High Five Mastering

Audio Mastering Studio

Mastered for iTunes

If you have read the Online mastering & lossless wav format tab you now know that digital downloads are largely outselling physical copies mainly due to singles. And when we talk about digital sales we have to mention Apple’s iTunes store. It is the biggest music digital distributor with over 25billion songs sold and with stores in over 119 countries.

Before launching the iTunes store Apple favoured to use the AAC (Advanced Audio Coding) file format to the deficient and then already somewhat “obsolete” mp3. Apple have seen the potential of AAC as it was able to achieve much better sound quality at the same bitrate compared to mp3 (and it also required no license!). You may find this surprising but AAC is the default audio format not only for all Apple products (over 2 billion iOS devices sold!) but also for Android (2 billion devices sold!), Blackberry, Nokia, Sony Erickson, Playstation or for platforms such as YouTube and others. It’s a hefty chunk of pie!

Still the lossy formats were heavily criticised by many leading artists and public, which forced Apple to further develop the algorithms and this is how “Mastered for iTunes” was born.

Without going into too much details about how the codec works here is a brief explanation (in leyman’s terms of course!). The codec is based on a psychoacoustic model, which is based on human hearing. Based on the output settings the codec is eliminating perceptually insignificant events rendering the audio file smaller in size.

The original AACs were converted from Audio CD quality files, so 44.1kHz/16bit. Problem with this was that the codec had to take out data from already relatively small file. But as of 28th of February 2012 Apple made public an encoder that could work with 96kHz/24bits. Allowing a lot more headroom for the encoder to work with, which resulted in far superior sound quality.

Yes, I know what you might be thinking right now: “I will get the masters in the highest possible quality and will convert them myself.” But it’s not as easy as pressing that “create to AAC version” button in your iTunes! First thing to have in mind is that the conversion process will eliminate certain frequencies from the audio – and you never know which ones! Second is that your lossless master will handle higher amplitudes better which might often reach as high as 0dBFS. When such loud masters are converted to AAC+ it will cause the file to clip and digital distortion will be introduced! And bear in mind Apple’s Mastered for iTunes terms: “[…] tracks which have audible clipping will not be badged or marketed as Mastered for iTunes.” Quote.

So when you order the Mastered for iTunes service, I will audition your files using the iTunes Plus AAC+ algorithm prior to converting them, which will enable me to:

1. Make spectral adjustments for this specific format (44.1/128kbps (for mono) or 256kbps (for stereo) in Variable Bit Rate) making sure your AAC+ sounds as close to the lossless original as possible.

2. Prevent clipping and minimize the distortion for the best audio quality.

3. I will convert your files ensuring they are 100% AAC+ compliant and to the highest standard so that you can submit them to the iTunes store as “Mastered for iTunes".