Harmonize is a function in DJ.Studio that facilitates smooth and automatic transitions between tracks without the need for manual beat-matching and crossfading.
Within seconds, Harmonize analyzes many possible combinations of your playlist and determines the optimal track order and transition placement, based on the options you choose.
At the end of the process, click the Harmonize button. Each click gives you a different order, so if you don't like the result, just click Harmonize again.
If you already have locked transitions in your mix, Harmonize keeps those tracks and transitions in place and works around them.
The Harmonize wizard
Pressing the Harmonize button opens a step-by-step wizard:
Key mixing: choose your harmonic mixing style
Order: set how track order is calculated
Mix on: choose how transitions are placed within each track
Transitions: fine-tune transition style, length, and mix points
Harmonize: alculates the best track order based on your tracklist and the settings you chose in the wizard; once the results are ready, you review them
Each step builds on the last: your choice on "Mix on," for example, changes which mix point options you set within that same step. The sections below walk through each step in order.
You don't have to follow the steps in order, though. The steps are optional; you can click Harmonize right away with the defaults, or click on any step in the sidebar to fine-tune it first.
Step 1: Key mixing
This step decides how strictly Harmonize sticks to harmonically safe transitions.
Fuzzy Mixing only accepts transitions that are likely to work harmonically. It sticks to safe, closely related keys, so nearly every transition it suggests will work. It's the low-risk choice: the resulting order holds up with little or no repair work, which is what you want when you're preparing a live set or a radio show and can't fix a clash on the spot.
Mood Mixing uses the same harmonic matches, plus bolder key changes that can lift the energy of your mix. Those moves sound exciting but are riskier: melodies can clash, so expect to check every transition and use hard swaps, careful timing, or stem separation. Mood is the better choice for a mix you're producing in the studio and can fine-tune in detail.
Not sure which to pick? Start with Fuzzy.
Step 2: Order
This step controls how the track order itself is calculated.
Harmonize priority slider (BPM ↔ Key): sets the balance between ordering by BPM, by harmonic key, or a mix of both. Moving toward BPM sets a tolerance in BPM (e.g. "4 BPM") for how much tempo variance is allowed between consecutive tracks.
Tempo direction: order the mix from slower to faster tracks (Ascending) or the reverse (Descending).
Lock tracks (first / last): lock a specific track to always be the first or last track in your mix. Place the track in your playlist first, then toggle it on here.
There is no separate control for how long Harmonize spends searching for the best order.
Step 3: Mix on
This step decides where inside each track a transition starts and ends, separately from how tracks are ordered. Your mix points are also set here, in the same place as the choice that determines them.
You'll see 4 options, each with a small preview of where it places a transition. Hover the info icon on an option to see what it's best for:
Bars (classic) Transitions at a fixed number of bars from the start and the end of every track. Best for predictable timing on any track, no phrase information needed.
Intro/outro overlap The outro of the outgoing track overlaps the intro of the next one, and that overlap sets the transition length automatically. Best for long, natural blends between tracks with clear intros and outros.
Phrase position Mixes in and out on the Nth musical phrase, counted from the start and the end of a track. Best for keeping every transition on a musical phrase boundary rather than an arbitrary bar count.
Song structure Mixes on the actual musical sections of a track: intro, build-up, drop, chorus, breakdown, and outro. Best for energy-driven sets where a drop needs to land on time.
About phrase analysis
Intro/outro overlap, Phrase position, and Song structure all rely on DJ.Studio having analyzed the musical phrases of your tracks, since intros, outros, and phrases are all phrase-level data.
If some tracks in your tracklist haven't been analyzed yet, DJ.Studio prompts you before continuing: a dialog appears saying how many tracks in your tracklist haven't been analyzed for phrases yet, which the mix theory you picked needs, with the option to Analyze them or Skip and fall back to bars for those tracks.
If no track in your mix has been analyzed at all, the three phrase-dependent cards (Intro/outro overlap, Phrase position, Song structure) grey out with the note "Needs phrase analysis: no track in this mix has been analyzed yet," only Bars (classic) stays selectable, and a line below the cards reads "All tracks will fall back to bar-based transitions until phrases are analyzed."
3.1 Mix points
Below the 4 cards, set your In-mix point and Out-mix point. What you see here depends entirely on the Mix on type you picked above:
Mix on type | In-mix point | Out-mix point |
Bars (classic) | Defines how many bars from the start of the new track the transition begins. Options: Auto, 0 bars, 1 bar, 4 bars, 8 bars, 16 bars. | Defines how many bars before the end of the current track the transition ends. Same option list. |
Intro/outro overlap | Defines how many bars from the start of the new track the transition begins, determined by the intro/outro length of the tracks. Only Auto; the other options are currently disabled. | Defines how many bars before the end of the current track the transition ends, determined by the intro/outro length of the tracks. |
Phrase position | Defines which phrase of the new track the transition starts on. Options: Auto, Phrase 1, Phrase 2, Phrase 3, Phrase 4... | Defines which phrase of the current track the transition ends on. Options: Auto, Last phrase, 2nd-to-last, 3rd-to-last, 4th-to-last... |
Song structure | Defines which section of the new track the transition starts at. Options: Auto, After intro, At first buildup, At first drop, At first chorus. Buildup and breakdown need rekordbox phrase analysis on a track in this mix. | Defines which section of the current track the transition ends at. Options: Auto, At outro, After last drop, At last breakdown. Same rekordbox note applies. |
For Intro/outro overlap, these dropdowns show "Auto" and are not clickable, the overlap itself sets them; the explanation is shown next to the fields. For every other Mix on type, both dropdowns work normally.
Step 4: Transitions
This step sets how the transitions are built, on top of the settings you already chose in the previous steps.
Mix on (read-only): a single line showing the mix on option you picked in step 3, for reference. To change it, go back to step 3.
Transition Style: pick from presets like crossfades, bass swaps, filtering, echoes, or your own saved presets.
Transition Length: the default bar length for transition frames.
Synchronize Tempo: when on, DJ.Studio automatically keeps the tempo of both tracks in your transitions aligned.
Save these settings for next time: enabled by default. When on, your transition settings here are remembered the next time you open Harmonize. When off, they apply only to this one Harmonize run, and tracks you add later keep your previously saved default.
Reviewing the result
Once Harmonize finishes calculating, you'll see your tracklist with match icons in the Match column showing the harmonic compatibility between each track and the one before it: green icons are good matches, yellow are close, and blue are further apart. See Harmonic Matches Explained for the full breakdown.
Re-Harmonize
You can re-harmonize your project at any point by clicking the Harmonize button again to reopen the wizard. Any locked transitions stay locked; unlocked tracks are free to be rearranged.
This is useful if you're partway through a mix and want a different order, or if you've added more tracks and want to re-check the fit.
How To Use Harmonize
Here's the full walkthrough from an empty playlist to a finished, harmonized mix, step by step.
Add tracks to your mix: press the "Add Tracks" button, or drag and drop tracks from your hard drive.
(Optional) Choose your first and last track by placing them at the start/end of the tracklist, ready to lock in step 5 below.
Press the Harmonize button to open the wizard.
Key mixing: choose Fuzzy or Mood mixing.
Order: set the BPM/Key balance and tempo direction, and lock your first/last track if wanted.
Mix on: choose how transitions are placed: Bars (classic), Intro/outro overlap, Phrase position, or Song structure.
Transitions: adjust transition style, length, and sync.
Press Harmonize and review your newly ordered mix. Each click gives a different order, so click it again if you'd like another option.
Solving track-matching issues
If any of your selected tracks don't match well, you'll see a red cross in the Match column.
Hover over the cross to reveal the Solve button, and click it. DJ.Studio searches your selected libraries for a track that bridges the gap, and you can add it directly to your mix to resolve the issue.
Frequently asked questions
What's the difference between the 4 Mix on types?
Bars (classic) and Intro/outro overlap place transitions based on bars and track structure timing; Phrase position and Song structure place transitions based on the track's actual musical phrases or sections.
See Step 3: Mix on above for the full breakdown.
Do I need to analyze my tracks before using Intro/Outro overlap, Phrase position or Song structure?
Yes, all three of these rely on phrase analysis. DJ.Studio prompts you to analyze the tracks that still need it before continuing: a dialog appears saying how many tracks in your tracklist haven't been analyzed for phrases yet, with the option to Analyze them or Skip and fall back to bars for those tracks.
Why aren't my harmonized tracks harmonically mixed?
Sometimes not all tracks end up harmonically mixed.
Common causes: you don't have enough closely related tracks in your playlist, one or more tracks has no compatible match in the playlist, or you set the Order priority toward BPM rather than Key.
Click the X icon in the Match column to have DJ.Studio search your library for a bridging track.
Is it possible to turn off Harmonize? I want to create the order myself.
DJ.Studio always places transitions according to your Settings > Transitions defaults. Setting In-mix point and Out-mix point to 0 bars gets you closest to no automatic overlap, and you can freely reorder tracks yourself in the playlist window.
Why can't I find the Harmonize button?
Harmonize isn't available in Mashup mode. Check the project name in the app header: if it says "Mashup," there's no Harmonize button. Choose "DJ mix" when creating a new project to access Harmonize.
Does Harmonize use Energy, in addition to BPM and Key?
No — Energy is subjective and varies by track segment and audience, so adding it as a third parameter would make the algorithm unclear. Harmonize uses BPM and Key only; you should still manually review your playlist order afterward.
Why don't the tracks fit harmonically after Harmonize?
Usually too few tracks (aim for at least 20–30 in a similar genre) or too much variance in key/BPM/genre across the playlist. Check the Match column for X's after Harmonizing, and click Harmonize again for a different order.
Why do the transitions sound bad after Harmonize?
Check your Settings > Harmonize defaults match your genre (e.g. short transition windows for disco, longer for techno), use stem separation for vocal-heavy genres like hip hop, and expect to manually fine-tune harder genres like Jazz. Harmonize proposes a starting point, not a finished mix.