AAC listening test results

Posted:
in iPod + iTunes + AppleTV edited January 2014
The results of the 128kbps AAC listening test are available:



http://rarewares.hydrogenaudio.org/t...t/results.html



Interesting.
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Comments

  • Reply 1 of 23
    eugeneeugene Posts: 8,254member
    Interesting since Apple is supposedly using a version of Dolby algorithm while the Sorenson MPEG-4 Pro encoder is Fraunhofer based. Haven't the people on Hydrogen Audio been alleging the QuickTime encoder sucks terribly?
  • Reply 2 of 23
    As far as I'm aware the QT encoder performed quite well in the 64kbps AAC test they ran previously (though it was still at version 6.1 when that was run).



    Generally the board focuses on encoder transparency (i.e. inability to tell the difference between encoded and original) rather than low bitrates so AAC in general gets downplayed in favour of MPC and LAME -alt-preset-standard.



    The main problem is that all the other AAC encoder will do VBR and in almost every case Variable Bitrate will beat Average Bitrate encoders.



    I've still not heard a convincing explanation of why Apple is focusing on ABR.
  • Reply 3 of 23
    moogsmoogs Posts: 4,296member
    Not precisely a smooth segway, but I am interested in knowing how many of you have had success in downloading songs from the Music Store, burning them to CD and then being able to play them on the average car stereo. The test being, is the quality of playback decent?



    Can it even be done since most of today's CD players were designed long before AAC? I have about 15 songs I want to buy but I would listen to 90% of them in the car on my way to and from work every day, not my Hi-Fi system. For that nothing I've seen approaches the quality of standard CD AIFF files.... other than HDCD I mean.



    What are your experiences? Would I have to save the files as AIFF before transfering to CD? Quality after such a transfer is made?
  • Reply 4 of 23
    ast3r3xast3r3x Posts: 5,012member
    Quote:

    Originally posted by Moogs

    Not precisely a smooth segway, but I am interested in knowing how many of you have had success in downloading songs from the Music Store, burning them to CD and then being able to play them on the average car stereo. The test being, is the quality of playback decent?



    Can it even be done since most of today's CD players were designed long before AAC? I have about 15 songs I want to buy but I would listen to 90% of them in the car on my way to and from work every day, not my Hi-Fi system. For that nothing I've seen approaches the quality of standard CD AIFF files.... other than HDCD I mean.



    What are your experiences? Would I have to save the files as AIFF before transfering to CD? Quality after such a transfer is made?




    iTunes (if u click burn cd of the songs u downloaded) will convert them to AIFF (or wave or wahtever the format is) when it burns them to the CD so compatibility is not a problem.



    think of AAC (mp4) like this, this is how it was described by somone on the mp4 research team i was watching him on the history channel



    mp4 unlike mp3 which is compressed music, mp4 is really completely different, mp4 is like sending the notes of the music itself not a compressed version of the song, so the comptuer does the work of creating the music



    try AAC...the quality (for 128kbps) is amazing





    sidenote: the guy also said that mp3 was supposed to be 10% of teh original size of the song...and mp4 was supposed to be 10% of that...well i havn't found it to be that but its pretty nice
  • Reply 5 of 23
    baumanbauman Posts: 1,248member
    Quote:

    Originally posted by ast3r3x

    ....

    think of AAC (mp4) like this, this is how it was described by somone on the mp4 research team i was watching him on the history channel



    mp4 unlike mp3 which is compressed music, mp4 is really completely different, mp4 is like sending the notes of the music itself not a compressed version of the song, so the comptuer does the work of creating the music



    try AAC...the quality (for 128kbps) is amazing



    sidenote: the guy also said that mp3 was supposed to be 10% of teh original size of the song...and mp4 was supposed to be 10% of that...well i havn't found it to be that but its pretty nice




    So, AAC can be compared to MIDI?!?



    Seriously, though, what bit rates would you say AAC is comparable to CD quality? I haven't had much of a chance to play around with it, but I kinda doubt that 128kbps really is CD quality. What do you all think?
  • Reply 6 of 23
    moogsmoogs Posts: 4,296member
    So basically I just set up my burn preferences to "Audio CD" and the AIFF thing is done automatically whether the original is MP3 or AAC?
  • Reply 7 of 23
    kickahakickaha Posts: 8,760member
    Quote:

    Originally posted by Moogs

    Not precisely a smooth segway,





    AAAAAAAAAAAAAAAAAAAAAAAAAA!



    My wife predicted this would happen, the day Kamen unveiled his wee beastie...



    The word is segue. SEGUE!



    Segway is a brand name. It's a pun.



    God, I was really hoping she was underestimating people...



    </rant>



    We now return you to some thread about audio...
  • Reply 8 of 23
    Quote:

    Originally posted by Moogs

    So basically I just set up my burn preferences to "Audio CD" and the AIFF thing is done automatically whether the original is MP3 or AAC?



    Yes, just burn a standard audio CD and you'll be cool, it doesn't matter if you bought it through the iTMS or ripped it yourself. The sound quality of the burned CD will be *exactly* the same as the original mp3 or AAC file.



    As to the AAC/MP4 being like MIDI and actually describing the musical makeup of the song, I think there is some confusion here, perhaps with one of the other mpeg technologies (7 or 13 maybe?) as the basic technology behind AAC is the same as mp3. That is, remove large amounts of audio data based on psychoacoustic models that tell you what parts are important to the human ear/mind.



    edit: just tried to Google for mpeg13 and ended up on a really weird porn site ("Erotic Competition Woman-to-Woman!", "The Rules Are Simple! One woman forces the other to orgasm against her will!") and the rest seemed even less useful.



    If anyone else knows what the real name of this MIDI-like project was/is then please let us know.
  • Reply 9 of 23
    moogsmoogs Posts: 4,296member
    Quote:

    Originally posted by Kickaha

    AAAAAAAAAAAAAAAAAAAAAAAAAA!





    Segway is a brand name. It's a pun.



    God, I was really hoping she was underestimating people...



    We now return you to some thread about audio...






    A. I know I was not using the correct spelling. I simply did not know it off the top of my head, and was too lazy to click the link to Dictionary.com to go look it up. Sad for a former Journalism major I can admit, but I know how to write so [relax]. Of course, if you would like a little written joust I can accommodate you, but I don't think that's what you want.



    B. I know Segway is the brand name, and I truly don't care because in five years no one will remember it. Might as well use it while it's fresh in people's minds.... eh?



    C. You'll be thrilled to know my newly downloaded AAC files sound very nice.



  • Reply 10 of 23
    ast3r3xast3r3x Posts: 5,012member
    Quote:

    Originally posted by bauman

    So, AAC can be compared to MIDI?!?



    Seriously, though, what bit rates would you say AAC is comparable to CD quality? I haven't had much of a chance to play around with it, but I kinda doubt that 128kbps really is CD quality. What do you all think?




    haha hey i'm just saying what the guy said and he was suppose dto be an expert...he did tlak about how ti takes away parts of the music the human ear can't hear also



    i would assume the quality would have to be pretty good though...im thinking 320 would be close but not there
  • Reply 11 of 23
    moogsmoogs Posts: 4,296member
    It's not quite CD quality...very good detail in many songs but a little quiet / flat with others I've noticed. We'll see how the CD thing goes tomorrow morning. You know Monday morning audiences...totally brutal.



  • Reply 12 of 23
    jante99jante99 Posts: 539member
    Quote:

    Originally posted by bauman

    So, AAC can be compared to MIDI?!?



    Seriously, though, what bit rates would you say AAC is comparable to CD quality? I haven't had much of a chance to play around with it, but I kinda doubt that 128kbps really is CD quality. What do you all think?




    196 kbs seems to be very close to CD quality. The high quality of speakers you have, the higher bit rated needed for the music to sound like a CD played on the same system.
  • Reply 13 of 23
    moogsmoogs Posts: 4,296member
    Yah, I would say 192 AAC is pretty damn close to CD quality [for the few CD's I've tinkered with, but I've never "burned back to CD" -- only went from CD to AAC for Mac playback. But obviously, you have to have an original CD and rip them at 192 kbps AAC. I did that with one of my U2 CDs and it turned out very well.



    I am still hoping Apple will give user a choice to boost up to at least 160 kbps AAC one of these days.
  • Reply 14 of 23
    ast3r3xast3r3x Posts: 5,012member
    Quote:

    Originally posted by Moogs

    Yah, I would say 192 AAC is pretty damn close to CD quality [for the few CD's I've tinkered with, but I've never "burned back to CD" -- only went from CD to AAC for Mac playback. But obviously, you have to have an original CD and rip them at 192 kbps AAC. I did that with one of my U2 CDs and it turned out very well.



    I am still hoping Apple will give user a choice to boost up to at least 160 kbps AAC one of these days.




    i think that would be very nice...then again they would have to rip all their songs over again...and that would take up even more space...nice for us but hell for them
  • Reply 15 of 23
    moogsmoogs Posts: 4,296member
    Bahh. Just set up an monster X-Serve or two and let em rip (pun intended).



    Anyway, my commute-oriented music experience today was very positive with the CD I made from my iTunes Store AAC files. The only one that was really disappointing was Paul Simon's "Call me Al" (don't ask, goofy song but I like it for some reason). The whole song is really friggin flat / quiet in the rhythm and brass parts. Weak. The odd thing is, the other Paul Simon tunes from other albums are *really* good.



    Must have something to do with the way the original was remastered or something. I wonder if the AAD, ADD, DDD thing has a pronounced impact on the resulting ACC file?
  • Reply 16 of 23
    haraldharald Posts: 2,152member
    Quote:

    Originally posted by Moogs

    Must have something to do with the way the original was remastered or something. I wonder if the AAD, ADD, DDD thing has a pronounced impact on the resulting ACC file?



    What will have an effect is the TYPE of D at the end of your quartet of letters. Old recordings that were turned into D used shitty AD converters that subtly knackered the timing of the song (AKA the vibe) ... there is a major difference between two 44.1K 16bit recordings at times ...



    There will be those who will say you can't hear the difference. Dey be wrong.
  • Reply 17 of 23
    shetlineshetline Posts: 4,695member
    Quote:

    Originally posted by Moogs

    Anyway, my commute-oriented music experience today was very positive with the CD I made from my iTunes Store AAC files. The only one that was really disappointing was Paul Simon's "Call me Al" (don't ask, goofy song but I like it for some reason). The whole song is really friggin flat / quiet in the rhythm and brass parts. Weak. The odd thing is, the other Paul Simon tunes from other albums are *really* good.



    I've got this same song on my iPod (the whole album in fact - "Graceland" is a classic!), ripped from my own CD at 192K, and it sounds great. It's hard to know how much difference the iTMS rate of only 128K would make, but the effects you're describing sound more like bad equalization somewhere along the line than audio compression artifacts.



    Must have something to do with the way the original was remastered or something. I wonder if the AAD, ADD, DDD thing has a pronounced impact on the resulting [AAC] file?



    I suppose there could be some effects from analog steps in the recording chain, but I'm not sure what the magnitude would be. Certainly broadband noise is tough on lossy audio encoders, and I can see the wow and flutter of analog tape complicating matters as well.
  • Reply 18 of 23
    moogsmoogs Posts: 4,296member
    Anyone know if I have any recourse to try and "download again" and see if the resultant file sounds better? As I listen to it more it really kind of sucks. It's like it was recorded / ripped at a completely different volume / tonal settings (maybe the EQ thing like Shetline suggests) than the other stuff. One of my Eagles songs was a little muffled too (One of These Nights).



    I wonder if they have different copies (i.e. somehow not identical) of the same song on different servers, and what you get just comes by happenstance (obviously). I dunno...
  • Reply 19 of 23
    anamacanamac Posts: 80member
    The word is segue. SEGUE!





    But isn't "not precisely a smooth Segway" what Dubya said a few weeks ago when he fell off?
  • Reply 20 of 23
    moogsmoogs Posts: 4,296member
    *Slaps Forehead*



    Ok, now...follow along closely. I want you to go back and read the little exchange that was had earlier on this critical matter. Was there anything there that lead you to believe it was a moral imperative to once again point out the proper spelling and usage of segue? Huh? Are you trying to kill this fine thread...is that what you're up to?



    Watch yourself pal or I'll beat you over the head with a 20MB mono MP3.





    Moving right along, I think Shetline hit the nail on the head: Apple biffed on the some of the EQ when ripping their music store files. I guess when you have that many files to work with it is inevitable that some will get messed up. When I play those particular songs, I have to turn the volume up close to 50% on both my computer and car stereo in order to hear the songs at the standard volume the others play at. Wierd.
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