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Grid Anchor (Bar-1 Detection)

Flag: --choose-grid-anchor

The automatic pipeline estimates where bar 1 starts using the first strong transient. This works for most songs, but some arrangements make it ambiguous.

Tricky cases this handles

  • Sparse intros — pad or ambient texture with no clear rhythmic hit
  • Pickups / anacrusis — a melodic phrase that starts before bar 1 (e.g. "and-a one, two, three, four")
  • Weak first kick — the downbeat exists but is softer than a later hit, so beat tracking latches onto the wrong transient
  • FX-only openings — risers, sweeps, or reverse crashes before the actual music starts
  • First transient ≠ musical downbeat — a vocal ad-lib, guitar scrape, or click that happens before the arrangement begins

How it works

Analyzes beat interval regularity (sliding-window std dev), onset positions relative to the beat grid, and leading silence duration. Generates a ranked list of anchor candidates with confidence scores and a recommended pick.

When to use it

  • When the automatic alignment sounds off by a beat or half-bar
  • When the song starts with a long intro that doesn't have a clear kick
  • When you're batch-processing and want to flag songs that need manual review

Example

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# Analyze candidates
suno-to-ableton choose-grid-anchor /path/to/my-song

# Apply the recommended anchor during processing
suno-to-ableton process /path/to/my-song --choose-grid-anchor --apply

What --apply does

Without --apply, prints the candidate list with confidence scores. With --apply, adjusts the global offset to use the recommended anchor point.