My attention has recently been turning to Niente, which hasn't had a new release in something like 5 months. I'm planning a new release for it at the start of April, though there are a few new floors being fitted throughout the house in the meantime, so that schedule might slip!
Anyway: I couldn't but help notice the more than 3000 folders of music in my collection that Niente thought could do with a volume boost. Since I've only got about 17,000 recordings in total, that's quite a sizeable chunk that is, in some way, less than ideal. It arises from the fact that I was ripping CDs in 1999 and only got round to writing volume-boosting technology into Semplice in around 2019! Short of going to each sub-volume-boosted folder, one by one, and running Semplice there to apply a retroactive volume boost, this wasn't going to be fixed any time soon: thirty or forty would have been fine; three thousand or more, less so!
A long time ago, I promised myself (and this site) that I would never write a batch volume updater, because volume updating means physically modifying FLAC files... and I wasn't going to batch modify my music collection to that extent, with perhaps less than predictable results. Well, I've been using volume technology on new rips for at least five years at this point and I've seldom been irritated or surprised with the results ...and I also have very good backups of my music collection, should anything go horribly wrong! So I've relented and I've just written a short article describing how to run a new script that will apply appropriate volume boosts to FLACs in bulk.
The usual caveats apply: volume boosts are calculated on a per-folder basis, not a per-track one. We wouldn't want to make the quiet, slow movement of a symphony hugely louder whilst barely touching the allegro furioso movement: that way madness lies. So all movements of the symphony in a folder are analysed and if the quiet movement could be boosted by +9dB and the loud movement by +0.6dB, only the +0.6dB is applied, meaning all tracks stay the same relative loudness, though the absolute loudness of all of them will have increased a bit. Volume boosts are also calculated never to introduce distortion, in all cases. In fact, so keen to avoid distortion is it that, when it calculates that a +3dB boost will bring a folder to maximum loudness, it then knocks that back a bit and only applies a +2.5dB boost: 0.5dB is always held back from any boost, for safety's sake.
The new script asks you to set a limit below and beyond which the batch updater won't try and boost volumes: I recommend something like a 1 - 9 range: in other words, don't waste time boosting things that are only 1dB short of maximal volume anyway; and don't try and boost recordings which are more than 9dB away from maximal loudness. Peak volumes quieter than around 9 tend, in my experience, to have been deliberately mastered to mask or hide recording defects: boost them to any significant extent and those defects become horribly audible! But anything between 1 and 9dB short of maximal loudness is probably a reasonable candidate for a modest volume boost. The new article gives an example of the quietest recording in my collection boosted by a modest amount and then by the maximum possible amount -and the version with the maximum possible boost sounds ghastly! Stick to a 1 - 8 or 9 setting for the new script, however, and I think you'll get a useful boost to the base volume of your collection without introducing ghastliness.
Obviously, audiophiles will abhor the idea of fiddling around with the volumes in a carefully-mastered audio track at all. That's fine: volume-boosting is something such people should avoid. I find it useful, however, because I don't live in an anechoic chamber and so sometimes need to hear things above ambient noise levels. I also find it useful because I don't play CDs, but 'works' ripped from a CD: recording engineers tend to set recording levels that produce a pleasing result across an entire CD, resulting in less-than-optimal volumes for some of the individual works on it. Volume boosting is just me correcting the 'average volume' issue introduced on some CDs that regard the envelope as more important than the letter (information) it contains!
I will not be building this into Niente in the future: Niente is a monitoring tool, not a fix-it one. I'm happy to release it as a standalone example of a particular fix-it script, however.