diff --git a/bin/cli_arranger.rs b/bin/cli_arranger.rs
index 5cf780db..e275ff09 100644
--- a/bin/cli_arranger.rs
+++ b/bin/cli_arranger.rs
@@ -38,7 +38,7 @@ impl ArrangerCli {
         if let Some(name) = self.name.as_ref() {
             client_name = name.clone();
         }
-        Tui::run(JackClient::new(client_name.as_str())?.activate_with(|jack|{
+        Tui::run(JackConnection::new(client_name.as_str())?.activate_with(|jack|{
             let mut app = ArrangerTui::try_from(jack)?;
             let jack  = jack.read().unwrap();
             app.color = ItemPalette::random();
@@ -50,7 +50,7 @@ impl ArrangerCli {
     }
 }
 
-fn add_tracks (jack: &JackClient, app: &mut ArrangerTui, cli: &ArrangerCli) -> Usually<()> {
+fn add_tracks (jack: &JackConnection, app: &mut ArrangerTui, cli: &ArrangerCli) -> Usually<()> {
     let n = cli.tracks;
     let track_color_1 = ItemColor::random();
     let track_color_2 = ItemColor::random();
diff --git a/bin/cli_groovebox.rs b/bin/cli_groovebox.rs
index dcc85a17..59e3c663 100644
--- a/bin/cli_groovebox.rs
+++ b/bin/cli_groovebox.rs
@@ -33,7 +33,7 @@ pub struct GrooveboxCli {
 }
 impl GrooveboxCli {
     fn run (&self) -> Usually<()> {
-        Tui::run(JackClient::new("tek_groovebox")?.activate_with(|jack|{
+        Tui::run(JackConnection::new("tek_groovebox")?.activate_with(|jack|{
             let app = tek::GrooveboxTui::try_from(jack)?;
             jack.read().unwrap().client().connect_ports(&app.player.midi_outs[0], &app.sampler.midi_in)?;
             jack.connect_midi_from(&app.player.midi_ins[0],    &self.midi_from)?;
@@ -44,11 +44,10 @@ impl GrooveboxCli {
             jack.connect_audio_to(&app.sampler.audio_outs[0],  &self.l_to)?;
             jack.connect_audio_to(&app.sampler.audio_outs[1],  &self.r_to)?;
             if self.sync {
-                jack.read().unwrap().client().register_timebase_callback(false, |state|{
-                    let ::jack::contrib::TimebaseInfo { state, new_pos, nframes, mut position } = state;
-                    app.clock().playhead.update_from_sample(position.frame() as f64);
-                    position.bbt = Some(app.clock().bbt());
-                    position
+                jack.read().unwrap().client().register_timebase_callback(false, |mut state|{
+                    app.clock().playhead.update_from_sample(state.position.frame() as f64);
+                    state.position.bbt = Some(app.clock().bbt());
+                    state.position
                 })?
             }
             Ok(app)
diff --git a/bin/cli_sampler.rs b/bin/cli_sampler.rs
index ae7f7bd1..b2305de6 100644
--- a/bin/cli_sampler.rs
+++ b/bin/cli_sampler.rs
@@ -8,7 +8,7 @@ pub fn main () -> Usually<()> { SamplerCli::parse().run() }
 }
 impl SamplerCli {
     fn run (&self) -> Usually<()> {
-        Tui::run(JackClient::new("tek_sampler")?.activate_with(|x|{
+        Tui::run(JackConnection::new("tek_sampler")?.activate_with(|x|{
             let sampler = tek::SamplerTui::try_from(x)?;
             Ok(sampler)
         })?)?;
diff --git a/bin/cli_sequencer.rs b/bin/cli_sequencer.rs
index e8474507..a5ef676b 100644
--- a/bin/cli_sequencer.rs
+++ b/bin/cli_sequencer.rs
@@ -25,7 +25,7 @@ pub struct SequencerCli {
 impl SequencerCli {
     fn run (&self) -> Usually<()> {
         let name = self.name.as_deref().unwrap_or("tek_sequencer");
-        Tui::run(JackClient::new(name)?.activate_with(|jack|{
+        Tui::run(JackConnection::new(name)?.activate_with(|jack|{
             let mut app  = SequencerTui::try_from(jack)?;
             let jack     = jack.read().unwrap();
             let midi_in  = jack.register_port("i", MidiIn::default())?;
diff --git a/bin/cli_transport.rs b/bin/cli_transport.rs
index 942978fe..bb2e56b6 100644
--- a/bin/cli_transport.rs
+++ b/bin/cli_transport.rs
@@ -2,7 +2,7 @@ include!("./lib.rs");
 
 /// Application entrypoint.
 pub fn main () -> Usually<()> {
-    Tui::run(JackClient::new("tek_transport")?.activate_with(|jack|{
+    Tui::run(JackConnection::new("tek_transport")?.activate_with(|jack|{
         TransportTui::try_from(jack)
     })?)?;
     Ok(())
diff --git a/bin/lib.rs b/bin/lib.rs
index 538ecfe7..87eec13e 100644
--- a/bin/lib.rs
+++ b/bin/lib.rs
@@ -3,7 +3,7 @@
 #[allow(unused_imports)] use tek::{*, jack::*};
 
 #[allow(unused)]
-fn connect_from (jack: &JackClient, input: &Port<MidiIn>, ports: &[String]) -> Usually<()> {
+fn connect_from (jack: &JackConnection, input: &Port<MidiIn>, ports: &[String]) -> Usually<()> {
     for port in ports.iter() {
         if let Some(port) = jack.port_by_name(port).as_ref() {
             jack.client().connect_ports(port, input)?;
@@ -15,7 +15,7 @@ fn connect_from (jack: &JackClient, input: &Port<MidiIn>, ports: &[String]) -> U
 }
 
 #[allow(unused)]
-fn connect_to (jack: &JackClient, output: &Port<MidiOut>, ports: &[String]) -> Usually<()> {
+fn connect_to (jack: &JackConnection, output: &Port<MidiOut>, ports: &[String]) -> Usually<()> {
     for port in ports.iter() {
         if let Some(port) = jack.port_by_name(port).as_ref() {
             jack.client().connect_ports(output, port)?;
@@ -27,7 +27,7 @@ fn connect_to (jack: &JackClient, output: &Port<MidiOut>, ports: &[String]) -> U
 }
 
 #[allow(unused)]
-fn connect_audio_from (jack: &JackClient, input: &Port<AudioIn>, ports: &[String]) -> Usually<()> {
+fn connect_audio_from (jack: &JackConnection, input: &Port<AudioIn>, ports: &[String]) -> Usually<()> {
     for port in ports.iter() {
         if let Some(port) = jack.port_by_name(port).as_ref() {
             jack.client().connect_ports(port, input)?;
@@ -39,7 +39,7 @@ fn connect_audio_from (jack: &JackClient, input: &Port<AudioIn>, ports: &[String
 }
 
 #[allow(unused)]
-fn connect_audio_to (jack: &JackClient, output: &Port<AudioOut>, ports: &[String]) -> Usually<()> {
+fn connect_audio_to (jack: &JackConnection, output: &Port<AudioOut>, ports: &[String]) -> Usually<()> {
     for port in ports.iter() {
         if let Some(port) = jack.port_by_name(port).as_ref() {
             jack.client().connect_ports(output, port)?;
diff --git a/bin/todo_cli_mixer.rs b/bin/todo_cli_mixer.rs
index 4130dde9..e419ffed 100644
--- a/bin/todo_cli_mixer.rs
+++ b/bin/todo_cli_mixer.rs
@@ -13,7 +13,7 @@ pub fn main () -> Usually<()> {
 
 impl MixerCli {
     fn run (&self) -> Usually<()> {
-        Tui::run(JackClient::new("tek_mixer")?.activate_with(|jack|{
+        Tui::run(JackConnection::new("tek_mixer")?.activate_with(|jack|{
             let mut mixer = Mixer::new(jack, self.name.as_ref().map(|x|x.as_str()).unwrap_or("mixer"))?;
             for channel in 0..self.channels.unwrap_or(8) {
                 mixer.track_add(&format!("Track {}", channel + 1), 1)?;
diff --git a/bin/todo_cli_plugin.rs b/bin/todo_cli_plugin.rs
index 1b5a1ce5..cfb81fe2 100644
--- a/bin/todo_cli_plugin.rs
+++ b/bin/todo_cli_plugin.rs
@@ -13,7 +13,7 @@ pub fn main () -> Usually<()> {
 
 impl PluginCli {
     fn run (&self) -> Usually<()> {
-        Tui::run(JackClient::new("tek_plugin")?.activate_with(|jack|{
+        Tui::run(JackConnection::new("tek_plugin")?.activate_with(|jack|{
             let mut plugin = Plugin::new_lv2(
                 jack,
                 self.name.as_ref().map(|x|x.as_str()).unwrap_or("mixer"),
diff --git a/bin/todo_cli_sampler.rs b/bin/todo_cli_sampler.rs
index bb72ec71..75e4c62a 100644
--- a/bin/todo_cli_sampler.rs
+++ b/bin/todo_cli_sampler.rs
@@ -13,7 +13,7 @@ pub fn main () -> Usually<()> {
 
 impl SamplerCli {
     fn run (&self) -> Usually<()> {
-        Tui::run(JackClient::new("tek_sampler")?.activate_with(|jack|{
+        Tui::run(JackConnection::new("tek_sampler")?.activate_with(|jack|{
             let mut plugin = Sampler::new(
                 jack,
                 self.name.as_ref().map(|x|x.as_str()).unwrap_or("mixer"),
diff --git a/src/arranger.rs b/src/arranger.rs
index 9aea0de3..6b4ab255 100644
--- a/src/arranger.rs
+++ b/src/arranger.rs
@@ -10,7 +10,7 @@ mod arranger_h;
 
 /// Root view for standalone `tek_arranger`
 pub struct ArrangerTui {
-    jack:         Arc<RwLock<JackClient>>,
+    jack:         Arc<RwLock<JackConnection>>,
     pub clock:    ClockModel,
     pub phrases:  PoolModel,
     pub tracks:   Vec<ArrangerTrack>,
diff --git a/src/edn.rs b/src/edn.rs
index 8067b562..289d3e81 100644
--- a/src/edn.rs
+++ b/src/edn.rs
@@ -33,7 +33,7 @@ pub trait FromEdn<C>: Sized {
     }
 }
 
-from_edn!("sampler" => |jack: &Arc<RwLock<JackClient>>, args| -> crate::Sampler {
+from_edn!("sampler" => |jack: &Arc<RwLock<JackConnection>>, args| -> crate::Sampler {
     let mut name = String::new();
     let mut dir  = String::new();
     let mut samples = BTreeMap::new();
@@ -64,7 +64,7 @@ from_edn!("sampler" => |jack: &Arc<RwLock<JackClient>>, args| -> crate::Sampler
 
 type MidiSample = (Option<u7>, Arc<RwLock<crate::Sample>>);
 
-from_edn!("sample" => |(_jack, dir): (&Arc<RwLock<JackClient>>, &str), args| -> MidiSample {
+from_edn!("sample" => |(_jack, dir): (&Arc<RwLock<JackConnection>>, &str), args| -> MidiSample {
     let mut name = String::new();
     let mut file = String::new();
     let mut midi = None;
@@ -97,7 +97,7 @@ from_edn!("sample" => |(_jack, dir): (&Arc<RwLock<JackClient>>, &str), args| ->
     }))))
 });
 
-from_edn!("plugin/lv2" => |jack: &Arc<RwLock<JackClient>>, args| -> Plugin {
+from_edn!("plugin/lv2" => |jack: &Arc<RwLock<JackConnection>>, args| -> Plugin {
     let mut name = String::new();
     let mut path = String::new();
     edn!(edn in args {
@@ -119,7 +119,7 @@ const SYM_GAIN:    &str = ":gain";
 const SYM_SAMPLER: &str = "sampler";
 const SYM_LV2:     &str = "lv2";
 
-from_edn!("mixer/track" => |jack: &Arc<RwLock<JackClient>>, args| -> MixerTrack {
+from_edn!("mixer/track" => |jack: &Arc<RwLock<JackConnection>>, args| -> MixerTrack {
     let mut _gain = 0.0f64;
     let mut track = MixerTrack {
         name:       String::new(),
diff --git a/src/groovebox.rs b/src/groovebox.rs
index 932fcd5a..d3659008 100644
--- a/src/groovebox.rs
+++ b/src/groovebox.rs
@@ -7,7 +7,7 @@ use PhraseCommand::*;
 use PhrasePoolCommand::*;
 
 pub struct GrooveboxTui {
-    _jack: Arc<RwLock<JackClient>>,
+    _jack: Arc<RwLock<JackConnection>>,
 
     pub player:    MidiPlayer,
     pub pool:      PoolModel,
diff --git a/src/jack.rs b/src/jack.rs
index fae62340..bf729a57 100644
--- a/src/jack.rs
+++ b/src/jack.rs
@@ -15,7 +15,7 @@ pub use self::activate::JackActivate;
 
 pub mod client;
 pub(crate) use self::client::*;
-pub use self::client::JackClient;
+pub use self::client::JackConnection;
 
 pub mod jack_event;
 pub(crate) use self::jack_event::*;
@@ -24,12 +24,12 @@ pub mod ports;
 pub(crate) use self::ports::*;
 pub use self::ports::RegisterPort;
 
-/// Implement [TryFrom<&Arc<RwLock<JackClient>>>]: create app state from wrapped JACK handle.
+/// Implement [TryFrom<&Arc<RwLock<JackConnection>>>]: create app state from wrapped JACK handle.
 #[macro_export] macro_rules! from_jack {
     (|$jack:ident|$Struct:ident$(<$($L:lifetime),*$($T:ident$(:$U:path)?),*>)? $cb:expr) => {
-        impl $(<$($L),*$($T $(: $U)?),*>)? TryFrom<&Arc<RwLock<JackClient>>> for $Struct $(<$($L),*$($T),*>)? {
+        impl $(<$($L),*$($T $(: $U)?),*>)? TryFrom<&Arc<RwLock<JackConnection>>> for $Struct $(<$($L),*$($T),*>)? {
             type Error = Box<dyn std::error::Error>;
-            fn try_from ($jack: &Arc<RwLock<JackClient>>) -> Usually<Self> {
+            fn try_from ($jack: &Arc<RwLock<JackConnection>>) -> Usually<Self> {
                 Ok($cb)
             }
         }
diff --git a/src/jack/activate.rs b/src/jack/activate.rs
index 37829f3c..5b7e4923 100644
--- a/src/jack/activate.rs
+++ b/src/jack/activate.rs
@@ -3,15 +3,15 @@ use crate::*;
 pub trait JackActivate: Sized {
     fn activate_with <T: Audio + 'static> (
         self,
-        init: impl FnOnce(&Arc<RwLock<JackClient>>)->Usually<T>
+        init: impl FnOnce(&Arc<RwLock<JackConnection>>)->Usually<T>
     )
         -> Usually<Arc<RwLock<T>>>;
 }
 
-impl JackActivate for JackClient {
+impl JackActivate for JackConnection {
     fn activate_with <T: Audio + 'static> (
         self,
-        init: impl FnOnce(&Arc<RwLock<JackClient>>)->Usually<T>
+        init: impl FnOnce(&Arc<RwLock<JackConnection>>)->Usually<T>
     )
         -> Usually<Arc<RwLock<T>>>
     {
diff --git a/src/jack/client.rs b/src/jack/client.rs
index be18cb0f..674737fd 100644
--- a/src/jack/client.rs
+++ b/src/jack/client.rs
@@ -4,7 +4,7 @@ pub type DynamicAudioHandler = ClosureProcessHandler<(), BoxedAudioHandler>;
 pub type BoxedAudioHandler = Box<dyn FnMut(&Client, &ProcessScope) -> Control + Send>;
 /// Wraps [Client] or [DynamicAsyncClient] in place.
 #[derive(Debug)]
-pub enum JackClient {
+pub enum JackConnection {
     /// Before activation.
     Inactive(Client),
     /// During activation.
@@ -12,18 +12,19 @@ pub enum JackClient {
     /// After activation. Must not be dropped for JACK thread to persist.
     Active(DynamicAsyncClient),
 }
-from!(|jack: JackClient|Client = match jack {
-    JackClient::Inactive(client) => client,
-    JackClient::Activating       => panic!("jack client still activating"),
-    JackClient::Active(_)        => panic!("jack client already activated"),
+from!(|jack: JackConnection|Client = match jack {
+    JackConnection::Inactive(client) => client,
+    JackConnection::Activating       => panic!("jack client still activating"),
+    JackConnection::Active(_)        => panic!("jack client already activated"),
 });
-impl JackClient {
+impl JackConnection {
     pub fn new (name: &str) -> Usually<Self> {
         let (client, _) = Client::new(name, ClientOptions::NO_START_SERVER)?;
         Ok(Self::Inactive(client))
     }
 }
-impl AudioEngine for JackClient {
+impl AudioEngine for JackConnection {
+    /// Return the internal [Client] handle that lets you call the JACK API.
     fn client(&self) -> &Client {
         match self {
             Self::Inactive(ref client) => client,
@@ -31,6 +32,10 @@ impl AudioEngine for JackClient {
             Self::Active(ref client)   => client.as_client(),
         }
     }
+    /// Bind a process callback to a `JackConnection::Inactive`,
+    /// turning it into a `JackConnection::Active`. Needs work.
+    /// Strange ownership situation between the callback and
+    /// the host object.
     fn activate(
         self,
         mut cb: impl FnMut(&Arc<RwLock<Self>>, &Client, &ProcessScope) -> Control + Send + 'static,
diff --git a/src/jack/ports.rs b/src/jack/ports.rs
index d65ac790..584207cf 100644
--- a/src/jack/ports.rs
+++ b/src/jack/ports.rs
@@ -11,7 +11,7 @@ pub trait RegisterPort {
     fn connect_audio_to   (&self, my_output: &Port<AudioOut>, ports: &[String]) -> Usually<()>;
 }
 
-impl RegisterPort for Arc<RwLock<JackClient>> {
+impl RegisterPort for Arc<RwLock<JackConnection>> {
     fn midi_in (&self, name: &str) -> Usually<Port<MidiIn>> {
         Ok(self.read().unwrap().client().register_port(name, MidiIn::default())?)
     }
diff --git a/src/midi.rs b/src/midi.rs
index da2f3018..f9c483aa 100644
--- a/src/midi.rs
+++ b/src/midi.rs
@@ -127,7 +127,7 @@ pub struct MidiPlayer {
     pub note_buf:           Vec<u8>,
 }
 impl MidiPlayer {
-    pub fn new (jack: &Arc<RwLock<JackClient>>, name: &str) -> Usually<Self> {
+    pub fn new (jack: &Arc<RwLock<JackConnection>>, name: &str) -> Usually<Self> {
         Ok(Self {
             clock:       ClockModel::from(jack),
             play_phrase: None,
@@ -324,7 +324,7 @@ impl HasPlayPhrase for MidiPlayer {
 ///// Methods used primarily by the process callback
 //impl MIDIPlayer {
     //pub fn new (
-        //jack:  &Arc<RwLock<JackClient>>,
+        //jack:  &Arc<RwLock<JackConnection>>,
         //clock: &Arc<Clock>,
         //name:  &str
     //) -> Usually<Self> {
diff --git a/src/mixer.rs b/src/mixer.rs
index 71aba47f..54c28716 100644
--- a/src/mixer.rs
+++ b/src/mixer.rs
@@ -3,7 +3,7 @@ use crate::*;
 #[derive(Debug)]
 pub struct Mixer {
     /// JACK client handle (needs to not be dropped for standalone mode to work).
-    pub jack:            Arc<RwLock<JackClient>>,
+    pub jack:            Arc<RwLock<JackConnection>>,
     pub name:            String,
     pub tracks:          Vec<MixerTrack>,
     pub selected_track:  usize,
@@ -25,7 +25,7 @@ pub struct MixerTrack {
 audio!(|self: Mixer, _client, _scope|Control::Continue);
 
 impl Mixer {
-    pub fn new (jack: &Arc<RwLock<JackClient>>, name: &str) -> Usually<Self> {
+    pub fn new (jack: &Arc<RwLock<JackConnection>>, name: &str) -> Usually<Self> {
         Ok(Self {
             jack: jack.clone(),
             name: name.into(),
diff --git a/src/plugin.rs b/src/plugin.rs
index 63595c17..c6f8e493 100644
--- a/src/plugin.rs
+++ b/src/plugin.rs
@@ -7,7 +7,7 @@ pub use self::lv2::LV2Plugin;
 #[derive(Debug)]
 pub struct Plugin {
     /// JACK client handle (needs to not be dropped for standalone mode to work).
-    pub jack:       Arc<RwLock<JackClient>>,
+    pub jack:       Arc<RwLock<JackConnection>>,
     pub name:       String,
     pub path:       Option<String>,
     pub plugin:     Option<PluginKind>,
@@ -40,7 +40,7 @@ impl Debug for PluginKind {
 }
 impl Plugin {
     pub fn new_lv2 (
-        jack: &Arc<RwLock<JackClient>>,
+        jack: &Arc<RwLock<JackConnection>>,
         name: &str,
         path: &str,
     ) -> Usually<Self> {
@@ -131,7 +131,7 @@ audio!(|self: PluginAudio, client, scope|{
 impl Plugin {
     /// Create a plugin host device.
     pub fn new (
-        jack: &Arc<RwLock<JackClient>>,
+        jack: &Arc<RwLock<JackConnection>>,
         name: &str,
     ) -> Usually<Self> {
         Ok(Self {
diff --git a/src/sampler.rs b/src/sampler.rs
index 54926e09..363bba41 100644
--- a/src/sampler.rs
+++ b/src/sampler.rs
@@ -35,7 +35,7 @@ pub use self::sample_viewer::SampleViewer;
 /// The sampler plugin plays sounds.
 #[derive(Debug)]
 pub struct Sampler {
-    pub jack:        Arc<RwLock<JackClient>>,
+    pub jack:        Arc<RwLock<JackConnection>>,
     pub name:        String,
     pub mapped:      [Option<Arc<RwLock<Sample>>>;128],
     pub recording:   Option<(usize, Arc<RwLock<Sample>>)>,
@@ -49,7 +49,7 @@ pub struct Sampler {
     pub output_gain: f32
 }
 impl Sampler {
-    pub fn new (jack: &Arc<RwLock<JackClient>>, name: &str) -> Usually<Self> {
+    pub fn new (jack: &Arc<RwLock<JackConnection>>, name: &str) -> Usually<Self> {
         Ok(Self {
             midi_in: jack.midi_in(&format!("M/{name}"))?,
             audio_ins:   vec![
diff --git a/src/sequencer.rs b/src/sequencer.rs
index 791279c9..d24f5511 100644
--- a/src/sequencer.rs
+++ b/src/sequencer.rs
@@ -6,7 +6,7 @@ use PhraseCommand::*;
 use PhrasePoolCommand::*;
 /// Root view for standalone `tek_sequencer`.
 pub struct SequencerTui {
-    _jack: Arc<RwLock<JackClient>>,
+    _jack: Arc<RwLock<JackConnection>>,
     pub transport: bool, 
     pub selectors: bool, 
     pub clock:     ClockModel,
diff --git a/src/time.rs b/src/time.rs
index 0f1241c8..a8fd4112 100644
--- a/src/time.rs
+++ b/src/time.rs
@@ -82,7 +82,7 @@ pub struct ClockModel {
     pub chunk:     Arc<AtomicUsize>,
 }
 
-from!(|jack: &Arc<RwLock<JackClient>>| ClockModel = {
+from!(|jack: &Arc<RwLock<JackConnection>>| ClockModel = {
     let jack      = jack.read().unwrap();
     let chunk     = jack.client().buffer_size();
     let transport = jack.client().transport();
diff --git a/src/transport.rs b/src/transport.rs
index 629217d1..5a1cb9e2 100644
--- a/src/transport.rs
+++ b/src/transport.rs
@@ -5,7 +5,7 @@ use FocusCommand::{Next, Prev};
 use KeyCode::{Enter, Left, Right, Char};
 /// Transport clock app.
 pub struct TransportTui {
-    pub jack:   Arc<RwLock<JackClient>>,
+    pub jack:   Arc<RwLock<JackConnection>>,
     pub clock:  ClockModel,
     pub size:   Measure<Tui>,
     pub cursor: (usize, usize),