Change Audio Speed Without Changing Pitch — Free Online Tool

Time-stretching is the process of changing the speed of audio without affecting its pitch. This is different from simply changing the playback speed, which would also raise or lower the pitch.

Our tool uses ffmpeg's atempo filter — a phase vocoder algorithm that analyzes the audio in overlapping frames and reconstructs it at the new speed while preserving all frequency content.

• Speed up 1.5x — audio plays 50% faster, same pitch
• Slow down 0.75x — audio plays 25% slower, same pitch
• Double speed 2.0x — audio plays twice as fast, same pitch

• Practice — slow down complex solos or fills to learn them note by note
• DJ preparation — speed up samples to fit a higher-BPM project
• Podcast editing — speed up recordings slightly to reduce duration
• Language learning — slow down speech for easier comprehension
• Music production — time-stretch samples to fit your project tempo