DJ edits by hand: loop choice, equal-power seams, and both ends at once

Radio edits are built to hit the hook in the first fifteen seconds, which is exactly wrong for a booth: you need eight or sixteen bars of groove to mix into before the song announces itself. The classic fix is an intro edit — a clean phrase looped ahead of the track — and it is one of the few DJ tools you can build honestly with your ears and a waveform.

§How to make a DJ intro edit

  1. Drop the trackDecoded and edited locally; nothing uploads.
  2. Select a loopable phraseDrag on the waveform around a steady, vocal-free groove — whole bars, starting on a downbeat.
  3. Test the loopLet it cycle. If the groove hiccups at the wrap, nudge the edges with the arrow keys until it disappears.
  4. Build intro, outro, or bothPick the repeat count and render; the Both ends mode does the full DJ copy in one pass.
  5. A/B against the originalFlip between them loudness-matched, then download the WAV.

01Loops are bars, not seconds

A DJ intro works because it is musical time: whole bars of a steady phrase. At 124 BPM a bar of 4/4 lasts 4 × 60 ÷ 124 = 1.94 seconds, an 8-bar phrase is 15.5 seconds, and four repeats of it buy you just over a minute of mixable runway. Those numbers come from the tempo, which is why the selection should be nudged by ear until the loop breathes in bars.

The failure mode is arithmetic: a selection 30 ms short of the true bar leaves every repeat 30 ms earlier than the last, and by the fourth pass the groove has slid 120 ms — audibly late. Concatenation accumulates whatever error the selection carries; the loop test exists to catch it while it is still one repeat small.

02Equal power at every seam

Butting two pieces of audio together clicks; fading them linearly dips, because at the midpoint both sides sit at half amplitude and the summed power drops about 3 dB. The equal-power crossfade fixes the dip: the outgoing side follows a cosine curve and the incoming a sine, so the two gains squared always sum to one and the acoustic power stays constant through the joint. Every seam this tool renders — between repeats, and between the loop and the song — uses it.

Length still matters: 10–20 ms is a click-killer on a tight drum loop, while 60–100 ms smooths a phrase with reverb tails at the cost of slightly softened transients.

03Audition the joint, not the edit

A four-minute render is a terrible way to judge a 15-millisecond decision. The Seam zoom mode magnifies the exact splice — the end of your loop meeting its own beginning — with the crossfade curves drawn over the two waveforms, and plays just the second around the joint on repeat.

Ears judge a short seam far better than a long edit: if the joint survives five seconds of looped scrutiny, it will survive a club. If it thumps, the zoomed view usually shows you why — a transient caught mid-fade, or edges that missed the zero crossing.

04The working copy has two ends

A track you actually gig needs runway on both sides: an intro to mix into and an outro to mix out of. The Both ends mode takes two selections — an intro loop and an outro loop, each with its own repeat count — and renders the full DJ copy in one pass: repeats, song, repeats, every seam equal-power.

Set the intro loop from the first clean groove and the outro loop from the last one, and the render is the version of the song your library actually wanted.

05A/B without the loudness lie

Crossfaded repeats of a loud section can leave an edit measurably louder or quieter than its source, and a level difference reads as a quality difference — the louder file wins the comparison for the wrong reason. The A/B mode measures the integrated loudness of both files and flips between them matched, each side remembering its own position.

What you are listening for is structure: does the intro hold attention for four repeats, does the seam into the song land, does the outro die with dignity. Volume is removed from the vote.

06Your ears set these loop points. The studio heard the whole song.

On a tight, quantized groove, ear-set loop points and a zero-crossing snap will carry you — that is exactly what this page is for. What it cannot know is where the bar truly starts, because it never analyzed the song. SongStrip in the studio did: bar-locked loops that never drift, plus GPU-separated stems, so the intro edit can be built from just the drums and bass with nothing to cancel and nothing to slide. Build the quick edit here; build the clean one there.

Take it further in the studio — start free with 3 full packs, no card needed.