The master player is the lower right component of the main window. It provides some global controls of the audio produced by DynamDJ. The master player is in fact not a player by itself, it is a regroupment of the outputs of the various players as a whole.
The VU meter visualizes the global volume and balance of the audio. If the bars become too wide, the audio is too loud and may sound distorted. Volume and balance of the audio output can be adjusted using the sliders below it. The mute button can be clicked to temporarily mute audio output; clicking it again will reset the volume to the previous one. The three buttons beside it are used to open the library, preferences and help, respectively. Those functions are available in the menu bar as well.
The master player also allows you to record the audio produced in DynamDJ to a file. You can enter a name for this file in the recording file name field, its destination folder and format can be set in the preferences. The default destination is the desktop. Clicking the record button will start or stop recording.