iVolume effectively repairs the built-in “Sound Check” function of iTunes. Information about the loudness is stored by iTunes in a tag named iTunNORM inside your songs. This information is used for playing a song a bit louder or softer at playback time whenever Sound Check is turned on. iTunes' loudness analysis is very fast but unfortunately not very accurate so that Sound Check is not satisfying out-of-the-box. That's were iVolume comes into the game: iVolume re-analyzes every song with a professional algorithm that's oriented on the acoustic perception of the human ear and iVolume then permanently replaces the information in the iTunNORM tag of your songs with perfect values.
No. iVolume does not re-encode your songs. It just replaces the information in the iTunNORM tag with perfect values. This information is used at playback-time to play a song softer or louder whenever Sound Check is turned on.
No, you just let iVolume run once (every time you've added new songs) over your library. Then you play your songs as usual with iTunes, your iPod, iPhone, iPad, or Apple TV. You just have to make sure to have Sound Check turned on in iTunes or on your playback device so that the adjustments made by iVolume take effect.
iVolume supports all formats that permit embedding the iTunNORM tag; currently that is MP3, AAC (.m4a, .m4b), AIFF and Apple Lossless. Unfortunately Video files and WAV files do not support the iTunNORM tag, so they can't be adjusted by iVolume.
Yes, songs purchased in the current “iTunes Plus” format (.m4a) are supported. Older iTunes purchases may not be supported, because songs purchased before mid 2009 usually were copy-protected (.m4p) and that renders third party applications like iVolume impossible to decode such a song. Please see the iTunes Store for details about upgrading your music to the iTunes Plus format if you're affected by this.
Unfortunately that depends. There seem to be at least two different ways to get audio out of the Dock Connector. Most probably that is analog and digital. In some cases Sound Check works just fine, but in other cases the volume adjustments are simply ignored. Hopefully Apple fixes this issue at some time. The best option is to use the headphone jack whenever possible.
Just turn off Sound Check and all modifications made by iVolume will be ignored and your songs all play at their original volume level.
Yes. You have to use iTunes to burn the Audio-CD. In the burning dialog of iTunes there is a checkbox “Use Sound Check”. Turn that on to burn volume adjusted Audio-CDs.
It displays the current speed factor of the song analysis compared to the real duration of the songs. E.g. if it displays a factor of 60, a 5 minute song is analyzed in just 5 seconds. While analyzing it additionally displays the number of available processor cores.
Please don't confuse the “Volume Adjustment” sliders with “Sound Check”. iTunes offers two ways to adjust the volume of songs. The manual “Volume Adjustment” slider is in the “Options” tab of the song information dialog. But iVolume modifies the “Sound Check” information. This value can be seen in the “Summary” tab of the song information dialog; it's labeled “Volume”. For best results, the manual “Volume Adjustment” sliders have to be set to “None” so that they do not interfere with “Sound Check”. But iVolume can check this for you automatically.
If you have a Mac running Mac OS X 10.4 or 10.5 or a Mac with PPC processor, please download iVolume Version 3.6 here.
