Replaygain/ mp3gain testing

I have come across a discrepancy with mp3gain. I encoded an album to both mpc and mp3, then applied replaygain.exe to the mpc files, and mp3gain 0.6.3 to the mp3 files. I was interested to compare the album (or audiophile) gain applied by each program. The results are posted below.

Replaygain suggested a gain of –9.32 dB for the mpc files, and the analyse function of mp3gain suggested a gain of –9.43 dB for the mp3 files. So far so good.

However, when I ran the Album Gain function of mp3gain it produced a log as shown below, where it would seem that it has actually applied a gain of –6 dB. Does anyone know why this is?

Replaygain

Title | Album |
Level- | (Peak+)| Level- | (Peak+)|
Adjustment| Peak (Adjst)|Adjustment| Peak (Adjst)| Filename
----------+--------------+----------+--------------+---------------------------
-10.33 dB | 40393 (12297)| -9.32 dB | 40393 (13814)| Anastacia - Not That Kind - 01 - Not That Kind.mpc
-9.80 dB | 38577 (12483)| -9.32 dB | 40393 (13814)| Anastacia - Not That Kind - 02 - I'm Outta Love.mpc
-9.93 dB | 37991 (12111)| -9.32 dB | 40393 (13814)| Anastacia - Not That Kind - 03 - Cowboys & Kisses.mpc
-8.41 dB | 37585 (14273)| -9.32 dB | 40393 (13814)| Anastacia - Not That Kind - 04 - Who's Gonna Stop The Rain.mpc
-9.63 dB | 40063 (13220)| -9.32 dB | 40393 (13814)| Anastacia - Not That Kind - 05 - Love is Alive.mpc
-6.05 dB | 36179 (18028)| -9.32 dB | 40393 (13814)| Anastacia - Not That Kind - 06 - I Ask of You.mpc
-8.98 dB | 36397 (12944)| -9.32 dB | 40393 (13814)| Anastacia - Not That Kind - 07 - Wishing Well.mpc
-9.56 dB | 37379 (12434)| -9.32 dB | 40393 (13814)| Anastacia - Not That Kind - 08 - Made for Lovin' You.mpc
-10.18 dB | 38833 (12028)| -9.32 dB | 40393 (13814)| Anastacia - Not That Kind - 09 - Black Roses.mpc
-8.62 dB | 38735 (14358)| -9.32 dB | 40393 (13814)| Anastacia - Not That Kind - 10 - Yo Trippin'.mpc
-7.71 dB | 38237 (15739)| -9.32 dB | 40393 (13814)| Anastacia - Not That Kind - 11 - One More Chance.mpc
-8.12 dB | 36501 (14332)| -9.32 dB | 40393 (13814)| Anastacia - Not That Kind - 12 - Same Old Story.mpc

mp3gain analyse
16/01/2002 2:48:25 PM D:AnastaciatestAnastacia - Not That Kind - 01 - Not That Kind.mp3 RadiodB: -10.48 MaxAmp: 36899
16/01/2002 2:48:36 PM D:AnastaciatestAnastacia - Not That Kind - 02 - I'm Outta Love.mp3 RadiodB: -9.81 MaxAmp: 34801
16/01/2002 2:48:48 PM D:AnastaciatestAnastacia - Not That Kind - 03 - Cowboys & Kisses.mp3 RadiodB: -10.01 MaxAmp: 37996
16/01/2002 2:49:00 PM D:AnastaciatestAnastacia - Not That Kind - 04 - Who's Gonna Stop The Rain.mp3 RadiodB: -8.58 MaxAmp: 35379
16/01/2002 2:49:11 PM D:AnastaciatestAnastacia - Not That Kind - 05 - Love is Alive.mp3 RadiodB: -9.75 MaxAmp: 36516
16/01/2002 2:49:22 PM D:AnastaciatestAnastacia - Not That Kind - 06 - I Ask of You.mp3 RadiodB: -6.16 MaxAmp: 34319
16/01/2002 2:49:32 PM D:AnastaciatestAnastacia - Not That Kind - 07 - Wishing Well.mp3 RadiodB: -9.08 MaxAmp: 35504
16/01/2002 2:49:41 PM D:AnastaciatestAnastacia - Not That Kind - 08 - Made for Lovin' You.mp3 RadiodB: -9.62 MaxAmp: 35251
16/01/2002 2:49:50 PM D:AnastaciatestAnastacia - Not That Kind - 09 - Black Roses.mp3 RadiodB: -10.27 MaxAmp: 35562
16/01/2002 2:49:59 PM D:AnastaciatestAnastacia - Not That Kind - 10 - Yo Trippin'.mp3 RadiodB: -8.65 MaxAmp: 38091
16/01/2002 2:50:11 PM D:AnastaciatestAnastacia - Not That Kind - 11 - One More Chance.mp3 RadiodB: -7.81 MaxAmp: 35436
16/01/2002 2:50:24 PM D:AnastaciatestAnastacia - Not That Kind - 12 - Same Old Story.mp3 RadiodB: -8.28 MaxAmp: 38511
16/01/2002 2:50:24 PM D:AnastaciatestAnastacia - Not That Kind - 01 - Not That Kind.mp3 AlbumdB: -9.43
16/01/2002 2:50:24 PM D:AnastaciatestAnastacia - Not That Kind - 02 - I'm Outta Love.mp3 AlbumdB: -9.43
16/01/2002 2:50:24 PM D:AnastaciatestAnastacia - Not That Kind - 03 - Cowboys & Kisses.mp3 AlbumdB: -9.43
16/01/2002 2:50:24 PM D:AnastaciatestAnastacia - Not That Kind - 04 - Who's Gonna Stop The Rain.mp3 AlbumdB: -9.43
16/01/2002 2:50:24 PM D:AnastaciatestAnastacia - Not That Kind - 05 - Love is Alive.mp3 AlbumdB: -9.43
16/01/2002 2:50:24 PM D:AnastaciatestAnastacia - Not That Kind - 06 - I Ask of You.mp3 AlbumdB: -9.43
16/01/2002 2:50:24 PM D:AnastaciatestAnastacia - Not That Kind - 07 - Wishing Well.mp3 AlbumdB: -9.43
16/01/2002 2:50:24 PM D:AnastaciatestAnastacia - Not That Kind - 08 - Made for Lovin' You.mp3 AlbumdB: -9.43
16/01/2002 2:50:24 PM D:AnastaciatestAnastacia - Not That Kind - 09 - Black Roses.mp3 AlbumdB: -9.43
16/01/2002 2:50:24 PM D:AnastaciatestAnastacia - Not That Kind - 10 - Yo Trippin'.mp3 AlbumdB: -9.43
16/01/2002 2:50:24 PM D:AnastaciatestAnastacia - Not That Kind - 11 - One More Chance.mp3 AlbumdB: -9.43
16/01/2002 2:50:24 PM D:AnastaciatestAnastacia - Not That Kind - 12 - Same Old Story.mp3 AlbumdB: -9.43

mp3gain Album Gain (log of changes)
16/01/2002 2:37:07 PM D:AnastaciatestAnastacia - Not That Kind - 01 - Not That Kind.mp3 -6
16/01/2002 2:37:08 PM D:AnastaciatestAnastacia - Not That Kind - 02 - I'm Outta Love.mp3 -6
16/01/2002 2:37:08 PM D:AnastaciatestAnastacia - Not That Kind - 03 - Cowboys & Kisses.mp3 -6
16/01/2002 2:37:09 PM D:AnastaciatestAnastacia - Not That Kind - 04 - Who's Gonna Stop The Rain.mp3 -6
16/01/2002 2:37:10 PM D:AnastaciatestAnastacia - Not That Kind - 05 - Love is Alive.mp3 -6
16/01/2002 2:37:11 PM D:AnastaciatestAnastacia - Not That Kind - 06 - I Ask of You.mp3 -6
16/01/2002 2:37:12 PM D:AnastaciatestAnastacia - Not That Kind - 07 - Wishing Well.mp3 -6
16/01/2002 2:37:12 PM D:AnastaciatestAnastacia - Not That Kind - 08 - Made for Lovin' You.mp3 -6
16/01/2002 2:37:14 PM D:AnastaciatestAnastacia - Not That Kind - 09 - Black Roses.mp3 -6
16/01/2002 2:37:15 PM D:AnastaciatestAnastacia - Not That Kind - 10 - Yo Trippin'.mp3 -6
16/01/2002 2:37:15 PM D:AnastaciatestAnastacia - Not That Kind - 11 - One More Chance.mp3 -6
16/01/2002 2:37:16 PM D:AnastaciatestAnastacia - Not That Kind - 12 - Same Old Story.mp3 -6

Oops. Thanks for reminding me. That Analysis output routine is still outputting the mp3 "gain" change. The mp3 gain field is an integer, and changing it by +/- 1 makes a +/- 1.5 dB change. So mp3gain is, in fact, changing the gain in your files by (-6 * 1.5) = -9 dB, which is more what you'd expect.

I'll get that output changed so it's consistent with the rest of the program...

-Glen

Thanks Snelg.

Can I suggest that you put units after the numbers representing the analyse result or change in gain result in the log files; eg, -9.43 dB?

As you can see, Frank Klemm's replaygain does this, and leaves us in no doubt what is going on.

BTW Great program all the same!

Auditioning the mpc replaygain track and the mp3 gain adjusted track reveals that the mpc file is far lower in volume than the mp3 track.

So, apparently, even though both files are technically being adjusted in gain by about the same amount (see above post and logs), the mp3 file sounds OK, but the mpc file sounds crap - far too low in volume.

I am using Frank's replaygain.exe, mppdec.exe, latest Winamp plugoin. Is this the experience of other users?

What I am trying to achieve is a uniform album volume throughout a mixed collection of albums organised into folders of either mpc or mp3 files.

Hmm, I'll test this later, but if you're using the latest MPC WinAmp plugin, make sure the "headroom" -setting is 0dB.

Yep, that's the one: it was set at 6 dB (default setting). Thanks again.

In fact, after further testing, the whole thing works well with the "headroom" in mpc_in.dll (MPC WinAMP Plug-In 0.90b) set at -3 dB and mp3 left at mp3gain album changes.

The headroom function in mpc_in.dll then, works like a preamp, but from the reverse point of view?

Seems to be coming together very nicely.