diff --git a/src/engine/dispatcher.rs b/src/engine/dispatcher.rs
index 8ad28ae..4c3833f 100644
--- a/src/engine/dispatcher.rs
+++ b/src/engine/dispatcher.rs
@@ -23,8 +23,6 @@ pub enum DispatchCommand {
     Audio { cmd: String, time: Option<f64> },
     Midi(MidiCommand),
     FlushMidi,
-    Hush,
-    Panic,
 }
 
 impl Ord for TimedCommand {
@@ -152,12 +150,6 @@ fn dispatch_command(
                 }
             }
         }
-        DispatchCommand::Hush => {
-            let _ = audio_tx.load().try_send(AudioCommand::Hush);
-        }
-        DispatchCommand::Panic => {
-            let _ = audio_tx.load().try_send(AudioCommand::Panic);
-        }
     }
 }
 
@@ -170,15 +162,15 @@ mod tests {
         let mut heap: BinaryHeap<TimedCommand> = BinaryHeap::new();
 
         heap.push(TimedCommand {
-            command: DispatchCommand::Hush,
+            command: DispatchCommand::FlushMidi,
             target_time_us: 300,
         });
         heap.push(TimedCommand {
-            command: DispatchCommand::Hush,
+            command: DispatchCommand::FlushMidi,
             target_time_us: 100,
         });
         heap.push(TimedCommand {
-            command: DispatchCommand::Hush,
+            command: DispatchCommand::FlushMidi,
             target_time_us: 200,
         });
 
diff --git a/src/engine/link.rs b/src/engine/link.rs
index 398b66d..1ef04f8 100644
--- a/src/engine/link.rs
+++ b/src/engine/link.rs
@@ -86,10 +86,4 @@ impl LinkState {
         self.link.capture_app_session_state(&mut state);
         state
     }
-
-    pub fn beat_at_time(&self, time_us: i64, quantum: f64) -> f64 {
-        let mut state = SessionState::new();
-        self.link.capture_app_session_state(&mut state);
-        state.beat_at_time(time_us, quantum)
-    }
 }
diff --git a/src/engine/timing.rs b/src/engine/timing.rs
index 3930d95..ea7370b 100644
--- a/src/engine/timing.rs
+++ b/src/engine/timing.rs
@@ -12,10 +12,6 @@ fn beats_to_micros(beats: f64, tempo: f64) -> SyncTime {
 /// Timing boundary types for step and pattern scheduling.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum StepTiming {
-    /// Fire at a specific absolute substep number.
-    Substep(u64),
-    /// Fire when any substep boundary is crossed (4 substeps per beat).
-    NextSubstep,
     /// Fire when a beat boundary is crossed.
     NextBeat,
     /// Fire when a bar/quantum boundary is crossed.
@@ -29,18 +25,10 @@ impl StepTiming {
             return false;
         }
         match self {
-            Self::NextSubstep => {
-                (prev_beat * 4.0).floor() as i64 != (curr_beat * 4.0).floor() as i64
-            }
             Self::NextBeat => prev_beat.floor() as i64 != curr_beat.floor() as i64,
             Self::NextBar => {
                 (prev_beat / quantum).floor() as i64 != (curr_beat / quantum).floor() as i64
             }
-            Self::Substep(target) => {
-                let prev_substep = (prev_beat * 4.0).floor() as i64;
-                let curr_substep = (curr_beat * 4.0).floor() as i64;
-                prev_substep < *target as i64 && curr_substep >= *target as i64
-            }
         }
     }
 }
@@ -85,16 +73,6 @@ mod tests {
         assert_eq!(beats_to_micros(1.0, 0.0), 0);
     }
 
-    #[test]
-    fn test_step_timing_substep_crossed() {
-        // Crossing from substep 0 to substep 1 (beat 0.0 to 0.26)
-        assert!(StepTiming::NextSubstep.crossed(0.0, 0.26, 4.0));
-        // Not crossing (both in same substep)
-        assert!(!StepTiming::NextSubstep.crossed(0.26, 0.27, 4.0));
-        // Negative prev_beat returns false
-        assert!(!StepTiming::NextSubstep.crossed(-1.0, 0.5, 4.0));
-    }
-
     #[test]
     fn test_step_timing_beat_crossed() {
         // Crossing from beat 0 to beat 1
@@ -115,16 +93,6 @@ mod tests {
         assert!(StepTiming::NextBar.crossed(7.9, 8.1, 8.0));
     }
 
-    #[test]
-    fn test_step_timing_at_substep() {
-        // Crossing to substep 4 (beat 1.0)
-        assert!(StepTiming::Substep(4).crossed(0.9, 1.1, 4.0));
-        // Not yet at substep 4
-        assert!(!StepTiming::Substep(4).crossed(0.5, 0.9, 4.0));
-        // Already past substep 4
-        assert!(!StepTiming::Substep(4).crossed(1.5, 2.0, 4.0));
-    }
-
     #[test]
     fn test_substeps_crossed_normal() {
         // One substep crossed at 1x speed