Track Analysis, Track Gain, Album Analysis, Album Gain: MP3Gain’s Four Buttons, Explained

New users stare at MP3Gain’s four operations and ask the same question: which one do I actually click? The short answer is that there are really two buttons — Analysis and Gain — and each has a pull-down menu with a Track mode and an Album mode. This page explains what each of the four does, mechanically, so you can click the right pair every time. For the full beginner walkthrough, start with how to use MP3Gain.

The pattern: analyze first, gain second

Every MP3Gain job is two passes over the same files:

• Analysis = measuring. MP3Gain decodes each file, measures how loud it sounds (the ReplayGain method), and writes the results into the columns. Analysis never modifies your audio.
• Gain = applying. MP3Gain takes the numbers from the analysis and rewrites the gain value in each MP3 frame. This is the only step that changes files — losslessly, and reversibly via the undo record it stores in the tags.

Track and Album are simply the two ways of grouping that work: per song, or per set. Combine the two passes with the two groupings and you get the famous four.

Track Analysis: measure each song on its own

Where: the Analysis button’s main click (its pull-down also offers Album Analysis and Clear Analysis).

Track Analysis measures every file independently and fills in two columns: the file’s current Volume and its Track Gain — the exact adjustment that would bring that one song to the Target “Normal” Volume (89.0 dB by default). It also flags any file that would clip if raised all the way. Run it on a mixed folder of downloads and you will see wildly different Track Gain values row by row: +8.5 for a quiet old rip, −6.0 for a loud modern master. That spread is your volume problem, made visible.

Album Analysis: measure the set as one album

Where: the Analysis button’s pull-down menu.

Album Analysis measures the same files but answers a different question: “if everything in the list is one album, how loud is the album as a whole?” It fills the Album Gain column with a single shared value — the adjustment that brings the album’s overall level to the target while leaving the differences between its tracks untouched. The quiet intro stays quieter than the finale, exactly as the artist sequenced it. The catch: Album Analysis believes everything in the list belongs together. Run it on a folder of unrelated singles and the “album” it computes is meaningless.

Track Gain: apply each song’s own correction

Where: the Gain button’s main click.

Track Gain applies every file’s individual Track Gain value. Each song lands on the target loudness regardless of its neighbours, which is precisely what you want for shuffle play, mixed playlists, DJ folders, and downloads accumulated from a dozen sources. Because the adjustment happens in the file’s frames — in 1.5 dB steps — the correction is as close to the calculated value as the MP3 format allows, and it travels with the file to every player.

Album Gain: apply one correction to the whole set

Where: the Gain button’s pull-down menu.

Album Gain applies the single Album Gain value to every file in the list — all of them up (or down) by the same amount. The album’s internal balance is preserved; only its overall level changes, like turning the volume knob once for the whole record. Use it for complete albums, classical recordings, and live sets. The Gain pull-down also hides a third option, Constant Gain, which applies a fixed dB change you type in yourself, ignoring analysis entirely — a specialist tool, mostly useful for manual corrections and for reversing a known change.

Which pair do I click?

Match the analysis to the gain you intend to apply — Album Gain needs Album Analysis numbers behind it, and Track Gain needs Track Analysis. If you analyzed one way and changed your mind, just run the other analysis; it costs a minute and overwrites nothing but figures.

The two classic misclicks

• “I clicked Analysis and nothing changed.” Correct — analysis is a measurement, not a fix. Nothing changes until a Gain button applies the numbers.
• “One song on the album is still quiet.” After Album Gain, that is by design: the album’s internal differences are preserved. If you truly want every song equally loud, that folder needed Track Gain instead — re-run it with Track Analysis and Track Gain, and see our undo guide if you want a clean slate first.

One last piece of the interface worth knowing: because MP3Gain stores its analysis in each file’s tags, reopening a processed folder shows the old numbers instantly. The buttons are how you work; the columns are how you check. Master those, and the program has no mysteries left — the remaining choices are about settings, not buttons.

The pull-down extras, for completeness

Two more entries live in those menus and are worth recognizing so they never surprise you. Clear Analysis (Analysis pull-down) wipes the calculated figures from the list — and from consideration for the next gain pass — without touching the audio; use it when you have changed the target volume and want a visibly fresh start. And the status line at the bottom of the window narrates every pass: which file is being measured, which is being written, and when the job is done. On a long batch it is your progress bar and your error log in one — if a file cannot be read or written, that is where MP3Gain says so, and the troubleshooting hub is where those messages lead.