normalizing 320kbps mp3 audio, should or should I not help

Replaygain is probably your best bet.

I use MediaMonkey, which has ReplayGain built in. Typically, ReplayGain adds metadata to the track without altering the original audio data. http://en.wikipedia.org/wiki/ReplayGain

 

"Alternatively, a tool can amplify or attenuate the data itself and save the result to another, gain-adjusted audio file; this is not perfectly reversible in most cases." When listening on my computer, I prefer NOT to do this and let MediaMonkey use its Volume Leveling feature. 

 

Most DAPs/mp3 players have similar ReplayGain support. Some have a separate Volume Normalizing feature (e.g. Sony players). I circumvent the Sony version because I also use MediaMonkey to transfer songs to my DAP. Then what I do is set up a transfer rule to adjust the track volume (permanently) on transfer. This means on my player the volume has been permanently changed, but on my computer the song contains the original audio data. I'm not sure if this is better or worse for audio quality, but it's damn convenient. 

 

Some swear by Foobar, but if you can't tell, I love MediaMonkey. 

Edited by seekadds - 1/26/12 at 12:27pm

What software are you using to play your music? iTunes has Sound Check, which does the same thing as ReplayGain.

I use MP3gain and it works perfectly. The volume of the MP3 file is changed, but it can be reversed with MP3gain. You can try it on a few albums.

 

Remember to not use "track gain" on albums. First import the album that you want to change the volume on, then mark the songs and choose "analyze album gain". After the is done, choose "album gain". I usually set the volume to around 89dB. That gives me more headroom and I can raise the volume on my MP3 player instead of the songs themselves having ear deafening volume.

 

MP3gain will analyze the volume of all songs in a folder, so if you have artist X on your HDD with subfolders containing albums 1, 2, 3 etc, each album will get a different value. If you have all the albums of an artist in the same subfolder, the songs will get one value, so I would not recommend that. The best thing is to have an artist folder and then one folder for each and every album.

 

http://mp3gain.sourceforge.net/

 

If you strictly listen to albums, I would advise you to not use track gain on an album folder. Track gain will adjust the volume of each song to the value that you have set, i.e. in your case 91db. The dynamics of the album will be lost that way. It is best to use album gain on an album since it will keep the dynamics of the album and not make soft and quiet songs as loud as more up-tempo songs.

 

Have you removed tags from the louder album? There might be replay gain tags that mess everything up. Best to check that first. MP3tag is a good software that gives you an overview of tags on MP3 songs.

If there are no replay gain tags, you could always make the volume a bit lower than on the other albums. Like 90 or 89 db...

 

You can also use dbpoweramp with it's replaygain plugin, which will actually set both track & gain levels for each file, so you can select say , track level when shuffling tracks, or album level when playing single whole albums. I know Rockbox as an example gives you options to set how/when you wish replaygain to work. The great thing about this is that it only changes the level flag inside the id tag, so the actual mp3 isn't physically being changed.

This is also what I use (though I use the aacgain version that also supports aac files) and it's really important to use album gain and do gain adjustments on a per album level or you kill all dynamic variation within an album

It can make it both better or worse depending on the dB value you use. I normally go for 89dB.

It might be, probably depends on the individual track.

I must confess that I have never fully understood the clipping indications in mp3gain