Apple silently introduces album normalization in iOS 8.4.1

I disscovered this accidentally when I tried Sound Check after a while. Now normalization is not between tracks only, now every album sounds with aproximately same loudness but levels inside an album are preserved (it doesn't messes gapless albums like before). I sent Apple Suport an email asking them if they can implement this, so I'm really happy believing they done it for me

 

This is a characteristic of iOS, or iTunes?

 

It was in iTunes since iTunes 12, and now it is on iOS also

 

Good job apple, welcome to 2005!

 

Yeah, I've had this on Foobar for years.

 

I don't get it. So each song in an album is aprox. the same volume as opposed to leveling all songs in ones library?

 

I could be wrong, but I think it's just album gain as opposed to track gain.

 

Ok, that makes sense. When would that you need that feature? If the tracks within an album all came from different sources-cd, download, vinyl rip, etc?

 

Anyone who has an all digital library loves this feature. It saves you from reaching for the volume knob when you go from something like Every Breath You Take (which is mastered well but quiet) to American Idiot (which is mastered extremely loud). Even if you don't play your songs on random, it's a nice feature when you switch between albums for the same reason. I like having all my albums at a "peak" loudness. You still have the dynamic range of the album, but it is increased/decreased to match the rest of your library.

 

Not that it matters much (to me) on a mobile device, but does this normalization degrade the signal any, as some argue happens in OS X iTunes? Is there a way to defeat it in iOS?

 

I'm not an audiophile techie by any means, but I think it just lowers the volume digitally. Yes, it can degrade the signal if you make things too loud and bring clipping into the equation, but usually you lower the volume (the default volume is 89dB, I believe), not raise it, so that shouldn't really happen.

Mobile devices are starting to get this feature. I use Muzecast, and it reads the RG values from my computer while playing back the song, and it's pretty nice when you have a mix going on.

 

It doesn't degrade the sound at all, and it doesn't degrade it in iTunes either. What it does it just tell the playback software to play a song quieter (or louder) than it would normally do. It's exactly the same as reaching for the volume control in your software, your computer or your phone. The files are not altered at all. If some think that it degrades the sound in iTunes, then they've been misinformed — or do they think that playing a file on a computer at any other volume than maximum volume degrades the sound?

On iOS it's to be found in Preferences, under Music. Usually it's turned off by default, but it might be turned on on newer devices.

 

Clipping is not possible at all in this case — like you said, just the digital volume control is being altered. Even in a highly unlikely theoretical case in which a file has been erroneously pushed up by "Sound Check" to, say, 12 db louder, clipping cannot occur. What happens is the following: as you raise the volume from 0 up, the file will become loud quite fast and in fewer steps, after which it reaches a plateau – you continue to raise your device's volume, but nothing happens anymore, because the maximum volume of the device has been already reached.

Clipping can only be introduced in iTunes by means of EQ-ing.

 

I guess I'm not understanding something then, because I would have thought if you raised the volume of something 6dB, and some of the peaks of the track were only 3dB away from max volume, you would clip the signal, because you can only raise it 3dB but you just raised it 6dB, so those peaks have nowhere to go. But I may be confusing myself.

 

I feel that digital volume control does degrade the sound but perhaps I've been misinformed. Isn't it no longer bit-perfect playback of the original data if it is being altered by DSP in real time?

 

No, you don't raise the volume of the actual file, only the playback volume on your device is being raised. Like I said, the peaks on the file and the waveform are left unaltered. It's like an invisible hand raising and lowering the volume on your device before every track is being played, so that you can the same perceived loudness between different albums.

 

You could be right — but do everyone here just listen to their music on maximum volume because they are afraid that digital volume control lessens the sound quality??

 

I've tried it out for a brief time in the latest iTunes version after reading on the internet that album normalisation was finally being implemented. Actually there is a video on the net that claims that album normalisation is only working when you are listening in "album mode", but if you shuffle tracks of an album or your entire library, track-by-track normalisation kicks in again.

However, none of that really worked out in my case — I've found that tracks still varied a lot in terms of volume after turning on Sound Check in iTunes 12. You can actually check the determined playback volume alterations in the Info pane for each track. They were all over the place and they sounded like that. So I had to turn it back off again.

 

Don't worry. The Apple fanboys will be trumpeting this as another stroke of Apple brilliance...Just like Apple streaming, Siri, and so many other things that Apple developed years after they existed...

 

I can't imagine what this means for classical music, with its wide dynamic swings. Of course, Apple doesn't give much of a rat's about classical!
-Bob

 

Windows media has normalization for recording mp3s to cd. But I always leave that box unchecked in fear that this could mess with the dynamics on some songs. Am I just being paranoid ?

 

Yes, that will mess it up Although I think it's safe to believe that that kind of normalisation has a sort of clipping prevention. Probably.

 

No, you're not being paranoid. I would avoid that as well. Avoid anything that involves reprocessing the ripped data.

Foobar (and other applications) uses ReplayGain, an open-source standard that calculates a track's true RMS audio value, and stores the information in the file's metadata (mp3, m4a, flac etc.). Further, if you rip an entire album, ReplayGain will calculate a 'median' RMS level for all tracks - so you get a smooth, accurate representation of the album's dynamics, start to finish. There is no processing - this data just tells your music player where the playback volume level should be set.

ReplayGain is great mostly because it does nothing to alter the file, aside from providing the level information in the metadata.

 

Probably not everyone, but I do. Not really max-volume, I just disable all software related volume control so there is no max-level to speak of I typically listen to full albums so it is not a nuisance to me to get up and adjust the volume once. I can see how it can be if one were shuffling though, and (if they are using a vintage receiver like myself) do not have a remote.

 

If this works as I suspect it does, it does not alter the ripped data in the least. Bit-perfect rips are still bit- perfect. All it does is tell the player to raise the volume to a consistent level on a track-by-track or album- by-album basis. Dynamics are not affected at all. If you never listen on shuffle, and never play one album after another, you may not need this at all if you're willing to manually adjust the volume for each album or track. I use iVolume for the same effect and I wouldn't use iTunes without it.