AIFF to M4A for Music Production

Keep M4A out of the session itself. Lossy files inside a project mean the DAW decodes on import and re-encodes on export, and any processing you apply — EQ, compression, limiting — amplifies the codec's artifacts rather than hiding them. M4A is a delivery format: reference mixes, client sends, demos on a phone.

One trap catches people out: lossy encoding can push peaks slightly above the source, so a mix sitting exactly at 0 dBFS can clip once it becomes a M4A. Leave about -1 dBTP of headroom on the bounce you encode from — standard practice for masters, and it applies to reference files too.

Never send a lossy file to a distributor or streaming platform. They transcode whatever you upload into their own formats, so handing them an already-compressed file stacks a second lossy generation onto what your listeners actually hear. Deliver lossless; convert to lossy for humans.

The size drop is the point — around 8× less data, which is what turns an unsendable file into an attachment. Encoding straight from an uncompressed master means one lossy generation, not two — noticeably better than re-encoding from an already-compressed file.

AIFF files come from Logic Pro and GarageBand bounces, old iTunes rips, and Mac sample libraries. AIFF is uncompressed like WAV, so a four-minute song is 40 MB+ and won't attach to an email — which is the whole reason this conversion exists. M4A is the destination because it plays essentially everywhere — iPhone Voice Memos and every ordinary phone, browser, and player. Expect roughly 8× smaller: AIFF runs about 10 MB per minute, M4A about 1.2. Because AIFF is uncompressed, encoding to M4A here is the clean, single-generation case — the encoder sees the whole original signal, so this M4A is as good as the format gets.