thoughts on 128 kbps AAC - transparent?

Discussion in 'Digital Audio' started by Megatron, Jun 20, 2007.

  1. Megatron macrumors regular

    Nov 19, 2005
    Hi all - I just did some research reading about all the different encoding formats, and it seemed to me that 128 AAC was the best bet. I read that there were some listening tests with 128 AAC that demonstrated it was fairly transparent to the average listener.

    Apparently the newer mp3 encoders (such as LAME) are pretty good, but I eventually decided to stick with the AAC encoder in itunes just for ease of use and I must say I'm pleased with the results.

    Obviously there is some loss of quality from the CD source, but I tried to listen to both and couldn't tell the difference. I was using a pair of sennheiser headphones to test.

    Audio experts - what are your thoughts? My primary audio outputs will be the mbp itself, headphones (either my sennheiser over ear or some sony in ear ones), and a klipsch 2.1 promedia speaker system. I don't have the money for an expensive soundsystem! :)
  2. netdog macrumors 603


    Feb 6, 2006
    While my entire CD collection is archived in triplicate in ALAC, I use 192 AAC for my iPod and I must say that it is pretty good. 128 definitely shows its own shortcomings quite clearly. Listen to the cymbals or singers as they sing words with an "s" sound in them for obvious flaws in such extreme compression. 128 is definitely not transparent. Then again, I think a 44.1 sample rate is far from transparent and lament that the music industry settled on such a cr@p standard for CDs.
  3. Megatron thread starter macrumors regular

    Nov 19, 2005
    Interesting reading on that thread, the graphs clearly show a difference between the 128 AAC/Mp3 and the original file - but that is to be expected because compressing a song strips away some of the sound spectrum. I guess the question is are those parts the ones that our ears (average person) can hear?

    I tried listening to some songs with "s" and cymbals, and they seemed ok to me.

    I definitely understand that point though - listening to an older mp3, I could hear where a cymbal sounded and the sound got all choppy. I would think though that AAC is newer and each time apple updates itunes/quicktime, they would be making improvements to the algorithm?
  4. zimv20 macrumors 601


    Jul 18, 2002
    frankly, i'm a lot less concerned with what the "average" ear hears, and more concerned w/ what i hear and with how much disk space i'm willing to dedicate.

    the cymbal tails are the tell-tail sign for me. if you're not bothered by what you hear at your chosen bit-rate and algorithm, why do you care what anyone else thinks?
  5. Megatron thread starter macrumors regular

    Nov 19, 2005
    Very good point - I just wanted to make sure I wasn't missing anything because I'd rather record my library (optimally) now while I have some free time, rather than having to re-encode it again later.

    I'm using a 8GB iPod nano, so space is somewhat important. Thanks for the tips.
  6. scottlinux macrumors 6502a


    Sep 21, 2005

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