Time Stretch Calculator

Calculate new audio duration when changing playback speed without affecting pitch. Essential for music production, DJing, and audio post-production.

Original Duration

Minutes

Seconds

Calculation Mode

Speed Percentage

BPM Change

Speed Percentage

Quick Reference:

100% = Original speed
200% = Twice as fast (half duration)
50% = Half speed (double duration)

About Time Stretch Calculator

Understanding Time Stretching in Audio

Time stretching is a powerful audio processing technique that allows you to change the duration of an audio recording without affecting its pitch. This technology has revolutionized music production, enabling producers and musicians to adjust tempos while maintaining musical integrity.

The Science Behind Time Stretching

Time stretching works by analyzing and manipulating the waveform of an audio signal. Traditional methods of changing playback speed would affect both timing and pitch (like playing a vinyl record at the wrong speed). Modern time-stretching algorithms can separate the temporal and pitch components of sound, allowing independent manipulation of each.

Common Applications

Music Production:

Matching tempos of different tracks in a mix
Creating rhythmic variations of samples
Adjusting recorded performances to fit a specific duration
Syncing music to video

Film and Video:

Fitting music cues to specific scene lengths
Creating slow-motion audio effects
Adjusting dialogue timing

Sound Design:

Creating atmospheric textures from short samples
Designing sound effects
Experimental sound manipulation

Time Stretching Methods

1. Granular Time Stretching:

Breaks the audio into tiny fragments (grains) and repositions them to create longer or shorter durations. This method works well for complex musical material but can introduce artifacts if stretched too far.

2. Phase Vocoding:

Uses frequency domain processing to analyze and manipulate the audio signal. Excellent for extreme time stretching but can sometimes produce a characteristic "phasey" sound.

3. Elastic Audio Algorithms:

Modern hybrid approaches that combine multiple techniques for optimal results depending on the audio material. These are commonly found in professional DAWs (Digital Audio Workstations).

Best Practices

Quality Considerations:
- Limit time stretching to reasonable ranges (usually within ±30% for best quality)
- Use high-quality source material
- Choose appropriate algorithms for your material (e.g., monophonic vs. polyphonic)
Workflow Tips:
- Always work with backup copies of your audio files
- Preview the results before committing to changes
- Consider breaking complex material into shorter segments for better control

How to Use This Calculator

Using Speed Percentage:

Enter the original duration in minutes and seconds
Select "Speed Percentage" mode
Enter the desired speed percentage (100% = original speed)
Click Calculate to see the new duration

Using BPM Change:

Enter the original duration in minutes and seconds
Select "BPM Change" mode
Enter the original and target BPM values
Click Calculate to see the new duration

Pro Tips:

For best audio quality, use smaller time stretching ratios
Consider using tempo-synced effects when working with stretched audio
Always monitor the audio quality after time stretching