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Has anyone did a blind test on iTunes AAC vs CD/Lo

I cannot tell a difference on any system I listen to between an iTunes download (256 aac) vs a CD track or lossless 16/44. Now my living room system is low to mid fi (Pioneer Elite). My small studio has Yamaha HS series monitors which are pretty revealing IMHO. I've also listened thru my Grados (Pioneer Elite headphone jack). I can hear artifacts in the MP3's I've listened to (slight swishy XM radio sound). But the 256 AAC sounds just as good. 98% of my music purchases are CD's. I like physical media...but the iTunes downloads sound identical. Please chime in
aberyclark
aberyclark OP
1,410 posts
 
Good info. I only tested with iTunes downloads and cd. I never tried comparing a burned CD-r. Eventualli, I hope, Apple switches iTunes to apple lossless. I highly doubt it with the iCloud service coming up. I believe all iTunes material is stored on Apple's servers at full resolution. The encoding and downsampling occurs during the download process (thats what I've heard)
shadorne's avatar
shadorne
7,490 posts
 
I'm curious to see if anyone on here, with a really high end system, can tell the difference.

You don't need a really high end system (although it helps). You simply need to know what artifacts to listen for. I can hear audio compression on a boombox or car system.
realremo
460 posts
 
Hmm, did not know the iTunes music gets compressed on download, that's interesting. I still think a 256 AAC purchased from iTunes sounds better than one I create myself, there's some tech there that I don't have access to. Of course I haven't tested this with the same track, its just a general statement right now, my impression. I might test this in the future, but for now, I prefer to buy CDs. I like having the media, and I have shelving to fill!
aberyclark OP
1,410 posts
 
I'm the same way. I prefer physical media. I have pretty sensitive ears and can spot major compression artifacts quickly. But, i'm at a loss with an iTunes downloaded track. At least with the system I have now. I wonder if the above poster actually listened to an ACTUAL iTunes 256 AAC download. If he is hearing artifacts on those files he has some golden ears. I can id pre echo, mild wobbling or distortion with lower resolution tracks as with MP3's at 320. I know the artifacts exist on the AAC's, I just do not have the ability to hear them (yet).
grege
47 posts
 
Great topic!
I have been burning at AAC 256, 320, and lossless. I have Martin Logans which are pretty revealing. In blind testing I can hear no differences between CD and lossless, possibly minute differences between CD and 320 AAC but it is extremely close. Slight changes start to appear at 256 and below in terms of high end and low end rolloff, loss of room size, and lack of air. I have settled on AAC 320 for my ipod and using the Pure i-20 dock, have replaced my CD player as my source.

The guys over at hydrogenaudio strongly disagree with this and state that in double blind testing with the latest encoders, AAC 128 and higher is 100% transparent.
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