Seamless Audio Joins: How to Crossfade
Butt-joining two tracks makes the seam audible: a bump or a hole. A crossfade overlaps the end of A with the start of B, one fading down while the other rises, so the ear hears a blend instead of a cut. Here is how to pick the overlap and the curve.
Crossfade vs hard join
A hard join plays A fully, then B — the two never overlap; right for content-lead splices like interview segments. A crossfade overlaps A's tail with B's head, loudness trading off smoothly; right for music and atmosphere transitions.
Overlap length follows content pace
The tool spans 1-10 seconds, defaulting to 3. Speech uses 1-2 seconds so sentences do not pile up; music joins sit at 3-5 seconds for a relaxed handoff; ambient or DJ-style sets stretch to 6-10.
- Speech / podcast transitions: 1-2 seconds
- Music joins (recommended): 3-5 seconds
- Ambient sets, slow-to-slow: 6-10 seconds
Four curves, four characters
Linear is the general default. Equal-power sine keeps total loudness steadiest mid-overlap — the first choice for music. Half-sine fades gently in and out for quiet moods. Logarithmic drops the outgoing track fast, for endings that drag. When unsure, start with equal-power sine.
Match levels before joining
Two recordings far apart in loudness expose the gap as a sudden jump inside the overlap. Normalize each track first, then crossfade. All processing runs locally in the browser.