feat(anvil): add Kick lock with offset audition

Anvil gets a sidechain input named Kick. With Kick lock on, kicks are
found on the undelayed sidechain, so with the lookahead each hit ducks
the sub (Duck, Release) when the delayed kick plays and restarts the sub
at Phase, shifted by Offset (-30 to +30 ms, also before the kick).

The Audition steps the offset from -30 to +30 ms, 4 kicks each, and
measures how kick and sub sum below 150 Hz after each hit; Keep takes the
offset heard. On a 55 Hz kick burst against a 55 Hz sub the sum peaks at
0 ms (+2.4 dB) and nearly again one period away (+/-20 ms), so the bars
check the choice by ear rather than make it.

tools/editor-check/src/main.rs

@@ -99,13 +99,26 @@ fn main() {
     let mut anvil_state = anvil_ui::State::default();
     if anvil {
         anvil_settings.ghost = 60.;
+        anvil_settings.kick_lock = true;
+        anvil_state.audition = true;
+        let monitor = anvil_core::Monitor {
+            audition: true,
+            ..Default::default()
+        };
         let mut engine = anvil_core::Engine::new(48000., 2).unwrap();
         engine.set_settings(anvil_settings).unwrap();
         let mut saw = common_dsp::Saw::new(48000., 43.65);
-        for i in 0..36000 {
-            // A distorted F1 bass whose own sub drifts in phase and level.
+        let total = 300000;
+        for i in 0..total {
+            // A distorted F1 bass whose own sub drifts in phase and level, and a kick every
+            // 0.2 s in the sidechain while the audition runs.
             let x = (saw.sample() * 1.6 + 0.3 * (i as f32 * 0.0009).sin()).tanh() * 0.4;
-            engine.process_sample([x, x], anvil_core::Monitor::default());
+            let t = (i % 9600) as f32 / 48000.;
+            let kick = 0.8 * (std::f32::consts::TAU * 50. * t).sin() * (-t / 0.06).exp();
+            engine.process_with_kick([x, x], kick, monitor);
+            if i < total - 36000 {
+                continue;
+            }
             if i % 1600 == 0 {
                 anvil_state.accept_frame(engine.take_analyzer());
             }