1 files changed, 8 insertions, 0 deletions
diff --git a/TODO.md b/TODO.md
index c5b71e9..eb530ec 100644
--- a/TODO.md
+++ b/TODO.md
@@ -21,6 +21,14 @@ Procedural spectrogram tool: 50-100× compression (5 KB .spec → ~100 bytes C++
 `fft_radix2` now computes `wr = cosf(angle*k); wi = sinf(angle*k);` directly per k.
 Tests A–E added to `test_fft.cc`. `arrays_match` default tolerance reverted to 5e-3.
 
+## Priority 4: Audio Timing Drift [LOW PRIORITY]
+
+Events trigger ~180ms early over 63 beats @ BPM=90. Observed: beat 63 snare at
+41.82s in WAV, should be 42.00s. Root cause unknown — suspects:
+1. `chunk_frames = (int)(dt * sample_rate)` truncation (~27ms cumulative, not 180ms)
+2. Systematic bias in `unit_duration_sec` BPM calculation
+3. Mismatch between tracker time and actual sample rendering
+
 ## Priority 4: Audio System Enhancements [LOW PRIORITY]
 
 1. **`synth.cc`: use `ola_decode()` from `src/audio/ola.h`** — the OLA decode logic in