Audio Trimmer

What it's for

Make quick changes to a sound file without installing an editor: cut it down to the part you want, play it backwards, change its speed, make it louder or quieter, fade it in and out, or turn stereo into mono, then save the result.

For example, when you want a 20-second clip from a recording for a presentation, open it here, set the start and end, add a short fade out, and save it.

How to use it

Choose a sound file (WAV, MP3, M4A, Ogg or FLAC, as far as this browser plays them), or drop it on the page. The waveform shows the sound, with the part you’re keeping in colour. Set Start and End in seconds, or click the waveform to move whichever is nearer.

Then, if you like:

• Play backwards reverses it, and Mono mixes the channels into one.
• Speed from 0.25 (four times slower) to 4 (four times faster), like a tape: the pitch goes down or up too.
• Volume change in decibels (6 dB is about twice the level), or Normalise, which makes the loudest moment −1 dB, just below the most a file can hold.
• Fade in and Fade out, in seconds.

Play the result plays it with the changes, Stop stops, and Save as WAV saves it, named like talk-edited.wav. The original file isn’t changed.

Example

In the Tone Generator, save a 2-second sine wave at 440 Hz, then open the file here.

The message says 0:02.00, mono, 48,000 Hz. Set Start to 0.5 and End to 1.5, tick Normalise, and Save as WAV: the saved file is one second long, and its loudest point is −1 dB.

Good to know

The result is always saved as a WAV file, which is larger than MP3 or M4A for the same sound. Changing the speed changes the pitch: there’s no keeping the pitch while changing the tempo. Volume changes that push a sound past the most a file can hold are clipped, which sounds harsh: use Normalise to avoid that.

The whole sound is held in memory, so very long recordings (an hour or more) may be slow or not open on some devices.