Editing a clip’s tempo map

Each audio clip has an internal tempo map, which makes it possible to synchronize the audio clip with the project’s global tempo map.

Sonar automatically creates a tempo map for each audio clip. In some cases, Sonar can detect the wrong tempo. For example, Sonar might detect a tempo of 120 BPM when the actual tempo is 240 BPM, or a beat may be mapped to the wrong transient. You can easily remap the tempo map, if necessary.

Sonar provides a convenient graphical interface for editing a clip’s tempo map.

You should make sure a clip’s internal tempo map is correct before using any of the tempo-related commands in the AudioSnap palette.

The following figure shows what a Sonar-generate clip tempo map might look like.

Figure 327. You can edit the internal tempo map of each audio clip.

The following controls are available when editing a clip’s tempo map:

Beat markers. Each detected beat has a corresponding beat marker. You can remap a beat marker by dragging the marker to any active transient marker. When a beat marker has been moved, it turns red and becomes “anchored” to the assigned transient marker. An “anchored” beat marker is a marker that has been edited as opposed to a beat that Sonar detected. To “un-anchor” a beat marker, double-click the marker.

Average Tempo. This list shows the average tempo candidates: original, 0.5x and 2x. Sonar will do its best to detect the correct average tempo, but a clip can often have multiple potential tempos (60 BPM, 120 BPM, 240 BPM, etc.). If Sonar is unable to detect a tempo, Average Tempo will be set to Original, which is the project’s tempo at the location the clip was recorded or imported. If you change the Average Tempo setting, all clip tempo changes are adjusted to scale.

This list also contains the Set Clip Tempo From Project command, which copies the project’s tempo map to the clip’s tempo map. This allows the project’s measure boundaries to align with the audio clip.

Beats per measure. This list lets you specify the number of beats per measure. The value range is 2 to 14, and the default value is 4.

To edit a clip’s tempo map

1.	Select the clip or clips you want to edit.

2.	Click the Edit clip tempo map button on the AudioSnap palette.

A simple tempo map guide appears above the clip, indicating where Sonar has mapped the bars/beats of the clip.

3.	If the Average Tempo list does not show the correct tempo, select the correct tempo.

4.	If the Beats per measure box does not show the correct number of beats, specify the correct number of beats per measure.

5.	Starting from the beginning of the clip, inspect the beat markers above the clip. If any beat marker is mapped to the wrong transient, drag the beat marker to the correct transient.

Figure 328. Drag beat markers to edit the clip tempo map.

 

Note 1: Beat markers can only be dragged to active transient markers. If you need to drag a beat marker to a position that doesn’t have a corresponding transient marker, first insert a new transient marker at the desired position. For details, see To insert a new transient marker. You can also use the Merge and Lock Markers command to merge transient markers from other tracks. This is useful, for example, if one track contains beats 1 and 3 and another track contains beats 2 and 4. For details, see To copy transient markers from one track to another track.

Note 2: If you hold down the CTRL key when you drag a beat marker to the left, the original beat marker and all subsequent beat markers will be renumbered accordingly. If you hold down the CTRL key when you drag a beat marker to the right, all subsequent beat markers will be moved by the same number of transient markers.

The clip’s tempo map is recalculated and the dragged beat marker turns red to indicate it has been “anchored” to a new transient. An “anchored” beat marker is a marker that has been edited as opposed to a beat that Sonar detected. To “un-anchor” a beat marker, double-click the marker.

If a beat marker is dragged to a transient marker that is already assigned to a later beat marker, Sonar will automatically re-number all subsequent beat markers accordingly.

A beat marker cannot be dragged to an earlier transient marker if that transient is already assigned to a beat marker.

6.	To hide the tempo map guide, click the Edit clip tempo map button on the AudioSnap palette again.

Tip: You can also enable/disable Edit clip tempo map from the transient marker context menu.

To audition an audio clip when editing the clip tempo map

When you are editing a clip’s tempo map, you may frequently need to audition the audio to make sure you are positioning the beat markers at the correct transients.

1.	Right-click the clip tempo map (above the clip) where you want to audition the clip, and keep the right mouse button pressed.

Sonar creates a one-measure selection, starting from one measure before the position clicked. The selected time will gradually increase the longer you keep the mouse button pressed.

2.	Release the right mouse button.

Sonar auditions the selection.

 

See:

Using global tools on AudioSnap transient markers

Editing transient markers

Using the AudioSnap palette

Synchronizing audio and the project tempo

Fixing timing problems in audio clips

Extracting MIDI timing information from audio

General editing

Using the Pool

Algorithms and rendering