As of August 2010, all of Behringer's DJ mixers--with the exception of the Pro Mixer DX2000USB--have BPM (beats per minute) counters for easier mixing. Besides helping you mix songs with different tempos, the BPM counters on Behringer's DJ mixers also make it possible to synchronise your sampler, effects, crossfader and external drum machines via MIDI.
Use "Auto BPM." Ensure this function is activated. When active, the "Auto BPM" push-button is yellow and the BPM indicator flashes in the display. If the "Tap Mode" is active--indicated by the "Auto BPM" button shining blue--press the "Auto BPM" button for longer than a second to activate "Auto BPM."
Activate "Tap Mode." Ensure this mode is activated--when active, the "Auto BPM/Tap" push-button shines blue--and the BPM indicator shows "Manual." Tap the "Tap" push-button at least two times to the rhythm of the music, which results in a constant BPM value. Try listening in on the original signal using the headphones.
Adjust the BPM at any time by tapping.
Watch the BPM of the track on channel 2, on the left.
Watch the BPM of the track on channel 3, on the right.
Use the crossfader to mix from one track to another.
Watch the displays for the BPM of each channel.
Use the "Sync Lock" button to limit the range of possible tempo values within a song. Press this button once the counter has caught and displayed a realistic value.
Use the "Beat Assist" button to set the beat counter's tempo manually, similar to the "tap tempo" function on other mixers. Pressing the button three times in time with the track will set the beat counter and its display at that tempo.
Determine and lock the tempo of two different tracks with "Sync Lock" or "Beat Assist."
Look at the "Tempo Difference" LED display to see the tempo difference between channels 1 and 2. The LED shows the degree of the tempo difference by deflecting to the right (if channel 2 track is faster) or to the left (if channel 3 track is faster).
Adjust until the centre LED light up, which indicates the tempos are equal. When the display moves to the left or right, the corresponding channel is out of sync. The synchronisation of channel 1 and 2 is shown in the "Time Offset" LED, below the "Time Difference" display.
Exit the "Sync Lock" or "Beat Assist" mode by pressing the "Sync Lock" key on both channels.
Without a music signal (or one that's too quiet), the DDM 4000s BPM value flashes on the display. In addition, the message "Low Level" appears on the display. The BPM value also flashes with the message "Uncertain" when it cannot clearly identify the beat.