diff --git a/desktop/src-tauri/examples/tts_speed_probe.rs b/desktop/src-tauri/examples/tts_speed_probe.rs
index 0eff81412..b573c1d04 100644
--- a/desktop/src-tauri/examples/tts_speed_probe.rs
+++ b/desktop/src-tauri/examples/tts_speed_probe.rs
@@ -4,7 +4,6 @@ use std::time::Instant;
 mod playback_speed_dsp;
 
 const SAMPLE_RATE: u32 = 24_000;
-const SENTENCE_LEAD_IN_SAMPLES: usize = 480;
 const TONE_SECONDS: f64 = 10.0;
 
 fn main() {
@@ -16,7 +15,6 @@ fn main() {
 
     let compensated_lookahead = playback_speed_dsp::compensated_output_latency_samples(SAMPLE_RATE);
     let compensated_lookahead_ms = compensated_lookahead as f64 * 1_000.0 / SAMPLE_RATE as f64;
-    let fixed_lead_in_ms = SENTENCE_LEAD_IN_SAMPLES as f64 * 1_000.0 / SAMPLE_RATE as f64;
 
     for speed in [0.75_f32, 1.25, 1.5] {
         let started = Instant::now();
@@ -25,7 +23,7 @@ fn main() {
         let elapsed = started.elapsed();
         println!(
             "{speed:.2}x: processing={:.2}ms, {:.3}% realtime, output={} samples, compensated \
-             lookahead={compensated_lookahead_ms:.1}ms, fixed playback lead-in={fixed_lead_in_ms:.1}ms",
+             DSP lookahead={compensated_lookahead_ms:.1}ms",
             elapsed.as_secs_f64() * 1_000.0,
             elapsed.as_secs_f64() / TONE_SECONDS * 100.0,
             output.len(),
diff --git a/desktop/src-tauri/src/huddle/playback_speed.rs b/desktop/src-tauri/src/huddle/playback_speed.rs
index 036cdc27b..07a343327 100644
--- a/desktop/src-tauri/src/huddle/playback_speed.rs
+++ b/desktop/src-tauri/src/huddle/playback_speed.rs
@@ -25,8 +25,6 @@ pub(crate) use playback_speed_dsp::process_complete_chunk;
 use playback_speed_dsp::{validate_speed, DEFAULT_PLAYBACK_SPEED};
 
 const SETTINGS_FILE: &str = "tts-playback-settings.json";
-#[cfg(test)]
-use playback_speed_dsp::UNITY_EPSILON;
 
 /// Lock-free shared control read by the TTS worker before each synthesis chunk.
 #[derive(Clone, Debug)]
@@ -135,22 +133,6 @@ fn save_to_path(path: &Path, speed: f32) -> Result<(), String> {
         .map_err(|error| format!("commit {}: {error}", resolved.display()))
 }
 
-#[cfg(test)]
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
-enum ProcessorKind {
-    Bypass,
-    Signalsmith,
-}
-
-#[cfg(test)]
-fn processor_kind(speed: f32) -> ProcessorKind {
-    if (speed - DEFAULT_PLAYBACK_SPEED).abs() <= UNITY_EPSILON {
-        ProcessorKind::Bypass
-    } else {
-        ProcessorKind::Signalsmith
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -158,9 +140,10 @@ mod tests {
     const SAMPLE_RATE: u32 = 24_000;
 
     #[test]
-    fn selects_bypass_only_at_unity() {
-        assert_eq!(processor_kind(1.0), ProcessorKind::Bypass);
-        assert_eq!(processor_kind(1.25), ProcessorKind::Signalsmith);
+    fn unity_processing_is_a_bit_exact_bypass() {
+        let input = vec![0.0, 0.125, -0.5, 1.0];
+        let output = process_complete_chunk(&input, 1.0, SAMPLE_RATE).expect("unity output");
+        assert_eq!(output, input);
     }
 
     #[test]