We built Afterglow to keep feedback with the audio it refers to. It's an iPhone app for listening to demos and mixes, comparing versions, and writing timestamped notes.

You import audio files into a project and give each track a name. A demo and its later mixes can stay together, with separate notes for each version. Your library stays on your device. There's no account to create or cloud library to set up; the privacy page explains what the app stores and sends.

Notes at a specific time

Add a note while listening. It stays with that track and timestamp. Select the note later to play from that point.

The note editor starts at the position you chose. You can adjust the timestamp in that same editor before saving, including by moving through the waveform.

You can also label sections, such as a verse or chorus, to find them again without writing a comment.

Mix 2 paused at 0:34 with a note asking to keep the guitar from Demo 1, section labels, and the waveform below.
A note at 0:34 in Mix 2. The screenshots use an example project in the development app.

Compare versions

Keep a song's demos and mixes in one project. Each track has its own notes and playback position.

Comparison lets you switch between tracks, playing one at a time. Labels can mark the same section at different timestamps. If the chorus starts at 0:34 in one version and 0:36 in another, you can go to either directly.

The app doesn't automatically match loudness or tempo.

Moving to a shared label brings each version to that section; it doesn't link their playback positions as you listen. Notes remain attached to the version they describe when you import another mix.

Mix 2 and Demo 1 in comparison, each paused at its Chorus label: 0:34 in Mix 2 and 0:36 in Demo 1.
Chorus labels at 0:34 in Mix 2 and 0:36 in Demo 1.

Share your notes

Share notes as text with the project name, track name, timestamps, and labels included. You can send them through messages or email. The recipient doesn't need Afterglow to read them.

Labels appear as section headings with their timestamps, followed by notes in time order. An excerpt from the example project looks like this:

Borrowed light - Mix 2

Chorus (0:34)
-------------

0:34
Love this vocal. Could we keep the guitar from Demo 1 underneath it?

Audio is shared separately.

The iPhone share sheet open over Mix 2's notes, with options to copy the notes or save them to Files.
Copy notes or choose an app to share them.

Sharing notes sends a copy of the text. Later edits stay in Afterglow until you share again. To keep your whole library, including audio, sign in to sync it. The support page explains how.