01 — The tool
Change audio speed without changing pitch
The free Loudness.ai Audio Speed Changer adjusts a recording's pace while keeping voices and musical notes at their original pitch. Slow down audio to hear a difficult passage, or speed up a spoken recording for a shorter version. The multiplier ranges from half speed to double speed.
The duration display updates with your selected multiplier. At 0.75×, a 60-second recording becomes 80 seconds; at 1.5×, it becomes 40 seconds. Prepare a preview, compare it with the original and export the result. Use the Audio Pitch Changer when you want to transpose notes instead of changing their timing.
02 — How it works
How to slow down or speed up audio online for free
Choose your recording
Open MP3, WAV or another supported audio file. Listen to the original so you can judge the pace and identify a section that needs a closer listen.
Set the speed multiplier
Move the speed slider or choose a preset. Try 0.75× for a slower passage or 1.25× for faster speech. Check the new duration before preparing the preview.
Compare and export
Click Preview change, then switch between Original and Preview. Choose MP3 or WAV, set quality and sample rate, and export when the pace and sound are suitable.
03 — Practical uses
Adjust the pace of music practice, speech and lessons
Music practice
Slow down a rapid phrase to hear the notes and rhythm. For repeated practice, save the slower version and open the Audio Looper to repeat the section you are learning.
Spoken recordings
Speed up audio from a lecture, voice note or interview when you want a shorter listening version. Make a modest change first, and check that unfamiliar words remain understandable.
Voiceover timing
Fit a narration take to a shorter or longer section of video. Start with a small adjustment and listen for changes in the voice's texture, especially on sustained vowels and breaths.
04 — Frequently asked questions
Audio Speed Changer questions
Does slowing audio lower its pitch?
This tool changes timing while preserving pitch. A slower version should keep the same musical notes and voice register. Compare the preview with the original to decide whether the chosen speed sounds natural.
How do speed and duration relate?
New duration equals original duration divided by the speed multiplier. A 2× version is half as long, while a 0.5× version is twice as long. The editor displays the calculated duration.
Can I change the speed of just one passage?
The speed setting applies to the recording opened in this tool. Use the Audio Cutter to save the passage first, then adjust that clip's speed and export it.
What should I listen for in the preview?
Check fast consonants, drum attacks and held notes. Larger timing changes can make these sounds less natural. Try a smaller adjustment if the result becomes rough or the words become difficult to follow.