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Starting with version 1.11, Mixxx comes with a new ultra-precise BPM and beat detector.
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The beat grid gets adjusted after track analysis has finished. Manual
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adjustments are unnecessary in many cases because Mixxx knows where the beats are.
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adjustments are redundant in many cases because Mixxx knows where the beats are.
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BPM and beat detection is a complex operation. Depending on your computer, the track's bitrate and duration
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this may take some time. By default Mixxx analyzes the complete track, however, it will not analyze more than
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10 minutes of audio. To accelerate BPM detection on slower computers, a "Fast Analysis" option is available
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in the preferences. If enabled, the BPM is computed by analyzing the first minute of the track. In most
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cases this does not affect the BPM detection negatively because most modern dance music is written
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10 minutes of audio. To accelerate BPM detection on slower computers, a "Fast Analysis" option is available.
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If enabled, the BPM is computed by analyzing the first minute of the track. In most
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cases this does not affect the BPM detection negatively because most of today's dance music is written
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in a 4/4 signature, i.e., the distances between the beats are constant.
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.. figure:: ../_static/mixxx-1.11-bpm-prefs.png
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:alt: Mixxx preferences - Setting up recordings
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:alt: Mixxx preferences - BPM settings
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:figclass: pretty-figures
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By default Mixxx assumes that your music follows a constant tempo, i.e., a 4/4 signature.
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Correcting beat grids
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The table below summarizes the beat detection settings:
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+----------------------------------------+-------------------------------------------------------+
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| Option | Description |
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+========================================+=======================================================+
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| Enable Fast Analysis | If enabled, BPM detection results from the first |
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| | minute of audio. |
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+----------------------------------------+-------------------------------------------------------+
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| Assume constant tempo | If enabled, Mixxx assumes that the distances between |
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| | the beats are constant. If disabled, the raw beat grid|
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| | obtained by the analyzer is presented. The latter is |
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| | appropriate for tracks with variable BPMs |
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+----------------------------------------+-------------------------------------------------------+
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| Enable Offset Correction | Prevents beat markers from being placed incorrectly. |
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+----------------------------------------+-------------------------------------------------------+
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| Re-analyse beats when settings | If enabled, Mixxx over-write old beat grids from |
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| change or beats already present | Mixxx 1.10.0 and earlier. Moreover, it will re-analyze|
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| | the BPM if your beat detection preference change. |
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+----------------------------------------+-------------------------------------------------------+
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Correcting Beat Grids
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---------------------
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- If the BPM has been computed wrong
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--> How to get the perfect beat grid
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There may be situations where BPM and beat detection do not result in a proper beat grid. This
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does not necessarily originate from a false computed BPM value. In most cases, the BPM value
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is correct but the analyzer has failed to find the first "real" beat. Consequently, the beat markers
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are shifted, i.e., they are placed somewhere between two correct beats. To re-adjust the beat grid
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cue the track before a real beat and click the "gate" button illustrated in the figure below.
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.. figure:: ../_static/correcting_beat_grid.png
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:alt: Mixxx preferences - Correcting beat grids
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:figclass: pretty-figures
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If the detected BPM value is not sufficiently accurate, the corresponding beat grid is not accurate, too. A deviation of
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0.02 BPM units is enough -- compared to the correct BPM -- to notice an unaligned beat grid for long tracks (e.g., a club mix).
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In other words, your beat grid may look aligned for the first one or two minutes but you will notice the tiny error in placing
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the beat markers soon. Finding the correct BPM, however, is easy in many cases. Just follow the note below.
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.. note:: If the detected BPM value is not sufficiently accurate but very close to an integer value,
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try to set the BPM value manually to the integer.