Reduce audio file size by creating a new MP3.
WAV · MP4 · M4A · FLAC · OGG · max 200 MB
Audio compression is useful when you want a recording to occupy less storage space or download more quickly. The AudioConvert compressor is intended for preparing a smaller encoded audio file; it should not be confused with dynamic-range compression, which changes the difference between loud and quiet sounds. If you recorded an interview, lecture or rehearsal as a large WAV file, an MP3 copy may be more convenient for sharing. Keep your original recording, particularly when you might edit it again later.
Bitrate is one of the main decisions when reducing an audio file's size. Lower values generally produce smaller files but leave less room for musical detail and subtle high-frequency sounds. Clear spoken-word recordings can sometimes remain perfectly understandable at relatively modest settings, while music containing cymbals, reverberation or dense instrumentation may benefit from a higher bitrate. The previously reviewed interface offered 96, 128, 160 and 192 kbps choices. Compare results by listening instead of assuming that one number is ideal for every source.
Begin with a copy of the source file. Choose a supported audio file and verify that its name appears in the file selector. Select a bitrate according to your purpose, then start processing. Leave the browser tab open while the operation runs. When the finished file becomes available, download it with a name that distinguishes it from the original. Open the MP3 in a separate audio player and listen near the beginning, middle and end. Quiet speech and complex musical passages are useful places to check for unwanted artifacts.
Re-encoding an already compressed MP3 can introduce further quality loss. This is particularly noticeable when the original has a low bitrate or has been repeatedly exported. Converting a poor recording to a higher bitrate will not restore missing information either. If the first result sounds harsh, metallic or unclear, return to the best available original rather than compressing the previous output again. A moderately larger file is often a worthwhile trade-off when the recording matters.
A file extension does not guarantee that the audio stream inside is supported. An MP4 container, for example, may contain a soundtrack encoded in different ways, or no usable soundtrack at all. If conversion fails, test the file in an ordinary player and then try a short, known-good source. Large files can also require substantial browser memory. Compression should make sharing easier, but its purpose is not to repair distortion, remove background noise or recover damaged audio.