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Soundcheck in iTunes 12

I'm in the process of editing and EQing my music collection, then uploading it to iTunes. I have quite a few songs so it'll take some time to do them all.


I also have quite a few live albums, which poses a problem. Seeing how everything was made loud, my EQing process slightly helps take the loudness out.


But where I amplify a single song in Audacity to a -0.5db peak. the album as a whole must peak at -0.5db, so whatever point is highest, the rest will be amplified to whatever point. So if one song peaks at, -10.0db and another is at -13.0db for example, the -10.0db song will be amplified to a peak at -0.5db while the other will peak at -4.5db.



My questions is, what will soundcheck normalize the songs to? I tried a live album once and turned on soundcheck and the numbers were all over the place (which I expected but I still wasn't sure)...

Windows 7

Posted on Apr 23, 2015 7:08 PM

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9 replies

Apr 23, 2015 7:16 PM in response to ToolAZBay

ToolAZBay wrote:


I'm in the process of editing and EQing my music collection, then uploading it to iTunes. I have quite a few songs so it'll take some time to do them all.


I also have quite a few live albums, which poses a problem. Seeing how everything was made loud, my EQing process slightly helps take the loudness out.


But where I amplify a single song in Audacity to a -0.5db peak. the album as a whole must peak at -0.5db, so whatever point is highest, the rest will be amplified to whatever point. So if one song peaks at, -10.0db and another is at -13.0db for example, the -10.0db song will be amplified to a peak at -0.5db while the other will peak at -4.5db.



My questions is, what will soundcheck normalize the songs to? I tried a live album once and turned on soundcheck and the numbers were all over the place (which I expected but I still wasn't sure)...


Tool,


I am pretty sure that iTunes analyzes the songs one at time, and does not look across other tracks in the same album. That seems to be borne out by the results of your experiment.

Apr 23, 2015 8:01 PM in response to ed2345

ed2345 wrote:


Tool,


I am pretty sure that iTunes analyzes the songs one at time, and does not look across other tracks in the same album. That seems to be borne out by the results of your experiment.


Ok, here is the result of my little experiment.


Audioslave - Live EP


Track Title - Audacity Peak - iTunes file volume

Set It Off: -0.5 / -0.5

Doesn't Remind Me: -0.6 / -0.4

Gasoline: -1.5 / +0.5

Out Of Exile: -0.8 / -0.2


So the track "Set It Off" was where the album peaked as a waveform. Now what exactly does the iTunes volume mean. Set It Off shows a -0.5db, but Gasoline is at a +0.5db. Does it mean all activity peaks/limits at -1.0db? In this case? Because the studio content I tried (3 tracks) stayed at their peak of -0.5db...

Apr 24, 2015 4:32 AM in response to ToolAZBay

Now what exactly does the iTunes volume mean.


ToolAZBay,


I have reason to believe that older versions of iTunes used something like a simple analysis of the peak volume. In those days, SoundCheck performed poorly (it was a common complaint in this forum), and many users turned to 3rd party volume normalization tools such as iVolume and MP3Gain.


It appears that iTunes has made improvements in this area recently. To me, playback sounds much more even, and SoundCheck complaints on this forum are down. The support doc states that Sound Check "computes characteristics of their playback volume" which certainly hints that it is something more sophisticated than a simple peak analysis.


Is that consistent with what you are seeing?

Apr 24, 2015 11:15 AM in response to ed2345

ed2345 wrote:


I have reason to believe that older versions of iTunes used something like a simple analysis of the peak volume. In those days, SoundCheck performed poorly (it was a common complaint in this forum), and many users turned to 3rd party volume normalization tools such as iVolume and MP3Gain.


It appears that iTunes has made improvements in this area recently. To me, playback sounds much more even, and SoundCheck complaints on this forum are down. The support doc states that Sound Check "computes characteristics of their playback volume" which certainly hints that it is something more sophisticated than a simple peak analysis.


Is that consistent with what you are seeing?


I don't know for sure because I almost used to never use or have a need for Soundcheck. But like I said, studio tracks (or stand alone live tracks) stay at -0.5db after I edit them and amplify them to a -0.5db peak in Audacity. It's just the short live album I posted up before regarding what was the peak in Audacity, then what the volume data showed in iTunes..

Apr 24, 2015 1:10 PM in response to ToolAZBay

OK, you got me curious, and here is my little experiment.


1. Started with a softly mastered classical MP3 that was in at iTunes showing +11.9 dB.


2. Used Audacity to up it by 3 dB. Added that new track to iTunes, and it shows volume correction of +0.5dB.


3. Used Audacity to take that second track back down by 3 dB, which should end up pretty much the same as what I started with. iTunes analyzes this at +3.5 dB, which is perfectly explicable based on track 2 but bears no relation to track 1.


I cannot explain it except for the obvious observation that iTunes is doing something other than just analyzing the peak.

Apr 25, 2015 6:38 AM in response to ed2345

ed2345 wrote:


OK, you got me curious, and here is my little experiment.


1. Started with a softly mastered classical MP3 that was in at iTunes showing +11.9 dB.


2. Used Audacity to up it by 3 dB. Added that new track to iTunes, and it shows volume correction of +0.5dB.


3. Used Audacity to take that second track back down by 3 dB, which should end up pretty much the same as what I started with. iTunes analyzes this at +3.5 dB, which is perfectly explicable based on track 2 but bears no relation to track 1.


I cannot explain it except for the obvious observation that iTunes is doing something other than just analyzing the peak.

Hm, that is odd. But usually stand alone songs stay their volume in my case. For example, a song that peaks at -0.5db in Audacity, has the volume info in the file at -0.5db.


So I tried my concerns with a larger live album sample, Alice In Chains "Live" I converted the WAV files I used (I have the CD) to 192 AAC with Soundcheck OFF. (Although I have switched it on in the past but before this test, so I don't know if that makes a difference) So here's how things turned out for this live album.


Track Title / Peak In Audacity / Volume Info on iTunes


Bleed The Freak / -0.5 / -0.5

Queen Of The Rodeo / -4.8 / +3.8

Angry Chair / -1.4 / +0.4

Man In The Box / -1.4 / +0.4

Love, Hate, Love / -0.7 / -0.3

Rooster / -2.6 / +1.6

Would / -2.1 / +1.1

Junkhead / -0.7 / -0.3

Dirt / -1.1 / +0.1

Them Bones / -3.2 / +2.2

God Am / -2.0 / +1.0

Again / -2.4 / +1.5

A Little Bitter / -2.4 / +1.4

Dam That River / -1.6 / +0.6


What this means now, I have no idea at all..

Apr 25, 2015 8:15 AM in response to ToolAZBay

Hmm, if you look at the difference between each pair of numbers, they are all over the map, anywhere from 0 on track 1 to 8.6 on Queen of the Rodeo.


I don't think it matters if SoundCheck is on or off when you add the track. I blv that iTunes analyzes the track anyway and stores the correction. However, it only makes use of it if you are doing playback with SoundCheck on.


Anyway, mystery not solved.... 😕

May 17, 2015 6:19 PM in response to ed2345

Hi !


It seems that Apple has introduced a new "Album Mode" in iTunes (and maybe on new iOS).

See here : http://productionadvice.co.uk/sound-check-album-mode/


But, I did some tests on that and found some strange behaviors though. Even if I play tracks in random on the same album, in some circumtances, the "Volume" value is not honored by Sound Check ??!!


I don't really understand how Apple has implemented and modified the Sound Check feature in iTunes 12 either...

It's still a real mystery for me !


Torp

May 18, 2015 6:01 PM in response to torpidlittle

Interesting news! Although it is still not clear exactly what Apple has done.


That link to Ian Shepherd's article does contain one assumption with which I do not agree. There is no uniform agreement of what "sounds better." The big dynamic variations that sound so dramatic in a concert hall become downright annoying when you listen with earphones in less perfect conditions.

Soundcheck in iTunes 12

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