I only have a rudimentary understanding of how volume of MP3's is controlled, but I assume each frame of digital data contains a volume value. And some software can analyze MP3's and provide a relative volume reading, compared to a specific db, such as 87db. So one song might read as -2.7db, another -6.4db, and yet another -0.1db. These volume readings can then be saved by a software player (such as Media Monkey) and used when playing back the mp3's, so that their volumes match.

You can then use a program like Media Monkey to modify each MP3 so that it's average sound level is equal to the value you set, such as 87db, which is considered the highest level a CD will contain, before distortion may occur.

This is all fine and dandy, except I've modified songs from an entire album, and songs that bleed into the next (like ones that have a quiet intro piece that leads into a louder main piece) sound very jarring when listened to back to back.

Here's an example: Headless Cross from Black Sabbath tracks 1 and 2. Track 1 shows very low db level, while track 2 is at least 3-6 db higher. They blend together well like that. But modifying the tracks to equal 87db means the first track is much louder than usual and doesn't blend well into track 2 anymore.

So my question is this: Is there any software than can analyze an entire ALBUM's relative volume level, then adjust each track by the SAME db amount, so that relative differences between tracks remains the same?

Yes.

1) MP3Gain for mp3s.

2) WaveGain for WAV files.

3) Foobar2000 player for almost ALL formats .

Try the SEARCH function from this site with: mp3 gain

MP3Gain certainly does Album gain.

Thanks, everyone. MP3Gain is a godsend. The only drawback is that you have to make sure all your mp3's are stored in their associated album folders in order for Mp3gain to consider them part of the same album. A nice feature to add would be the ability to read the album tag inside the files. But I used Media Monkey to reorganize my files into folders, so it wasn't a big deal.

It took mp3gain about 2.5 hrs to analyze and volume adjust my 250 CD rips, but all things good are worth waiting for.

I was a bit confused as to the DB normalization level to use for the output. It defaults to 89db, which is quite a bit lower than all of my reported DB levels on the MP3's I ripped. So MP3gain basically lowered the volume on all mp3's down to closer to 89db.

If I tried to bump up the output DB from 89db, it showed clipping occurring on some tracks. The more I upped it, the more tracks showed clipping.

So how could an existing mp3 (with assumedly no clipping since it was ripped straight from CD) go from 98db to 91db and suddenly show clipping?!?!

The assumption is wrong. MP3 is a lossy process. You can rip a song with no clipping, encode it to mp3, and have clipping in the mp3.

FYI: the technology/algorithm used in all the linked apps is called "Replaygain".

edit: This thread contains some info about overcompression which may be helpful for you for deciding your target-dB level (89dB is the default).
http://www.hydrogenaudio.org/forums/index....showtopic=31140

- Lyx

1. It did not "suddenly" show clipping. Any clipping in existence at 91dB was definitely already there at 98dB. At a more extreme and harmful level.

2. There is no guarantee whatsoever that mp3 or wav files will not clip, simply because they are "ripped straight from CD". Especially these days. Neither is there any guarantee that adjusting them down to 91dB (or even to 89dB, for that matter) will remove all clipping, although 89dB is a safe level for most audio. That's why it is used as a reference.

3. In the case of an mp3 file, the distortion caused by clipping occurs when the mp3 is decoded back to wav format and either played audibly or written to disk, not when it is originally encoded. So, as long as your mp3's are adjusted to non-clip levels before being played or written to disk, the potential clipping of too-loud mp3's will cause no problems.

Regards,
Madrigal