -> bool {
-        // Index of first sample to populate.
-        let offset = self.get_sample_offset(scope, started);
-        // Notes active during current chunk.
-        let notes  = &mut self.notes_out().write().unwrap();
-        // Length of clip.
-        let length = clip.as_ref().map_or(0, |p|p.read().unwrap().length);
-        // Write MIDI events from clip at sample offsets corresponding to pulses.
-        for (sample, pulse) in self.get_pulses(scope, offset) {
-            // If a next clip is enqueued, and we're past the end of the current one,
-            // break the loop here (FIXME count pulse correctly)
-            let past_end = if clip.is_some() { pulse >= length } else { true };
-            // Is it time for switchover?
-            if self.next_clip().is_some() && past_end {
-                return true
-            }
-            // If there's a currently playing clip, output notes from it to buffer:
-            if let Some(ref clip) = clip {
-                Self::play_pulse(clip, pulse, sample, note_buf, out, notes)
-            }
-        }
-        false
-    }
-
-    /// Get index of first sample to populate.
-    ///
-    /// Greater than 0 means that the first pulse of the clip
-    /// falls somewhere in the middle of the chunk.
-    fn get_sample_offset (&self, scope: &ProcessScope, started: &Moment) -> usize{
-        (scope.last_frame_time() as usize).saturating_sub(
-            started.sample.get() as usize +
-            self.clock().started.read().unwrap().as_ref().unwrap().sample.get() as usize
-        )
-    }
-
-    // Get iterator that emits sample paired with pulse.
-    //
-    // * Sample: index into output buffer at which to write MIDI event
-    // * Pulse: index into clip from which to take the MIDI event
-    //
-    // Emitted for each sample of the output buffer that corresponds to a MIDI pulse.
-    fn get_pulses (&self, scope: &ProcessScope, offset: usize) -> TicksIterator {
-        self.clock().timebase().pulses_between_samples(
-            offset, offset + scope.n_frames() as usize)
-    }
-
-    /// Handle switchover from current to next playing clip.
-    fn switchover (
-        &mut self, scope: &ProcessScope, note_buf: &mut Vec<u8>, out: &mut [Vec<Vec<u8>>]
-    ) {
-        if !self.clock().is_rolling() {
-            return
-        }
-        let sample0 = scope.last_frame_time() as usize;
-        //let samples = scope.n_frames() as usize;
-        if let Some((start_at, clip)) = &self.next_clip() {
-            let start  = start_at.sample.get() as usize;
-            let sample = self.clock().started.read().unwrap()
-                .as_ref().unwrap().sample.get() as usize;
-            // If it's time to switch to the next clip:
-            if start <= sample0.saturating_sub(sample) {
-                // Samples elapsed since clip was supposed to start
-                let _skipped = sample0 - start;
-                // Switch over to enqueued clip
-                let started = Moment::from_sample(self.clock().timebase(), start as f64);
-                // Launch enqueued clip
-                *self.play_clip_mut() = Some((started, clip.clone()));
-                // Unset enqueuement (TODO: where to implement looping?)
-                *self.next_clip_mut() = None;
-                // Fill in remaining ticks of chunk from next clip.
-                self.play(scope, note_buf, out);
-            }
-        }
-    }
-
-    fn play_pulse (
-        clip:   &RwLock<MidiClip>,
-        pulse:    usize,
-        sample:   usize,
-        note_buf: &mut Vec<u8>,
-        out:      &mut [Vec<Vec<u8>>],
-        notes:    &mut [bool;128]
-    ) {
-        // Source clip from which the MIDI events will be taken.
-        let clip = clip.read().unwrap();
-        // Clip with zero length is not processed
-        if clip.length > 0 {
-            // Current pulse index in source clip
-            let pulse = pulse % clip.length;
-            // Output each MIDI event from clip at appropriate frames of output buffer:
-            for message in clip.notes[pulse].iter() {
-                // Clear output buffer for this MIDI event.
-                note_buf.clear();
-                // TODO: support MIDI channels other than CH1.
-                let channel = 0.into();
-                // Serialize MIDI event into message buffer.
-                LiveEvent::Midi { channel, message: *message }
-                    .write(note_buf)
-                    .unwrap();
-                // Append serialized message to output buffer.
-                out[sample].push(note_buf.clone());
-                // Update the list of currently held notes.
-                update_keys(&mut*notes, message);
-            }
-        }
-    }
-
-    /// Write a chunk of MIDI data from the output buffer to all assigned output ports.
-    fn write (&mut self, scope: &ProcessScope, out: &[Vec<Vec<u8>>]) {
-        let samples = scope.n_frames() as usize;
-        for port in self.midi_outs_mut().iter_mut() {
-            Self::write_port(&mut port.port_mut().writer(scope), samples, out)
-        }
-    }
-
-    /// Write a chunk of MIDI data from the output buffer to an output port.
-    fn write_port (writer: &mut MidiWriter, samples: usize, out: &[Vec<Vec<u8>>]) {
-        for (time, events) in out.iter().enumerate().take(samples) {
-            for bytes in events.iter() {
-                writer.write(&RawMidi { time: time as u32, bytes }).unwrap_or_else(|_|{
-                    panic!("Failed to write MIDI data: {bytes:?}");
-                });
-            }
-        }
-    }
 }
diff --git a/crates/device/src/sequencer/seq_model.rs b/crates/device/src/sequencer/seq_model.rs
index a4dd982d..5524dc04 100644
--- a/crates/device/src/sequencer/seq_model.rs
+++ b/crates/device/src/sequencer/seq_model.rs
@@ -2,17 +2,17 @@
 use crate::*;
 
 impl<T: Has<Sequencer>> HasSequencer for T {
-    fn sequencer (&self) -> &impl MidiSequencer {
+    fn sequencer (&self) -> &Sequencer {
         self.get()
     }
-    fn sequencer_mut (&mut self) -> &mut impl MidiSequencer {
+    fn sequencer_mut (&mut self) -> &mut Sequencer {
         self.get_mut()
     }
 }
 
 pub trait HasSequencer {
-    fn sequencer (&self) -> &impl MidiSequencer;
-    fn sequencer_mut (&mut self) -> &mut impl MidiSequencer;
+    fn sequencer (&self) -> &Sequencer;
+    fn sequencer_mut (&mut self) -> &mut Sequencer;
 }
 
 /// Contains state for playing a clip
@@ -41,6 +41,8 @@ pub struct Sequencer {
     pub notes_out:  Arc<RwLock<[bool; 128]>>,
     /// MIDI output buffer
     pub note_buf:   Vec<u8>,
+    /// MIDI output buffer
+    pub midi_buf:   Vec<Vec<Vec<u8>>>,
 }
 
 impl Default for Sequencer {
@@ -55,6 +57,7 @@ impl Default for Sequencer {
             notes_in:   RwLock::new([false;128]).into(),
             notes_out:  RwLock::new([false;128]).into(),
             note_buf:   vec![0;8],
+            midi_buf:   vec![],
             reset:      true,
 
             midi_ins:   vec![],
@@ -80,14 +83,10 @@ impl Sequencer {
             midi_outs:  vec![JackMidiOut::new(jack, format!("{}/M", name.as_ref()), midi_to)?,  ],
             play_clip:  clip.map(|clip|(Moment::zero(&clock.timebase), Some(clip.clone()))),
             clock,
-            note_buf:   vec![0;8],
             reset:      true,
-            recording:  false,
-            monitoring: false,
-            overdub:    false,
-            next_clip:  None,
             notes_in:   RwLock::new([false;128]).into(),
             notes_out:  RwLock::new([false;128]).into(),
+            ..Default::default()
         })
     }
 }
@@ -106,12 +105,9 @@ has!(Clock:            |self: Sequencer|self.clock);
 has!(Vec<JackMidiIn>:  |self:Sequencer| self.midi_ins);
 has!(Vec<JackMidiOut>: |self:Sequencer| self.midi_outs);
 
-impl MidiRecorder for Sequencer {
-    fn recording (&self) -> bool {
-        self.recording
-    }
-    fn recording_mut (&mut self) -> &mut bool {
-        &mut self.recording
+impl MidiMonitor for Sequencer {
+    fn notes_in (&self) -> &Arc<RwLock<[bool; 128]>> {
+        &self.notes_in
     }
     fn monitoring (&self) -> bool {
         self.monitoring
@@ -119,21 +115,21 @@ impl MidiRecorder for Sequencer {
     fn monitoring_mut (&mut self) -> &mut bool {
         &mut self.monitoring
     }
+}
+
+impl MidiRecord for Sequencer {
+    fn recording (&self) -> bool {
+        self.recording
+    }
+    fn recording_mut (&mut self) -> &mut bool {
+        &mut self.recording
+    }
     fn overdub (&self) -> bool {
         self.overdub
     }
     fn overdub_mut (&mut self) -> &mut bool {
         &mut self.overdub
     }
-    fn notes_in (&self) -> &Arc<RwLock<[bool; 128]>> {
-        &self.notes_in
-    }
-}
-
-impl MidiPlayer for Sequencer {
-    fn notes_out (&self) -> &Arc<RwLock<[bool; 128]>> {
-        &self.notes_out
-    }
 }
 
 impl HasPlayClip for Sequencer {
diff --git a/crates/engine/src/jack/jack_port.rs b/crates/engine/src/jack/jack_port.rs
index 85136cb9..8d0d852d 100644
--- a/crates/engine/src/jack/jack_port.rs
+++ b/crates/engine/src/jack/jack_port.rs
@@ -189,7 +189,7 @@ macro_rules! impl_port {
             type Pair = $Pair;
             fn port (&self) -> &Port<$Spec> { &self.port }
         }
-        impl JackPortConnect<&str> for $Name {
+       impl JackPortConnect<&str> for $Name {
             fn connect_to (&self, to: &str) -> Usually<PortConnectStatus> {
                 self.with_client(|c|if let Some(ref port) = c.port_by_name(to.as_ref()) {
                     self.connect_to(port)
@@ -233,5 +233,3 @@ impl_port!(JackAudioIn:  AudioIn  -> AudioOut |j, n|j.register_port::<AudioIn>(n
 impl_port!(JackAudioOut: AudioOut -> AudioIn  |j, n|j.register_port::<AudioOut>(n));
 
 impl_port!(JackMidiIn:   MidiIn   -> MidiOut  |j, n|j.register_port::<MidiIn>(n));
-
-impl_port!(JackMidiOut:  MidiOut  -> MidiIn   |j, n|j.register_port::<MidiOut>(n));
diff --git a/crates/engine/src/lib.rs b/crates/engine/src/lib.rs
index e9bcf677..55b8d382 100644
--- a/crates/engine/src/lib.rs
+++ b/crates/engine/src/lib.rs
@@ -18,6 +18,16 @@ pub trait Has<T>: Send + Sync {
     fn get_mut (&mut self) -> &mut T;
 }
 
+pub trait MaybeHas<T>: Send + Sync {
+    fn get (&self) -> Option<&T>;
+}
+
+impl<T, U: Has<Option<T>>> MaybeHas<T> for U {
+    fn get (&self) -> Option<&T> {
+        Has::<Option<T>>::get(self).as_ref()
+    }
+}
+
 #[macro_export] macro_rules! has {
     ($T:ty: |$self:ident : $S:ty| $x:expr) => {
         impl Has<$T> for $S {
diff --git a/crates/engine/src/midi.rs b/crates/engine/src/midi.rs
index e6a656b0..c3588d1c 100644
--- a/crates/engine/src/midi.rs
+++ b/crates/engine/src/midi.rs
@@ -9,17 +9,9 @@ pub use ::midly::{
     live::*,
 };
 
-mod midi_in;  pub use self::midi_in::*;
-mod midi_out; pub use self::midi_out::*;
-
-/// Update notes_in array
-pub fn update_keys (keys: &mut[bool;128], message: &MidiMessage) {
-    match message {
-        MidiMessage::NoteOn  { key, .. } => { keys[key.as_int() as usize] = true; }
-        MidiMessage::NoteOff { key, .. } => { keys[key.as_int() as usize] = false; },
-        _ => {}
-    }
-}
+mod midi_in;   pub use self::midi_in::*;
+mod midi_out;  pub use self::midi_out::*;
+mod midi_hold; pub use self::midi_hold::*;
 
 /// Return boxed iterator of MIDI events
 pub fn parse_midi_input <'a> (input: ::jack::MidiIter<'a>) -> Box<dyn Iterator<Item=(usize, LiveEvent<'a>, &'a [u8])> + 'a> {
diff --git a/crates/engine/src/midi/midi_hold.rs b/crates/engine/src/midi/midi_hold.rs
new file mode 100644
index 00000000..0717e90c
--- /dev/null
+++ b/crates/engine/src/midi/midi_hold.rs
@@ -0,0 +1,10 @@
+use crate::*;
+
+/// Update notes_in array
+pub fn update_keys (keys: &mut[bool;128], message: &MidiMessage) {
+    match message {
+        MidiMessage::NoteOn  { key, .. } => { keys[key.as_int() as usize] = true; }
+        MidiMessage::NoteOff { key, .. } => { keys[key.as_int() as usize] = false; },
+        _ => {}
+    }
+}
diff --git a/crates/engine/src/midi/midi_in.rs b/crates/engine/src/midi/midi_in.rs
index 27cbd76e..027025d0 100644
--- a/crates/engine/src/midi/midi_in.rs
+++ b/crates/engine/src/midi/midi_in.rs
@@ -1,5 +1,11 @@
 use crate::*;
 
+impl JackMidiIn {
+    pub fn parsed <'a> (&'a self, scope: &'a ProcessScope) -> impl Iterator<Item=(usize, LiveEvent<'a>, &'a [u8])> {
+        parse_midi_input(self.port().iter(scope))
+    }
+}
+
 #[tengri_proc::command(JackMidiIn)]
 impl MidiInputCommand {
 }
diff --git a/crates/engine/src/midi/midi_out.rs b/crates/engine/src/midi/midi_out.rs
index 89a22296..514f6487 100644
--- a/crates/engine/src/midi/midi_out.rs
+++ b/crates/engine/src/midi/midi_out.rs
@@ -1,5 +1,151 @@
 use crate::*;
 
+#[derive(Debug)] pub struct JackMidiOut {
+    /// Handle to JACK client, for receiving reconnect events.
+    jack: Jack,
+    /// Port name
+    name: Arc<str>,
+    /// Port handle.
+    port: Port<MidiOut>,
+    /// List of ports to connect to.
+    conn: Vec<PortConnect>,
+    /// List of currently held notes.
+    held: Arc<RwLock<[bool;128]>>,
+    /// Buffer
+    note_buffer: Vec<u8>,
+    /// Buffer
+    output_buffer: Vec<Vec<Vec<u8>>>,
+}
+
+has!(Jack: |self: JackMidiOut|self.jack);
+
+impl JackMidiOut {
+    pub fn new (jack: &Jack, name: impl AsRef<str>, connect: &[PortConnect])
+        -> Usually<Self>
+    {
+        let jack = jack.clone();
+        let port = jack.register_port::<MidiOut>(name.as_ref())?;
+        let name = name.as_ref().into();
+        let conn = connect.to_vec();
+        let port = Self {
+            jack,
+            port,
+            name,
+            conn,
+            held: Arc::new([false;128].into()),
+            note_buffer: vec![0;8],
+            output_buffer: vec![vec![];65536],
+        };
+        port.connect_to_matching()?;
+        Ok(port)
+    }
+    pub fn name (&self) -> &Arc<str> {
+        &self.name
+    }
+    pub fn port (&self) -> &Port<MidiOut> {
+        &self.port
+    }
+    pub fn port_mut (&mut self) -> &mut Port<MidiOut> {
+        &mut self.port
+    }
+    pub fn into_port (self) -> Port<MidiOut> {
+        self.port
+    }
+    pub fn close (self) -> Usually<()> {
+        let Self { jack, port, .. } = self;
+        Ok(jack.with_client(|client|client.unregister_port(port))?)
+    }
+    /// Clear the section of the output buffer that we will be using,
+    /// emitting "all notes off" at start of buffer if requested.
+    pub fn buffer_clear (&mut self, scope: &ProcessScope, reset: bool) {
+        let n_frames = (scope.n_frames() as usize).min(self.output_buffer.len());
+        for frame in &mut self.output_buffer[0..n_frames] {
+            frame.clear();
+        }
+        if reset {
+            all_notes_off(&mut self.output_buffer);
+        }
+    }
+    /// Write a note to the output buffer
+    pub fn buffer_write <'a> (
+        &'a mut self,
+        sample: usize,
+        event:  LiveEvent,
+    ) {
+        self.note_buffer.fill(0);
+        event.write(&mut self.note_buffer).expect("failed to serialize MIDI event");
+        self.output_buffer[sample].push(self.note_buffer.clone());
+        // Update the list of currently held notes.
+        if let LiveEvent::Midi { ref message, .. } = event {
+            update_keys(&mut*self.held.write().unwrap(), message);
+        }
+    }
+    /// Write a chunk of MIDI data from the output buffer to the output port.
+    pub fn buffer_emit (&mut self, scope: &ProcessScope) {
+        let samples = scope.n_frames() as usize;
+        let mut writer = self.port.writer(scope);
+        for (time, events) in self.output_buffer.iter().enumerate().take(samples) {
+            for bytes in events.iter() {
+                writer.write(&RawMidi { time: time as u32, bytes }).unwrap_or_else(|_|{
+                    panic!("Failed to write MIDI data: {bytes:?}");
+                });
+            }
+        }
+    }
+}
+
+impl AsRef<Port<MidiOut>> for JackMidiOut {
+    fn as_ref (&self) -> &Port<MidiOut> {
+        &self.port
+    }
+}
+
+impl JackPort for JackMidiOut {
+    type Port = MidiOut;
+    type Pair = MidiIn;
+    fn port (&self) -> &Port<MidiOut> { &self.port }
+}
+
+impl JackPortConnect<&str> for JackMidiOut {
+    fn connect_to (&self, to: &str) -> Usually<PortConnectStatus> {
+        self.with_client(|c|if let Some(ref port) = c.port_by_name(to.as_ref()) {
+            self.connect_to(port)
+        } else {
+            Ok(Missing)
+        })
+    }
+}
+
+impl JackPortConnect<&Port<Unowned>> for JackMidiOut {
+    fn connect_to (&self, port: &Port<Unowned>) -> Usually<PortConnectStatus> {
+        self.with_client(|c|Ok(if let Ok(_) = c.connect_ports(&self.port, port) {
+            Connected
+        } else if let Ok(_) = c.connect_ports(port, &self.port) {
+            Connected
+        } else {
+            Mismatch
+        }))
+    }
+}
+
+impl JackPortConnect<&Port<MidiIn>> for JackMidiOut {
+    fn connect_to (&self, port: &Port<MidiIn>) -> Usually<PortConnectStatus> {
+        self.with_client(|c|Ok(if let Ok(_) = c.connect_ports(&self.port, port) {
+            Connected
+        } else if let Ok(_) = c.connect_ports(port, &self.port) {
+            Connected
+        } else {
+            Mismatch
+        }))
+    }
+}
+
+impl JackPortAutoconnect for JackMidiOut {
+    fn conn (&self) -> &[PortConnect] {
+        &self.conn
+    }
+}
+
 #[tengri_proc::command(JackMidiOut)]
 impl MidiOutputCommand {
 }
@@ -29,6 +175,11 @@ pub trait HasMidiOuts {
             data
         })
     }
+    fn midi_outs_emit (&mut self, scope: &ProcessScope) {
+        for port in self.midi_outs_mut().iter_mut() {
+            port.buffer_emit(scope)
+        }
+    }
 }
 
 /// Trail for thing that may gain new MIDI ports.
diff --git a/deps/tengri b/deps/tengri
index bad20f50..a9619ab9 160000
--- a/deps/tengri
+++ b/deps/tengri
@@ -1 +1 @@
-Subproject commit bad20f5037dc22d572a8381840fab871ce65f565
+Subproject commit a9619ab9cea40aed3ec30483f4a7db03ca7fec9d