Why is my podcast too quiet on Apple Podcasts and Spotify?

Because it's quieter than the loudness podcast apps expect. Don't count on the listener's app to fix it: whether an app evens out loudness depends on the app and its settings. Deliver the episode at about −16 LUFS (−19 for a mono file), with peaks under −1 dBTP.

The number that matters

Loudness is measured in LUFS: how loud the whole episode sounds on average, weighted the way our ears hear. Apple's guidance for podcasts is about −16 LUFS, give or take 1 dB, with true peaks no higher than −1 dBTP (Apple Podcasts audio requirements). It's a sensible target for the other apps too. A home recording straight from the mic is often −25 to −30 LUFS: clearly too quiet.

Why just turning it up doesn't work

Raising the whole file by 10 dB also raises the loudest laugh by 10 dB, and it clips. A podcast has to be evened out first (quiet sentences up, loud moments down), and only then brought to −16 with a limiter catching the last peaks.

How to fix it

  1. Level the voices: by hand with volume automation, with gentle compression, or with a leveller that follows the speech.
  2. Set the loudness: raise the whole episode until it measures −16 LUFS integrated.
  3. Limit the peaks to −1 dBTP with a true-peak limiter.
  4. Check the exported file, not the project: MP3 encoding can move peaks a little.

Gain Curve does all four: pick Podcast as the target, press Make it ready, and it measures the exported file exactly and adjusts until it's on target.

Mono or stereo?

A mono file sounds as loud at −19 LUFS as the same voice in stereo at −16, because loudness meters add the two stereo channels together. That's why −19 is the usual target for a mono file. Mono at 64 or 96 kbps is a sensible size for a speech-only show.

More on loudness numbers: what LUFS should my audio be for each platform.

Paul Voia-Tipei, PVT Studio