Are my assumptions of MP3Gain correct? Options

[Nazgulled]

Hi,

I've been using MP3Gain for some years now but up until recently I discovered something I was not aware and it's confusing me a little bit. I'm wondering if I have been using MP3Gain the way I thought I wanted... Sorry if this has been discussed before but I searched a lot (on these forums and Google) and couldn't find anything related.

I use MP3Gain so that when play my mp3s on my favorite media payer, they are normalized and play, roughly, with the same volume. I use Songbird and this media player has an option to "use audio normalization data" (with the options for track/album, I use track). To better explain things, I'll use an example...

I have this mp3 file, which, after analysis, reports a volume of 96.2.

When I set the target volume to 105 (just for example purposes), the mp3 final volume is 105.3 and the it contains this:

REPLAYGAIN_TRACK_GAIN=-16.26000 dB

When I set the target volume to 75 (just for example purposes), the mp3 final volume is 75.2 and the it contains this:

REPLAYGAIN_TRACK_GAIN=+13.84000 dB

If we do some basic math, we get this:

105.3 - 16.26 = 89.04 ~ 89.0
75.2 + 13.84 = 89.04 ~ 89.0

And the fact is, when I play this file with either target volume applied on Songbird with the normalization option enabled, I get the same volume level. If I disable the normalization option, I get different volume levels. The first one much louder than the latter, of course.

So, with my findings above, I conclude the following:

• The target volume will have zero impact on media players which support reading of audio normalization data (generated from MP3Gain at least, I believe this is called ReplayGain). However, the target volume will have impact on media players which don't support reading of audio normalization data (or if such option is disabled). For instance, Windows Media Player. This player will play the 105 file above louder than the 75 one.
• MP3Gain will always default to 89.0dB to set the replaygain track gain tag (which applications like Songbird read from) and there seems to be no way to change this.

Q1)
Are my assumptions of MP3Gain correct? I guess so because this is what I observed happening...

Q2)
What I want from MP3Gain are 2 things, a) normalize all mp3 to the same volume, b) increase that same volume a little bit.

Since MP3Gain always defaults to 89.0dB and there's no way to change it (or is there?) and since I want to have all my mp3s volume higher than 89.0dB, I guess my only option is to normalize all my mp3s with MP3Gain setting the target volume to my liking and don't enable the normalization option in Songbird. Right?

My real question here is, will all my mp3s still be normalized to that same target volume?

I would really appreciate some insight on this matter from the gurus out there... Thank you for your time.

This post has been edited by Nazgulled: Apr 6 2012, 01:47

[[JAZ]]

The Replaygain spec is defined so that the tags are always represented relative to 89dB SPL.

When your player is not replaygain-aware, the playback will be the one you've set with MP3Gain.
When your player is replaygain-aware, you have to tell the player that you want a different relative gain.

In foobar, this is achieved with "File->Preferences", Playback option -> Preamp with RG info.
With winamp, this is achieved with "Options->Preferences", Playback option, Replaygain -> Preamp with RG info (ok, i have it in another language, not sure how it is in english right now).