Stretching and shrinking events

The Process > Length and Process > Fit to Time commands can be used to stretch or shrink a portion of a project. Process > Length lets you stretch or shrink the selection by a fixed percentage and makes the adjustment by altering the individual events. A value of 200 percent, for example, stretches the selection to twice its original length, while a value of 50 percent shrinks the selection to half its original length.

Process > Fit to Time stretches or shrinks the selection so that it ends at a specific time, expressed in either Measure:Beat:Tick (MBT) or Hours:Minutes:Seconds:Frames (SMPTE) format. This command gives you a choice of modifying the events or modifying the underlying tempo. This is useful when you want a portion of a project to have an exact length. The start time of the selection does not change, but the end time is altered as necessary to fit the required time interval.

Both of these commands offer the option to stretch audio clips along with the MIDI information. Sometimes you don’t want to adjust the speed of your audio.

Here are some examples:

If your project contains background music and a voice-over, you might want to change the tempo of the background music without altering the voice-over

If you’re trying to modify the speed of some MIDI tracks to match a sampled drum groove, you want to leave the audio unchanged

If your audio consists solely of sound effects, you most likely do not want to adjust them

Audio can be stretched or condensed up to a factor of 4 (e.g., it can be shrunk to as little as 25 percent of its original length, or expanded to as much as 400 percent of its original length).

You can also use the Process > Length command to alter only the start times or the durations of notes. For example, changing the durations of notes to 50 percent of their original length can create a staccato effect.

To stretch or shrink using percentages

1.	Select the events you want to change.

2.	Choose Process > Length to display the Length dialog box.

Figure 249. The Length dialog

3.	Choose to change the Start Times and/or Durations of selected notes by checking the boxes.

4.	If you want to stretch selected audio clips, check the Stretch Audio box. When this check box is enabled, the following two options become available:

Type. Choose the type of audio data you're stretching. Choose options based on the source material: single voice or instrument versus a group of instruments (ensemble or polyphonic), and how long you want to wait for processing to finish: better quality can take a long time if you're processing several tracks.

Formant scaling. Possible values range from -2.000 to 2.000 octaves. Formants give a voice its characteristic sound. If you find that changing the length of your audio changes the timbre too much, you can raise or lower the formant to try and maintain the characteristics of the sound

5.	Use the spinners or type in the desired percent change in length.

6.	Click OK when you are done.

SONAR modifies the length of selected events.

To stretch or shrink to a specific length

1.	Select the events you want to change.

2.	Choose Process > Fit to Time to display the Fit to Time dialog box.

Figure 250. The Fit to Time dialog

3.	Enter the desired end time in the New Thru box. Click Format to switch between MBT and SMPTE format.

4.	Choose one of the following:

Tempo Map. Choose this option if you want the tempo to change but not the duration of notes and events. For example, if your clip contains quarter notes, and you want those notes to stay quarter notes even though the elapsed time of the clip changes, choose Tempo Map. SONAR alters the tempo but not the events in the track.

Event Times. Choose this option if you want the tempo(s) to remain unchanged while note durations and event start times change.

Note: This option is unavailable if your selected data includes any Groove clips.

5.	If you want to stretch selected audio clips, check the Stretch Audio box. The following options become available:

Type (disabled unless Stretch Audio is checked). Choose options based on the source material: single voice or instrument versus a group of instruments (ensemble or polyphonic), and how long you want to wait for processing to finish: better quality can take a long time if you're processing several tracks.

Formant Scaling (disabled unless Stretch Audio is checked). The possible values range from ‑2.000 to 2.000 octaves. Formants give a voice its characteristic sound. If you find that changing the length of your audio changes the timbre too much, you can raise or lower the formant to try and maintain the characteristics of the sound

6.	Click OK when you are done.

SONAR modifies the length of selected events or changes the tempo map, as you requested.

High-resolution audio boosted by 6 dB when stretched using MPEX

When using a sample rate of 88.2 kHz or higher and performing any operation that uses MPEX time/pitch stretching, the stretched audio will be boosted by 6 dB.