Rhythm Synchronization

DynamDJ provides a couple of functions that allow you to synchronize the rhythm of two songs. This means that when two players are playing simultaneously, you can have DynamDJ automatically adjust the players' playback speeds and positions in a way that they fit to one same rhythm. It is, however, important to note that this technique does not work well on all songs, you can generally achieve the best results with a song that has a strong, regular rhythm on one side and a song with smoother rhythm of similar rate on the other side.

Configuring songs for rhythm synchronization

Before rhythm synchronization can be used, you need to inform DynamDJ about the rhythm of both songs. DynamDJ uses a simplified abstraction of rhythm which merely consists of a series of identical beats arranged throughout the song at equal distances. It is defined by two bits of information: the rate of the rhythm (i.e. the distance of the beats), given by a BPM (beats per minute) value, and the phase of the rhythm, that is, the distance of the first beat from the beginning of the audio file. Latter is needed by DynamDJ to adjust the players in a way the beats of both songs truly overlap, instead of only occurring at the same rate. Songs with changing or irregular rhythm are therefore not suited for DynamDJ rhythm synchronization.

To define the rhythm of a song, you need to have the song opened and playing in a player, and to have volume and fader set in a way that it is audible. Next, open the player's additional options to reveal the following controls.

The upper row, as focussed in this picture, is relevant for rhythm synchronization. For information about the other parts, see the player page. The text right-side the two buttons shows the BPM value of the current song. In this example, it is 116 bpm, if no rhythm has been set yet, no value is displayed. When you click the "set" button, the following window will pop up:

To define the rhythm, you need to click the tap button at each beat of the for some seconds, the longer the better. As noted above, you need to specify a regular rhythm, i.e. the gaps between the clicks on the tap button need to be equal and constant. During this process, the measured beats per minute value and phase will already appear in the window, you can stop clicking the button at any time to finalize the process. The tap button will continue to visualize the defined rhythm on its own after some seconds. (It turns lighter and darker repetitively at each beat).
If the visualized beats occur a bit earlier than the heard ones, drag the phase fine-tuning slider to the right; drag it to the right in the opposite case. If the defined rhythm seems to be slower or faster than the real one, adjust it using the rate fine-tuning buttons.
If the song's rhythm is to fast to be defined in this manner, one option is to adjust playback speed to a lower value in the player's audio parameters. Another option is to skip every second beat and to press the "x2" button afterwards to compensate it. It is probably necessary to readjust the phase with the corresponding slide after doing so.

You can safely close and reopen this window after the rhythm has been defined. The rhythm of a song will remain stored for as long as DynamDJ is running; if the song has been added to the library, it will be saved to the disk.

Rhythm synchronization using the fader

After the rhythm has been defined for two songs, the fader can be used to have DynamDJ perform automatic rhythm synchronization. For this to work, songs with a defined rhythm need to be open and playing in two neighboring players, and the fader needs to be positioned under one of these players. You can then animate the fader to the second player by clicking on the corresponding fader slider area using the right mouse button or while holding the ctrl key. (You can read more about this on the pages fader and parameter animation). Instead of only animating to the next player, the rhythm will first be synchronized by altering the target player's speed, then the fader will animate to it, and the speed will reset once cross-fading has finished.

Explicit rhythm synchronization

Rhythm synchronization with the fader is probably sufficient for practical usage in more cases, yet DynamDJ provides an interface for more advanced rhythm synchronization. It enables the following additional options: synchronizing rhythm without cross-fading, visualization of the rhythm of two players on a one-dimensional time line as an aid for manual synchronization, and synchronization of non-neighboring players.

To use this feature, at least two songs need to be open, and their rhythm needs to be set. For one of these players, click the "sync" button in the additional options of the player's controller. (see above) This player will be the one the rhythm of another player is synchronized from, which means that this player's speed won't be altered by automatic synchronization, but the other player's will. Therefore, you ought to synchronize from the player that can currently be heard (due to the fader position), so that the speed adjustment done before cross-fading is little noticeable. When the "sync" button has been clicked, this window appears:

The player chooser is where you can choose the player that will be synchronized from the player for which you opened this window. Latter is the one the arrow on the player chooser starts at, former the one it ends at. Only players whose song's rhythm has been set can be selected.
The rhythm visualizer shows the rhythm of both players. The background color of the two viewers represent which player is visualized by this viewer. Each bar represents a beat, when a player is playing, the bars of that player move to the left. The red line at the center is the present time, a bar reaches it at each beat of the song. The playback speed of players does not influence the speed at which the bars move in this visualization, instead, it affects the distance between the bars. If in the visualizer, each bar (or each second, third, etc. bar) of one player is located at the same horizontal position than a bar of the other player, the rhythm is synchronized. If this could be the case with the given bar distances, but the whole group of bars for one player is located too much to the left or to the right, the rate is synchronized, but the phase is not.
Synchronizing the rate can be done manually by adjusting the speed of a player (see the players page for more on this), the phase can be synchronized by pausing a player for short periods of time. The player's real time effects are useful to do this.

You can click the "Synchronize" button to have DynamDJ synchronize both rhythms automatically. The "Cross-fade" button acts the same way as described above (Rhythm synchronization using the fader): it first synchronizes the rhythm, then animates the fader towards the player selected in the player chooser, and smoothly resets that player's speed afterwards. Note that both functions always adjust that player's speed only.