Overlay two tracks
What Overlay two tracks actually does
Mixing two tracks is a level job, and the usual mixing filter quietly rescales its inputs by how many of them are currently playing. The result is a base that sits six decibels down for exactly as long as the overlay runs and jumps back the instant it ends, which is heard as a step in the middle of the mix rather than as a setting anyone chose. This page turns that rescaling off, so each level is the level asked for, and then says what the two peaks sum to, because summing without a rescale is what makes clipping possible. A limiter is offered as a decision rather than applied as a silent correction.
How to use it
- Choose the base first and the overlay second. Both appear on one timeline, the overlay drawn at the offset you set.
- Set each level, the start offset and any fade-in, and read the worst-case summed peak the page reports.
- Mix, then check the receipt read back from the produced file.
Useful for
- Put a music bed under narration that is already recorded.
- Drop a sound effect at a known second inside a longer recording.
- Layer an ambience track under dialogue without either being rescaled.
Limits worth knowing
- Exactly two files are used. A third is refused rather than silently ignored, which is what happened before.
- The two levels are summed as set, so a loud pair can pass full scale. The page reports the worst case and offers a limiter; it does not quietly turn anything down.
- For narration that should push the music down only while it speaks, the ducking tool is the right one; this page holds both levels constant.
Questions people ask
Are the files uploaded?
No. Decoding, mixing and the read-back all happen in this tab. The audio engine is fetched once and cached.
Why did my base used to get quieter and then louder again?
The mixing filter normalizes by the number of active inputs by default, so the base was halved while the overlay played. That normalization is now off.
What does the summed peak figure mean?
It is the worst case, the level reached if both peaks landed on the same sample. Real material usually peaks lower.