Music app - half my songs are really quiet, within an album

I've just started using a Mcbook Air(Big Sur, 11.5.1, M1 chipset) after being a Linux/Windows user for years. I brought over my MP3 collection from my old Thinkpad and imported into the Music app.

For most albums, the tracks alternate between being normal volume and really quiet. Like 'I can barely hear it' quiet. I've tried switching on the Sound Check option in the Preferences, but it doesn't make any difference - it doesn't seem to do anything in fact.

If it was that one album was louder than another, I could maybe understand it, but for it to alternate within an album, I just don't understand. It's not an exact quiet-loud-quiet-loud-quiet-loud alternation btw - sometimes it might go quiet-quiet-loud-quiet-loud-loud for example. But, it's roughly a 50/50 split.

It also doesn't happen with every album - just most albums.

When i listened to them on the old laptop, they were all the same volume (with maybe a slight difference on an album-by-album basis but nothing like this).

I opened a "quiet" one and a loud one in Audacity and the peak db is the same in both, and if I listen to them out of Audacity they sound the same volume. So the issue is definitely with the playback in the Music app rather than the files themselves, unless there is some metadata Music is reading and adjusting the playback volume accordingly. If there was, though, i don't know why it would go up and down so much within an album.

Any ideas anyone?

EDIT - I downloaded Elmedia player and they all play fine in that - same volume. I would still prefer to fix them in Music though as it's a nicer interface.

Solution 1:

This turned out to be due to a setting on the individual MP3s which tells some players to turn them up or down. I don't know what the technical metadata field in the file is called but within the Music app it's called "volume adjust" and can be seen by right clicking on a track, choosing Get Info and then going to the Options tab.

In the problem albums, every track was set to either -90% or +100% in this 'volume adjust' setting. Obviously this setting is ignored in Audacity and Elmedia, the other player app I tried.

Fortunately it's possible to select multiple tracks (eg all tracks by a given artist or even all of your library I suppose), right click and Get Info, then go to the Options tab and set that 'volume adjust' to 0%.

As to how they got like that, I don't know. I have a vague memory of mucking about with a command line utility in linux for adjusting mp3 volumes, 10 or 15 years ago, and I suspect it was that which set these ridiculous volume adjust settings, which all the players I've been using have ignored, until now.