How to crossfade two songs so the transition sounds smooth

A crossfade is the moment when one song fades out while the next one fades in, so the music never stops. Done well, nobody notices it. Done badly, you hear two drum patterns fighting or a sudden dip in volume. This guide explains what makes a crossfade sound smooth and shows how to build one, for free, in your browser with MixSongs.

What you need

• Two songs as audio files: MP3, WAV, FLAC, M4A, OGG or AIFF.
• A browser on a laptop or desktop (Chrome, Edge, Firefox or Safari).
• Five minutes. No account and no installation are needed, and your files are not uploaded.

Step 1: Add both songs in sequence

Open app.mixsongs.app and drag the first song onto the page. Then drag the second song in and choose in sequence – after the last song in the import card. MixSongs places the second song so it overlaps the end of the first and draws a starting crossfade with volume checkpoints: the first song’s line goes down while the second song’s line goes up.

Press Space to listen. That default fade is a reasonable starting point. The rest of this guide is about making it great.

Step 2: Choose where the transition happens

The single biggest factor in a smooth crossfade is where it happens, not how long it is.

• Fade out of a phrase ending. Most songs move in 8- or 16-bar phrases. Start lowering song A at the start of its last phrase or its outro, not in the middle of a vocal line.
• Land song B on a downbeat. Let the second song reach full volume exactly when a new section starts: the first chorus, the drop, or the first beat after its intro.
• Avoid two vocals at once. If both songs have vocals in the overlap, the listener hears a jumble. Overlap an instrumental outro with an instrumental intro whenever you can.

In MixSongs, drag the second clip left or right on the timeline to move the whole transition. To line things up precisely, switch the grid to bars, type the tempo into the BPM box, and keep snap on, so clips and checkpoints lock to bar lines. Hold Alt while dragging to place them freely.

Step 3: Pick the right fade length

There is no single correct length, but these ranges work:

Situation	Fade length
Similar tempo, instrumental intro/outro	8–16 seconds
Similar tempo, vocals near the edges	3–6 seconds
Different tempos	1–3 seconds, or fade during a drum-free section
Hard energy change (ballad → dance)	Short fade, or a quick cut on the downbeat

MixSongs plays each song at its original tempo (it never time-stretches, which keeps quality perfect), so long overlaps between songs at different tempos let the beats drift apart. Shorter fades hide that.

Step 4: Shape the curve with checkpoints

The default crossfade is a straight line on each side. Because the volume line in MixSongs is made of checkpoints you can drag, you can reshape it:

1. Click on a track’s volume line to add a checkpoint.
2. Drag a checkpoint to change its time and level. Hold Shift to change only the level.
3. Drag the line between two checkpoints to move both together.
4. Double-click a checkpoint to delete it.

Three shapes worth knowing:

• Equal blend. A goes from 100% to 0% while B goes from 0% to 100% over the same span. Neutral and safe.
• Late fade. Keep A at full volume until B is already halfway in, then drop A quickly. The new song feels like it “takes over”.
• Duck and swap. Lower A to around 40% when B starts, hold it there under B’s intro for a bar or two, then fade it out. This is how radio presenters talk over intros.

The waveform in each clip redraws as you move checkpoints, so you can see the fade you’re about to hear. You can keep editing while the song plays.

Step 5: Check the loudness of the overlap

When two loud masters overlap at high levels, their peaks add up. MixSongs mixes in 32-bit floating point, so nothing distorts internally. The master LIM (limiter) button, on by default, catches peaks above −1 dBFS on playback and in your export. If the transition sounds crowded rather than loud, dip both songs a little in the middle of the fade: add a checkpoint on each line at about 80%.

Step 6: Export the mix

Click Export. If your sources were lossless files, choose FLAC 24-bit or WAV; if they were MP3s, MP3 320 kbps is the sensible choice (a bigger format can’t restore detail the MP3s never had). Rendering happens in your browser, so even long mixes never leave your computer. Read more in WAV vs FLAC vs MP3.

Common problems and fixes

“I hear a dip in the middle of the fade.” Linear fades on both sides can feel slightly quieter in the middle. Raise both lines a bit at the midpoint (add a checkpoint at about 70% on each).

“The drums clash.” The tempos differ, or the beats aren’t aligned. Shorten the overlap, or move it to a section without drums. With AI stem separation you can fade out one song’s drums early and keep its vocals. See AI stem separation.

“The second song starts too abruptly.” Add a short fade-in on the clip itself by dragging the small handle in the clip’s top corner, or start its volume line a little lower.

Try it now

Open MixSongs, drop in two songs, and use the checkpoints to try each shape above. It’s free, private, and takes less time than reading this guide. For a full multi-song set, continue with how to make a DJ mix online.