There can be only one iTunes track

Bobby Owsinski got some Mastered for iTunes questions answered directly from Apple representatives.

“Mastered for iTunes” is only an indication that a hi-res master was supplied; it’s not a separate product. There will always be only one version of the song on iTunes at the same price as before. “Mastered for iTunes” doesn’t mean you get to charge more, or that iTunes charges you more. Everything is like it was before, you just supply a hi-res master so it sounds better.

Which would indicate that anybody using iTunes Match is getting the Mastered For iTunes version of tracks. Good news if you thought you’d have to repurchase all those Pink Floyd albums for the Mastered for iTunes magic.

Also on sound quality:

Speaking of the sound quality, iTunes is now using a completely new AAC encoder with a brand new algorithm and the sound quality it produces is stunning. It provides an excellent encode if you use a few common sense guidelines (more on this in a bit), and if you do, the result is almost impossible to hear (at least on the music we listened to). I mean, there we were, mastering engineers Eddy Schreyer, Gene Grimaldi plus myself, listening in this fantastic listening environment, and we literally couldn’t tell between the source and the encode most of the time.

Mastering engineers, people who do this professionally for a living, have trouble identifying a 24/96 studio master from a 16/44 AAC file. Meanwhile, read any of the comments on these types of articles and you’ll find comments from people who think they have golden ears and demand FLAC, high-resolution downloads.

Why? Because higher numbers are better. It’s science!

They did the math, but they didn’t use their ears.

“Ace Engineers Share Tips for iTunes Mastering”

More discussion on the Red Hot Chili Peppers iTunes-specific master.

The claim, here:

Apple’s 256 kbps AAC files are supposed to sound pretty close to CD-quality and they routinely fool listeners in double-blind listening tests. But when record-producer/living-legend Rick Rubin heard the iTunes version of his new Red Hot Chilli Pepper production I’m With You, he was reportedly appalled by how its sound changed during the conversion process.

But then here:

The two had to run the masters through a specialized replica of the iTunes Store proprietary AAC encoder using command-line code, because the store’s codec is different than the consumer-grade iTunes converter.

This is the first I’ve ever heard that the iTunes Store AAC encoder is different, and higher quality, than what every iTunes software user already gets.

The article also contests Ian Shepard’s null test.

All of this goes without even mentioning that null tests are only useful in establishing whether or not any difference exists between two files. Null tests however, have not been established as a reliable measurement of how audible those differences are. A blind ABX test would be necessary to give some indication as to which file real-world listeners think is closer to the original.

Also check out Bob Ludwig’s thoughts on Mastering for iTunes (they’re favorable and he explains why).

Ian Shepard Calls BS

Mastering engineer Ian Shepard does a null test1 on three versions I’m With You by the Red Hot Chili Peppers. This was the album that had a specific master for iTunes.

Go to the link for the Youtube video. Since it’s youtube you won’t really hear the exact audio, but you’ll get the point.

His findings have more to do with that iTunes Master for the RHCP record than it does with Apple’s Guidelines for iTunes Mastering. iTunes Mastering is not aiming to sound like a CD. It’s aiming to sound like the original source material. But in the RHCP example, they attempted to compensate for the encoding.


  1. A Null Test is when you take two waveforms, invert one, and play them at the same time. If they’re exactly the same you should hear silence. If not, you hear the leftovers. I’m probably butchering this explanation. 

Apple’s Mastered For iTunes Pages

Finally some explanation direct from the source:

An ideal master will have 24-bit 96kHz resolution. These files contain more detail from which our encoders can create more accurate encodes. However, any resolution above 16-bit 44.1kHz, including sample rates of 48kHz, 88.2kHz, 96kHz, and 192kHz, will benefit from our encoding process.

Now this is a little different that just boosting EQs for white earbuds. They are starting with the high resolution audio and encoding that down, rather than going through all that for a CD and then encoding the CD and sending that to Apple. The iTunes Producer software sends your music to Apple to sell in iTunes used to just encode your CD as Apple Lossless and upload it to Apple. Looks like this is changing.

I still get wary when an audio engineer says they’d still pick the CD as the highest quality commercial release. And how, if iTunes is still publishing these songs as 44/16 AAC files, is this different than doing this same downsample and dithering process for a 44/16 CD?1

This bit is interesting. Apple is trying to serve as the archive of nearly all digital masters.

…though it may not be apparent because there may not always be a physical, tangible master created in LP or CD format, the iTunes catalog forms an important part of the world’s historical and cultural record. These masters matter—especially given the move into the cloud on post-PC devices.


  1. Looks like there may be at least a couple of reasons, like built-in soundcheck profiles and 32-bit floating-point files used during sample rate conversion. 

“Mastered For iTunes” on iTunes

Mastered for iTunes means these albums have been specially tuned for higher fidelity sound on your computer, stereo, and all Apple devices. Browse a range of music across all genres below, and keep checking back as we add more music that is mastered specifically for iTunes.

This page on the iTunes Store displays albums marketed as “Mastered for iTunes” including:

  • Coldplay – Mylo Xyloto
  • Lana Del Rey – Born To Die
  • Paul McCartney – Kisses on the Bottom

If you’re suspicious of Mastered for iTunes you might think that that’s ok, because they’re all pop releases, but oh, golden ear music snob, you’ll also find classic and classical albums like

  • Philip Glass’s Symphony No. 9
  • Frampton Comes Alive
  • Holst: The Planets
  • John Coltrane – A Love Supreme
  • Everything by Pink Floyd

I think that Mastered for iTunes is a marketing ploy that could degrade mastering processes, discourage better encoding, and ultimately won’t work to win over audiophiles. But they don’t need to. There are people who rip their CDs at 48khz.

“Nearly unlistenable”

An Amazon reviewer on Lindsey Buckingham’s new album:

As usual, this is a brilliant album, full of some of Lindsey’s best and weirdest material. Also as usual, the album is mastered LOUD so that much of the nuance of the sound is missing. I wish that Lindsey hadn’t succumbed to the record company mantra of “MAKE IT LOUD” and that he had allowed the music to shine through. Four stars for the album, minus three for the fact that it’s nearly unlistenable.

Other commenters disagree, saying it sounds fine.

I wonder how much of that has to do with the Amazon MP3 Exclusive work. Did this and the other digital music formats get a separate master that sounds good over white earbuds?

This is now what I think when I see an album with “Amazon MP3 Exclusive” in its title.

Mastering for iTunes

Digital Music News interviewed Vlado Meller, the mastering engineer on the new Red Hot Chili Peppers album, which has three masters: one for CD, one for vinyl, and one for iTunes.

Digital Music News: What specific considerations play into the AAC mastering process? Can you really make a version that brings white earbuds to life, or is that not the point?

Meller: Yes, with an iTunes optimized master, the listener will be able to enjoy more clarity and an overall better sound quality than is otherwise currently available.

I hope this doesn’t become a standard practice, because it seems like a load of bull. Meller even states that he’d pick the CD version as the “highest quality” for commercial release.

Back in 2009 I wrote:

…mixing for a certain encoder means giving those encoders a pass. Better to let the flaws of the encoder shine through so that the market can choose to not use that encoder and move on to something better.

Since the launch of iTunes Plus we’ve learned that most people still can’t hear the difference between 256kbps AAC and 128kbps AAC. And people already had a hard time hearing the difference between a 128kbps file and the original CD.

If the CD is the true master then why create an iTunes specific master? Hype is my guess. Maybe it will persuade people to buy two copies of the album—a CD for the car and the download for the office.

When you hear people talking about mastering for iTunes are they really talking about mastering for AAC or are they’re talking about mastering for white earbuds?

Link: Metallica’s New Album Sounds Better in Guitar Hero than CD

I haven’t heard it yet, but Death Magnetic has apparently been squashed flat – no dynamics at all, unless you’re listening to the Guitar Hero version:

Via 1up:

Metallica’s latest album, Death Magnetic, was finally released to the world on September 10 — including to Guitar Hero III players, as the album was also released in-full as downloadable content. But according to keen-eared fans who’ve heard both versions, it turns out the sound quality in the Guitar Hero DLC is actually better than the quality of the retail CD. And according to Ian Shepherd, a mastering engineer and DVD author at SRT, they aren’t just hearing things.

Check out the difference in the waveforms between the Guitar Hero version (top) and the CD (bottom) that SRT Mastering Engineer Ian Shepherd notes:

metalliac_cdvsgh.png