Audio format war! AIFF vs. MP3 vs. AAC and the winner is...

Recently, I posted a response to T-Bone Burnett’s notions that up and coming artists should “stay completely away from the Internet” and that MP3s are an “unlistenable” format. I disagreed with T-Bone on both counts. I was annoyingly sure of myself until my friend Cory left a comment.

Cory pointed out that T-Bone probably didn’t mean that new artists should never go online, rather that they should focus on their playing skills instead of their coding chops and number of Facebook friends. Fair point, and most likely true.

Cory went on to agree with T-Bone that MP3s suck, and considering Cory’s music and tech chops (he was one of the original staffers at Digidesign and now runs a major group at Apple), my certainty that MP3s could sound nearly indistinguishable from full, uncompressed CD files wavered. Then T-Bone Burnett himself commented, taking me to task for being a jerk (he was right) and hammering on MP3s a bit more. So I set up a listening test for myself.


A quick refresher on audio file formats. Today there are three primary contenders in widely available music:

AIFF This is the standard audio file format on CDs. AIFF stands for Audio Interchange File Format and it is uncompressed, so file sizes are big (typically over 30 MB).

MP3 MP3 stands for MPEG-1 or MPEG-2 Audio Layer 3 and is the leading standard for “lossy” audio formats, meaning the audio is compressed to reduce file size. MP3 files are typically about 11 times smaller than AIFF, yet supposedly achieve a faithful reproduction to most ears.

AAC Advanced Audio Coding (AAC) was developed to outperform the MP3 format and is the format used be Apple iTunes.

AIFF is always the same quality level, but MP3 and AAC can change based on their bit rates. Typically, Amazon and iTunes use a bit rate of 256 kbps for downloads, whereas most streaming files are served up using 128 kbps (to save on bandwidth).

To compare the sound quality of these dominant formats, I imported “No Reply” from“The Beatles For Sale” (remastered), “Four Sticks” from “Led Zeppelin IV” (remastered) and “Up in Indiana from Lyle Lovett’s “It’s Not Big It’s Large”. I chose “No Reply” to get good old tube sound across the board, with plenty of dynamics; I chose “Four Sticks” for its complexity and because Jimmy Page was such an incredible producer; and I chose “Up In Indiana” because Lyle Lovett always hires peerless musicians and seeks to create exquisite sound quality, the latter of which should be best exemplified by this recording as it is one of his most recent.


I played the songs back on my Mac Pro and listened through my speakers, which are Audioengine 5s, then through my headphones, a pair of Grado SR80s.


A full-on, no-doubt-about-it, definitive... draw.


How can this be? How can an audio file that’s an eleventh the size of the original equal it? I don’t know, but it can and it does. Truly, I listened the reverb decay on Lennon’s voice in the beginning of “No Reply”, the complex musical interplay in the middle of “Four Sticks”, and the quivering cool of Lyle’s voice at the beginning of “Up In Indiana” and throughout I used iTunes to switch back and forth between file formats. And here’s the real shocker: the lowest quality MP3 and AAC files sounded identical to the AIFFs. I’m sure there’s a difference, but it is damn subtle.

Perhaps its my gear. Maybe if I had listened to these files on my $700 Denon CD player running through my Nakamichi amp and out my handmade, boutique speakers built in Oregon out of solid steal, I could tell the difference. Or maybe if I had imported the AIFF files into Pro Tools and used the DACs (digital to analog converters) in my MBox 2 Pro I would have heard a difference. But should the difference really require such high-end gear? I don’t think so.

Honestly, I’m depressed by this test. In fact, I’m convinced that something must be wrong. Maybe iTunes is defaulting to the AIFF file always? No, I removed them and listened again, same old story. Maybe my hearing sucks after too much time in front of loud guitar amps? I don’t think so, it’s been tested and it’s fine. Maybe my damaged brain hears differently now? Possibly, but I doubt it.

Despite the overwhelming evidence that compressed audio formats sound as good as CDs, I will still buy CDs. I can’t help it, I love great sound quality, and I need to know that I have the best source files around. What’s more, I plan to buy a new SACD player (mine is on the fritz) and I await Blu-Ray audio eagerly. I will go to my grave shunning MP3s, but I have to admit, they sure sound good.