Convert AIFF to MP3
AIFF is Apple's uncompressed audio container - the Mac equivalent of WAV. Files are large (10 MB per minute at CD quality); MP3 output typically compresses 8x while preserving everything a consumer playback chain can reproduce. See Audio codecs explained for when uncompressed / lossless / lossy each make sense.
What actually changes
AIFF (Audio Interchange File Format) was designed by Apple in 1988 as part of their Interchange File Format (IFF) work, and remains the uncompressed-audio format of choice inside Logic Pro, Final Cut Pro, and older Mac music-production workflows. Structurally it's very close to WAV - both carry PCM samples inside a container header - but AIFF uses big-endian byte order, WAV little-endian. The .aif and .aiff extensions are equivalent (Mac Classic used .aif for the 3-character-limit filesystem, macOS uses .aiff).
Wave decodes the AIFF file to PCM samples through the ffmpeg-wasm engine and re-encodes to MP3 at 192 kbps VBR through libmp3lame. Because the source is uncompressed, decoding is free - the samples in the file ARE the audio - and the LAME encoder produces an MP3 that's roughly 12% of the AIFF's size while remaining transparent on any consumer playback chain. A 60-minute AIFF at 16-bit / 44.1 kHz stereo drops from about 630 MB to 85 MB.
AIFF-C (AIFF Compressed) is an extension of the format that supports codec-compressed audio inside an AIFF wrapper - typically µ-law, A-law, or MACE compression from the pre-2000s Mac era. Wave decodes AIFF-C too. Modern Apple workflows almost never write AIFF-C - the industry moved to Apple Lossless (ALAC) for compressed lossless and to raw AIFF for interchange.
The specific reason people convert AIFF to MP3 is a Mac-workflow story. Logic Pro exports final mixes as AIFF by default (a legacy setting from the format's pro-audio roots), Final Cut Pro exports audio stems as AIFF, and many mastering handoffs still ship as AIFF. The delivery-format target for those workflows - to podcast platforms, to streaming services' user-upload flows, to listeners - is almost always MP3. Wave handles the last-mile step without shipping the audio to a cloud converter.
Three steps.
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Step 1
Drop the .aiff or .aif file onto the card.
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Step 2
Wave inspects the PCM samples and confirms Decode-and-re-encode.
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Step 3
Convert. Save the MP3.
Answers, specifically.
AIFF vs WAV - does either convert better?
Neither. Both are uncompressed PCM under different container conventions. LAME produces indistinguishable MP3s from equivalent AIFF and WAV sources.
Logic Pro AIFF exports?
Yes. Logic's default 24-bit / 48 kHz AIFF exports decode cleanly. The MP3 preserves everything audible on consumer playback.
Final Cut Pro audio stems as AIFF?
Yes. Wave handles multi-channel AIFF sources by downmixing to stereo before the MP3 encode using standard SMPTE fold coefficients.
AIFF-C (compressed AIFF)?
Yes. The AIFF-C variants Wave sees today are almost always older µ-law or A-law encoded audio; both decode through ffmpeg-wasm.
24-bit or 32-bit float AIFF?
Yes. LAME handles higher bit depths transparently through its float pipeline; the MP3 preserves everything a consumer playback chain can reproduce.
Do AIFF metadata chunks carry over?
Basic title / artist tags stored in the NAME chunk transfer to ID3v2 in the MP3 output. Marker chunks (Logic Pro region markers, Pro Tools clip metadata) don't map to MP3 - they're dropped.
Sample rates above 48 kHz?
88.2, 96, 176.4, 192 kHz - all decode. The MP3 output resamples to 44.1 or 48 kHz; the extra sample-rate headroom exceeds the audible range for human hearing anyway.