Hi everyone,

I've got a wee bit of a problem...

A few weeks ago I realised I'd been damaging some of the music I keep for years by normalising it. I did this because I didn't know about amplify in my ignorance. I'm now in the process of setting everything right. It's a bit of a drag, but I'm halfway through my film scores now.

However... I have one folder with over 700 files. I know I normalised some of them in the past, but definitely not all of them. Is there a way for me to immediately discover which tracks hat were? I don't want to re-rip 700 tracks if I can avoid it.

Truth be told: You will never know.

You would need the original file and use something like Foobar2000 to compare both versions.
This means downloading everything again or ripping everything again from CD.

There is "somewhat" of a database out there for "Dynamic Range" of music, but this applies to Albums only.
Not by track.
And the database mostly consists of "normal" music from band artists on hit radio stations.
The probability of finding the albums you've normalized to do a cross-reference are insurmountable.

Viewing spectrograms don't show anything. At all.
You would need to list your entire archive and ask others to post spectrograms of their music that hasn't been normalized.

You can use SoX for statistic analysis (-stat -stats), or any other program that analyzes audio for loudness peaks or whatever arbitrary stat you can come up with in your head.
It won't matter unless you have a clean, original file to cross-reference.

Sorry to say, but your best bet is to rebuild your archive.

Okay, thanks. I'd better get started...

Just to add, if you normalized whole CDs and not track-by-track, normalisation will not have 'harmed' your collection. It may even be beneficial when you pass it through a good amp. However, the variations in audio levels when a track finishes and another starts and is supposed to be seamless, you may well notice glitches at those points.

Thanks. I hate normalise now because it takes away all the volume differences within a track as well. No wonder my Anglican hymns sounded so weak...

it takes away all the volume differences within a track

It depends how you normalize.
There's multiple ways to normalize audio.
You can read more here:
How To Normalize Audio - Why Do It? Everything You Need To Know (http://www.learndigitalaudio.com/blog/normalize-audio)

I don't like to apply normalization to the encoding process, but I'll scan with ReplayGain which only adds a tag about normalization during playback (not encoded).
Foobar2000 uses ReplayGain.