Here is a video tutorial of how to sync full length audio tracks (i.e., songs) with a consistent tempo without the use of any plugins in FL Studio, such as Newtone.
This is useful for syncing up tracks for DJing in performance mode. You may also be interested in the DJ Performance Mode Templates that are set up for the APC40 and Launchpad.
There are other methods for syncing up audio using Newtone in a way similar to Ableton Live’s warp feature, but the method in the video works fine for most electronic music.
Once you have synced the audio file you may want to adjust the “Time Stretching” to the audio output you prefer.
The default is “Resample”, which works like a turntable and raises or lowers the pitch consistent with the raising or lowering of the tempo. This is the least resource intensive when manipulating the audio file, but if you raise or lower the tempo too much (usually within +-10 bpm of the original tempo) it starts to sound funny in my opinion. To maintain the original pitch, the “Pro Default” and “Pro Transient” options work best.
Also, one other consideration to make when using full length tracks in Performance mode for DJing is to separate the track into multiple parts as potential cue points.