AIFF to M4A for Podcasts

Podcasters hit this specific conversion because Logic Pro and GarageBand bounces is where the AIFF came from — a remote guest, a field recording, a clip — and AIFF is uncompressed like WAV, so a four-minute song is 40 MB+ and won't attach to an email. For a show you need M4A, so the AIFF-to-M4A step is part of the edit, not an afterthought.

M4A is what you publish — Apple Podcasts, Spotify, and every RSS-based host expect it. The order matters more than the format: record and edit on a lossless file, and encode the M4A once, from the finished episode. Converting early means every later edit sits on top of lossy audio and your export adds another generation on top of that.

Podcast bitrates are lower than most people assume, deliberately. 128 kbps stereo is the widely used standard, and 64–96 kbps mono is entirely respectable for pure speech — it roughly halves the download for every listener, which adds up across a back catalogue and matters to anyone on limited mobile data. Reserve 192 kbps and above for shows where music genuinely carries the experience.

Mono is the decision most worth revisiting. If your episode is voices with no meaningful stereo image — which describes most interview and solo shows — mono at 96 kbps is perceptually equivalent to stereo at 192 and half the size. Publishing stereo by default is a habit, not a requirement. And archive the lossless edit: social clips, best-of segments, and fixes should always be cut from that, never from the published file.

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.