traktor-harmonik

This is an add-on to the DJ software Traktor for improving its "harmonic mixing" capabilities.

Harmonic mixing is an innovative way to mix tracks together, creating perfect DJ sets. [ ... ] By mixing tracks that are in the same or related keys, harmonic mixing enables long blends and mash-ups. The goal is to eliminate key clashes.

Traktor already supports key shifting and in recent versions even automatic key detection. These are two important features needed for harmonic mixing. The third ingredient, key matching, is missing from Traktor however.

This tool adds the logic for computing compatible keys, and a visual aid for very easily matching the keys of two tracks. Each deck has an advanced key knob with three indicator LEDs instead of one:

• The blue LED represents the (implicit) key shift that is caused by changing the tempo of the track (time stretching).
• The green LED measures the amount of frequency shifting that is performed by turning the key knob. This value will be proportional to the degradation of your sound quality.
• Last but not least, the red LED indicates the mismatch between the current key and the keys that are compatible with the master track.

The secret behind the key matching is the Camelot system as explained here.

In the screenshot below, at the bottom of the screen, between the decks, you can see the advanced key knobs in action. Also, below the decks are two auxiliary key-mismatch-meters which display exactly the same as the red LEDs, but with more detail.

Traktor doesn't support add-ons in the true sense of the word. This tool is a standalone program that communicates with Traktor through some backdoors. However, in order to create the illusion that it is properly integrated in Traktor, the tool was given exactly the same look and feel as Traktor, so that you can almost seamlessly stack the windows of the two programs on top of each other. This was done in the screenshot above.

Setup

• To make sure that Traktor sends out a MIDI clock signal, follow these instructions.
• In order to get hold of the track info of your decks, add the DENON HC4500 to your list of controllers and set Out-Port to Traktor Virtual Output. By doing so we trick Traktor into believing the HC4500 is connected, and it will start broadcasting the track info of decks A and B, encoded in MIDI. (Credits for this clever hack go to Siytek).
• A MIDI controller is required. For each deck, choose a knob on your controller and assign it to the key shift functions in both Traktor and the add-on. In the add-on, assigning controls can be done with the blue buttons below the key knobs.
• All songs must be properly tagged with key information. Newer versions of Traktor have a key detection feature to help you with that. There is also external software that can do this, such as Mixed In Key or Rapid Evolution.
• All songs have to be in your Traktor Library. (And moreover, the collection.nml file must be stored at the default place, namely /Users/<your name>/Music/Traktor/).

Limitations and pitfalls

• Currently this software is Mac only. Windows users are on their own for now. Please contact me if you are a Windows programmer and you need some help to make it work.
• When you launch the application, it will automatically try to launch Google Chrome. Make sure you extract the app from the .dmg file before launching it, because otherwise Chrome will crash. If you don't have Chrome, just use your favourite browser instead and go to http://localhost:8080. Note however that I have only tested with Chrome, it might look slightly different in other browsers.
• While launching, the application will also try to position the window at the bottom of the screen. It tries to make itself as small as possible, in order to leave enough space for Traktor itself. Just maximize the window to the see everything.
• Make sure you feel confident enough playing with this software before using it live! On slow computers it may have a negative influence on Traktor's sound quality.

For developers

Prerequisites

The following build tools are required:

• Leiningen
• Sass
• make

After cloning this repository, run the following commands to bootstrap ClojureScript:

lein deps
lein git-deps
(cd .lein-git-deps/clojurescript && script/bootstrap)

Building

To build the JavaScript and CSS:

make js css

Running

To fire up a server at http://localhost:8080:

lein run

Distributing

To build a Mac OS application bundle:

make app

and to package it in a disk image:

make dmg

License

Copyright © 2014 Bert Frees

Distributed under the Eclipse Public License, the same as Clojure.