Learn That Guitar Solo. Speed It Up Later.
There’s a John Mayer lick that’s been driving you crazy for three weeks. At full speed it’s a blur of notes and you can’t figure out the fingering. Slow it down to 0.5x and suddenly each note is distinct, you can hear the hammer-ons, the slides, the ghost notes you were missing.
Practice at half speed until your fingers know the pattern. Then bump it to 0.75x. Then 1x. That’s how working musicians learn parts, and this tool exports the slowed-down version as a file you can loop on your phone during practice.
The Other Direction
You’ve got a 3-hour audiobook and a 2-hour road trip. Speed it up to 1.5x and it fits perfectly. A 90-minute lecture at 2x becomes a 45-minute review session. Spoken word sounds totally fine sped up, you don’t lose comprehension until you push past about 2.5x, and even then it depends on the speaker.
How It Works
Upload an audio file, set the speed anywhere from 0.5x to 4x, and download the result. The server uses FFmpeg’s audio processing filters to change the tempo while preserving pitch as much as possible. That means slowed audio doesn’t get unnaturally deep, and sped-up audio doesn’t go chipmunk.
The output comes back in the same format you uploaded. MP3 in, MP3 out.
Steps
- Upload your audio file.
- Set the speed with the slider or preset buttons.
- Click Change Speed.
- Download.
Who Uses This
Musicians learning songs. This is the classic use case. Slow a difficult passage to 0.5x, learn it note by note, gradually speed back up. Guitar players, piano students, drummers, bass players, everyone does this.
Podcast bingers. If you subscribe to fifteen podcasts and work full-time, listening at 1.5x or 2x is the only way to keep up. Speed up the entire episode and save yourself hours per week.
Students reviewing lectures. A 90-minute recorded lecture at 1.5x takes 60 minutes. At 2x, 45 minutes. You’ll retain the material just as well, research backs this up for familiar topics.
Language learners. Native speakers talk fast. Slowing to 0.7x lets you hear individual syllables, catch pronunciation details, and distinguish words that blur together at full speed. Way more effective than replaying at 1x over and over.
Transcriptionists. Slow the audio to 0.75x and type along. Fewer pauses, fewer rewinds, faster turnaround.
Quick scanning. You’ve got a 2-hour meeting recording and need to find the five minutes where they discussed the budget. Skim at 3-4x until you hear the right topic, note the timestamp, then go back and listen at normal speed.
Trim the file first with the Audio Trimmer if you only need a section. The Metronome can help you verify tempo targets when practicing music.
FAQ
Does the pitch change? The processing maintains original pitch as much as possible. You won’t get the Alvin and the Chipmunks effect at 2x, or the horror-movie deep voice at 0.5x.
What speeds are typical? 0.5x-0.75x for music practice. 1.25x-2x for spoken word. 3x-4x for quick scanning.
What’s the output format? Same as your input. Upload MP3, get MP3 back. Upload WAV, get WAV back.
Does the file size change? Yes, proportionally. Double speed = half duration = roughly half file size. Half speed = double duration = roughly double file size.
Any length limit? No hard cap. Longer files take more processing time, but it handles normal audio lengths fine.