diff --git a/crates/tek_core/src/time.rs b/crates/tek_core/src/time.rs
index 35a63ace..7f14578b 100644
--- a/crates/tek_core/src/time.rs
+++ b/crates/tek_core/src/time.rs
@@ -34,9 +34,8 @@ macro_rules! impl_op {
     }
 }
 /// Define and implement a unit of time
-macro_rules! time_unit {
+macro_rules! impl_time_unit {
     ($T:ident) => {
-        #[derive(Debug, Default)] pub struct $T(AtomicF64);
         impl TimeUnit for $T {
             fn get (&self) -> f64 { self.0.load(Ordering::Relaxed) }
             fn set (&self, value: f64) { self.0.store(value, Ordering::Relaxed) }
@@ -56,7 +55,9 @@ macro_rules! time_unit {
     }
 }
 
-time_unit!(SampleRate);
+/// Audio sample rate in Hz (samples per second)
+#[derive(Debug, Default)] pub struct SampleRate(AtomicF64);
+impl_time_unit!(SampleRate);
 impl SampleRate {
     /// Return the duration of a sample in microseconds (floating)
     #[inline] pub fn usec_per_sample (&self) -> f64 {
@@ -76,11 +77,17 @@ impl SampleRate {
     }
 }
 
-time_unit!(BeatsPerMinute);
+/// Tempo in beats per minute
+#[derive(Debug, Default)] pub struct BeatsPerMinute(AtomicF64);
+impl_time_unit!(BeatsPerMinute);
 
-time_unit!(PulsesPerQuaver);
+/// MIDI resolution in PPQ (pulses per quarter note)
+#[derive(Debug, Default)] pub struct PulsesPerQuaver(AtomicF64);
+impl_time_unit!(PulsesPerQuaver);
 
-time_unit!(Microsecond);
+/// Timestamp in microseconds
+#[derive(Debug, Default)] pub struct Microsecond(AtomicF64);
+impl_time_unit!(Microsecond);
 impl Microsecond {
     #[inline] pub fn format_msu (&self) -> String {
         let usecs              = self.get() as usize;
@@ -90,13 +97,21 @@ impl Microsecond {
     }
 }
 
-time_unit!(SampleCount);
+/// Timestamp in audio samples
+#[derive(Debug, Default)] pub struct SampleCount(AtomicF64);
+impl_time_unit!(SampleCount);
 
-time_unit!(Pulse);
+/// Timestamp in MIDI pulses
+#[derive(Debug, Default)] pub struct Pulse(AtomicF64);
+impl_time_unit!(Pulse);
 
-time_unit!(LaunchSync);
+/// Quantization setting for launching clips
+#[derive(Debug, Default)] pub struct LaunchSync(AtomicF64);
+impl_time_unit!(LaunchSync);
 
-time_unit!(Quantize);
+/// Quantization setting for notes
+#[derive(Debug, Default)] pub struct Quantize(AtomicF64);
+impl_time_unit!(Quantize);
 
 /// Temporal resolutions: sample rate, tempo, MIDI pulses per quaver (beat)
 #[derive(Debug, Clone)]
diff --git a/crates/tek_sequencer/src/sequencer.rs b/crates/tek_sequencer/src/sequencer.rs
index 614f7d91..37972f92 100644
--- a/crates/tek_sequencer/src/sequencer.rs
+++ b/crates/tek_sequencer/src/sequencer.rs
@@ -367,7 +367,7 @@ impl Phrase {
         clone.uuid = uuid::Uuid::new_v4();
         clone
     }
-    pub fn toggle_loop  (&mut self) { self.loop_on = !self.loop_on; }
+    pub fn toggle_loop (&mut self) { self.loop_on = !self.loop_on; }
     pub fn record_event (&mut self, pulse: usize, message: MidiMessage) {
         if pulse >= self.length { panic!("extend phrase first") }
         self.notes[pulse].push(message);