Remastering iTunes Library

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mustbjones
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Joined: Wed Nov 22, 2006 8:35 pm

Remastering iTunes Library

Post by mustbjones »

Sound Check never seems to work correctly for me. If I can get the sound balanced say for a CD, it is all wrong for my iPod. Is there some way I can "re-master" all my iTunes songs (those that are not protected) to the same audio level? Thanks.

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Lou Kash
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Post by Lou Kash »

Amadeus is probably the wrong tool for this job, because it will alter the audio destructively and (unless you're using lossless audio formats in iTunes) lossy.
What you need is a tool that will change the gain value of a track losslessly - which is what Sound Check actually does.
The only tool I know which allows lossless editing (incl. gain adjustment) of AAC files is Fission: http://www.rogueamoeba.com/fission

mustbjones
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Post by mustbjones »

Thanks. Any suggestions on how exactly I would do this?

MartinC
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Joined: Thu Oct 15, 2009 3:01 pm

Post by MartinC »

You can use iVolume for that job:
http://www.mani.de/ivolume/index.html

It works on your current iTunes library and just sets the "Sound Check" value to something better, using the so called "replay gain" algorithm.

It works like a charm. You can also modify the behaviour, for example you set it up to apply the same value to all tracks of an album - this way live albums will no longer be spoiled with volume jumps.

mustbjones
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Joined: Wed Nov 22, 2006 8:35 pm

Post by mustbjones »

Does it permanently modify the iTunes file? Does it work for iPods and CDs? I remember one other utility a while ago that would only work when playing in iTunes itself. It "remastered" on-the-fly.

When I went to check out the price, I was forwarded to the Kagi website. My credit card company has a real hard time "working" with kagi. Might be a deal braker.

Thanks for responding.

MartinC
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Joined: Thu Oct 15, 2009 3:01 pm

Post by MartinC »

mustbjones wrote:Does it permanently modify the iTunes file?
Yes and No... it does not modify the sound data, but it re-writes the "Sound Check" tag value.
Or - to put it more simple: It does *exactly* what the iTunes Sound Check feature does, but it simply calculates a much more usable value.
mustbjones wrote:Does it work for iPods and CDs?
Yes and Yes. You only need to turn on the "adjust volume" checkbox in iTunes and/or on the iPod. If you burn a CD with iTunes, you will get a checkbox asking if it should apply the adjustment.
mustbjones wrote:When I went to check out the price, I was forwarded to the Kagi website. My credit card company has a real hard time "working" with kagi. Might be a deal braker.
It works forever in "trial" mode, it just frequently pops up a "reminder" box. So you can easily try it out - it will work properly (and permanently!) write out the tags, even if you consider not to buy it. Purchase price is 24 Euros (probably some $30 ?)

MartinC
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Joined: Thu Oct 15, 2009 3:01 pm

Post by MartinC »

MartinC wrote:
mustbjones wrote:Does it permanently modify the iTunes file?
Yes and No... it does not modify the sound data, but it re-writes the "Sound Check" tag value.
Or - to put it more simple: It does *exactly* what the iTunes Sound Check feature does, but it simply calculates a much more usable value.
mustbjones wrote:Does it work for iPods and CDs?
Yes and Yes. You only need to turn on the Sound Check (= "adjust volume") checkbox in iTunes and/or on the iPod. If you burn a CD with iTunes, you will get a checkbox asking if it should apply the adjustment.
mustbjones wrote:When I went to check out the price, I was forwarded to the Kagi website. My credit card company has a real hard time "working" with kagi. Might be a deal braker.
It works forever in "trial" mode, it just frequently pops up a "reminder" box. So you can easily try it out - it will work properly (and permanently!) write out the tags, even if you consider not to buy it. Purchase price is 24 Euros (probably some $30 ?)

mustbjones
Posts: 35
Joined: Wed Nov 22, 2006 8:35 pm

Post by mustbjones »

Yes, this looks like what I want. But going over the FAQs and Help I didn't see anything about reversing the process - for whatever reason.

MartinC
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Post by MartinC »

mustbjones wrote:Yes, this looks like what I want. But going over the FAQs and Help I didn't see anything about reversing the process - for whatever reason.
Well... as a matter of fact you can't "reverse" it indeed, but this is not really a disadvantage.

You need to understand what "Sound Check" actually does and what iVolume changes.

Whenever you add a new song to iTunes, then iTunes tries to find out "how loud it is" and stores a value in a tag. This value is something like "-2.3 dB" which means "this song should be played with its volume reduced by 2.3 dB". If you turn on the "Sound Check" checkbox, then it will do so, if you turn it off then the song is played in its original form. The iPod does the same (it has its own "adjust volume" setting that you must turn on/off independently of the iTunes setting - if it's turned on, it will apply the "Sound Check" value). So far so good.

However, iTunes is not very clever. The algorithm to find out "how loud it is" is very primitive and it also only checks few fragments of the song. As a result, the value is badly calculated and so it hardly works.

One way to fix this is the "track volume" ruler that you can set within iTunes. I guess many people will confuse this with the "Sound Check" value, but it actually is *another* value. And - sadly - the iPod tends to ignore this value entirely, because it only really works in iTunes...

Entry iVolume...

All that iVolume really does is to re-calculate the "Sound Check" value and replaces the bad value in the track tag. Different to iTunes, it uses a *good* algorithm (called "replay gain") and it also processes the entire song. As a result, the new value will be correct for the vast majority of tracks.

You must keep in mind that this really is the *only* bit that gets changed in your songs - it does *not* modify the sound data, it only replaces the badly calculated "Sound Check" value with a good one. Indeed it doesn't offer to restore the original (rubbish) value at a later time (and maybe it should do so for the sake of peace of mind :-) but you will hardly ever want/need this...

Another important piece of info: This "Sound Check" value is *not* editable or changeable within iTunes! It only gets calculated once on import and then it sticks forever (unless you use a tool).

But iVolume allows to set/edit/change it - it normally just calculates a good value automatically, but you might as well set it manually. So, in the rare case that you don't like the automatic iVolume value for a single song, you can just adjust it yourself - and different to the manual "Track Volume" in iTunes this values even gets processed by your iPod.

Therefore you should set all manual corrections to "0" (iVolume offers to do that for you, because this value interferes with Sound Check and makes it useless on the iPod) and then make all further corrections in iVolume.
Turn on "Sound Check" in iTunes for adjusted playback and turn on the same option on your iPod - that should solve it once and forever...

(PS: As a matter of fact, one of the things that I regret is just the fact that the iVolume corrections cannot be applied outside of iPod playback, iTunes playback and iTunes CD burning... if you want to use Toast to burn an audio CD from your iTunes tracks and want to apply the iVolume/SoundCheck corrections then it really is a lot of trouble. I just started another [REQ] thread with two feature suggestions in order to improve this - that's why/how I came here and found your thread... :-)

mustbjones
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Joined: Wed Nov 22, 2006 8:35 pm

Post by mustbjones »

Wow MartinC you really know this product!! Does iVolume have a forum? I have a question or two, or three, about combining albums, doing all track individually or treating my library as one BIG library.

MartinC
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Joined: Thu Oct 15, 2009 3:01 pm

Post by MartinC »

mustbjones wrote:Wow MartinC you really know this product!! Does iVolume have a forum?
I don't think there's a forum, but it's not difficult to use. Just play around with it, and you'll find out - it is easy (you can create groups on the left, apply different settings and then just drag your files into it). You can't do any damage, if you get unwanted values then just change your settings and do it again.

I heard about iVolume on other local forums and was sceptical about the praise... because I know that "loudness" and the human ear is a lot of Voodoo. However, one day I gave it a try and it just *did* work...

I'm not connected with its developer in any way, I just bought it and now I'm very happy with its quality... :wink:

Technical details about the "Replay Gain" algorithm can be found here:
http://en.wikipedia.org/wiki/Replay_Gain

iVolume does nothing but using this algorithm and replacing iTunes' value with it.

mustbjones
Posts: 35
Joined: Wed Nov 22, 2006 8:35 pm

Post by mustbjones »

Incredible product. How do they get the ear buds to show outside the main window?

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