What's best: 320 kbps mp3 or 256 kbps AAC from the iTunes store?

Discussion in 'iPod' started by Aragornii, Jan 7, 2012.

  1. macrumors 6502

    Jun 25, 2010
    I plan to use the iTunes match trick to upgrade all my low bit rate tunes to 256 kbps AAC using iTunes match.

    What about tunes that are 256 kbps mp3 and above. Are the iTunes store tracks still better? a) AAC is better than mp3 and b) iTunes tracks are made from masters and not the CD.

    I know that lossless tracks will be better, but are there any higher bit rate mp3 that are better quality than the 256 kbps AAC files from the iTunes store?
  2. macrumors 68020


    Nov 5, 2009
    What equipment are you using to playback the songs?
  3. macrumors Core


    Jul 24, 2006
    The Ivory Tower (I'm not coming down)
    Err... you seem to be confused. AAC is not lossless.
  4. thread starter macrumors 6502

    Jun 25, 2010
    I'm using an Apple TV 2 hooked up to a Denon 4308 receiver and Bower & Wilkins 683 speakers.
  5. macrumors P6


    Apr 1, 2005
    Space--The ONLY Frontier
    I don't think you will notice any difference.
  6. thread starter macrumors 6502

    Jun 25, 2010
    I know. My point is that I know lossless is better than 256 AAC, but is 256 AAC better than 320 mp3? Especially when the mp3 is ripped from a CD and the AAC is made by Apple straight from the master (higher sample rate) recording.
  7. macrumors Core


    Jul 24, 2006
    The Ivory Tower (I'm not coming down)
  8. thread starter macrumors 6502

    Jun 25, 2010
    That is almost certainly true. In my personal tests using successively higher bit rates from the same CD, I could tell the difference up to about 192 kbps but anything above that I couldn't distinguish. I guess I'm still interested in what is theoretically better as there might be some subtle differences you don't pick without doing comparisons across a wide variety of music.


    That's a useful opinion. I ripped about half my library at 320 k before hard drives got bigger and I did the rest lossless. My inclination is to just leave those alone, but if an easy opportunity presented itself I'd upgrade them to a higher quality.
  9. macrumors 68020


    Nov 5, 2009
    In all honesty it probably varies from song to song. The two different codecs treat different types of complexities within a file differently.

    I think the best option would be to not worry about it and give yourself some peace of mind.
  10. macrumors regular

    Jun 14, 2011
    Wrexham, North Wales
    I ripped my fave cds to apple lossless, off the top of my head its something like 928kbps - 500mb an album? ..up to 1GB, which obviously is quite a HDD muncher. I use bose ae2i headphones. Playing them on my iphone 4s was great coz it has no EU volume cap, since i bought the new nano though, the fricking volume has a hidden cap and so i cant really tell at that level. I no longer store music on my iphone, so i guess it all depends, if its portable music your after, keep 320kbps...theyre like 4x smaller file size, so you'll save more room.
    On a good home sound system you will notice difference at a decent volume level though. ...but you dont seem to be going for Apple lossless anyway?? Just do the itunes match thing, you won't notice.

    By the way, if you've 'downloaded' a file at say 198kbps, it will stay at that sound quality..even if changed to apple lossless. That only works direct from CD rip
  11. macrumors 604


    Jun 30, 2007
    We don't know this and its not likely that Apple has access to record compony property (master tapes) or needs/wants this. iTunes' songs would probably be at a 48KHz sampling rate if this were so. I bet the record companies send over CD quality (44.1/16) files (maybe even just a Redbook CD) for Apple to use.
  12. thread starter macrumors 6502

    Jun 25, 2010
  13. macrumors 604


    Jun 30, 2007
    I also want 48KHz or 96KHz 24 bit files offered by iTunes (I still but CD's because I don't listen to (much) lossy music). However the article clearly states (and it's 10 months old) that "...record labels are supposedly in discussions with Apple to begin offering 24-bit music files...". Thats says Apple doesn't have access to Master tapes (and likely never will since Master tapes are proprietary and used for storage) or even 92/24 file copies of the Master tapes at this time.
  14. macrumors 68020


    Oct 25, 2008
    ACC, Lossless, MP3

    You are going to get all sorts of responses (as you have seen)..here's my two cents -

    When possible, best to have "master" copies that are the highest bitrate possible. Lossless is ideal and given a choice between AAC 256 and mp3 320, I'd take AAC 256 as I can tell on some files a difference. Some files you wont hear much difference do to their range or the quality of the original.

    All my CDs are converted to Lossless. They play of course great.If I want, I can make AAC 256 from them with just the direct compression "loss."

    My downloads from iTunes remain at AAC 256 and I have from days gone by some MP3's that are ranging from 128 up to 320 bitrate. I hope to replace those later.

    The only advantage of Mp3 is if you have multiple "players" that don't play AAC files. Again, having a Lossless copy you can then make mp3 version for those players.

    I'll be short on the iTunes store - I have downloaded very good copies of songs at 256 and then all the older material (stuff from decades ago) sound horrible. However, LP version of the same album and some CDs were evidently cut from different "masters" than what iTunes got. I often think the problem remains with the high speed method of conversion. No one checks the quality and not all "masters" (I should say original source) are the same when it comes to transfers. So if you prefer more modern stuff, iTunes is pretty darn good. If you like say some Glen Miller or Ethel Waters or...its hit and miss.

    Bottom line - mp3=good, AAC 256 Superior and Lossless =can't be better
  15. thread starter macrumors 6502

    Jun 25, 2010
    phrehdd - that's my belief as well, that AAC is a superior format so the quality is better than mp3 even at a lower bitrate. I've decided not to mess with my 320k mp3's in any case, just because it's not worth the hassle.

    Instead of the next step up in sampling rate I wish the industry would start delivering multi-channel music. Most of us are hooked up to home theater type systems now and can take advantage of it, and the difference of moving from stereo to 5.1 music would almost certainly be more noticeable than a higher sampling rate or higher bitrate.
  16. macrumors 65816

    Jul 11, 2008
    After 192 kbps there is little difference between the two unless you have some really Hq headphones.

    That being said if you are only using ipods or AAC compatible media player I would pick AAC on the account that you'd save a little bit of space. If the choices were between mp3 at the same bitrate I'd pick mp3 for Max compatibility.

    At 128 kbps AAC is superior to MP3 no doubt.
  17. macrumors 6502

    Oct 22, 2005
    Also iTunes is not just pure CBR 256Kb/s. They are actually VBR and sometimes reach up to 320Kb/s. Found this out when getting iTunes match and my old CBR 256 mp3s were redownloaded as AAC and the files were more than marginally bigger on some songs (256kB/s is 256kB/s, regardless of file format, plus or minus a few bit difference for format meta data). Also my 3rd party sees them as VBR files.
  18. macrumors newbie

    Jan 3, 2011
    How about "Mastered for iTunes" - doesn't that equal to a vast amount of music on iTunes Store? When I listen to audio previews on iTunes Store (or Spotify) a lot sounds more "wider/clear" compared to equal tracks from my own mp3s/AAC's. Perhaps its my pure imagination or could it be that music on iTunes Store is ripped with superior gear, some "nice compression/EQ"?
  19. macrumors 6502a


    Aug 8, 2006
    Lodi, CA
    Theoretically the 320 MP3 will ALWAYS be better. But that is purely in theory. In the real world it would be entirely a case by case basis. Song A might sound better with the AAC iTMS copy in "only" 256kbps where song B from a different album will actually sound "better" in 320 MP3. But better is subjective and rarely can anyone tell the difference without $1000 audio components.

    From FLAC to V0 MP3 I can tell subtle differences, but not nearly enough to warrant the extra disk space.

    As you said before, anything above 192 will sound good. 128 on the other hand, I can almost always tell the difference.
  20. macrumors 6502

    Oct 12, 2011
    It's all about the quality of the rip and the encoder.

    If all conditions were "perfect" the 320kbps rip would sound better. But if you don't really know what you are doing, it is possible to end up with a 320kbps rip that sounds inferior to a well-done 192 or even 128 rip.

    I'd also like to interject that I'd wager money that most people who claim they can tell the difference between a good 320 rip and a lossless FLAC copy or even the original source are full of it.
  21. macrumors 6502a

    Oct 26, 2007
    Sydney, Australia.
    I'm full of it.

    I can tell the difference between 192 aac and apple lossless on my equipment. Lossless> Apogee Duet firewire DAC> Burson HA-160 headphone amp > Sennheiser HD-600.

    and similar quality loudspeaker systems.
  22. TyroneShoes2, Jul 27, 2012
    Last edited: Jul 27, 2012

    macrumors regular

    Aug 17, 2011
    Is that a personal theory? If bit rate were the only variable, yes, 320 would be better. But there are other variables. When there are other variables, "ALWAYS" goes right out the window.

    For example, is a 9 GB episode of Fringe better than a 7 GB episode of Fringe? Absolutely not if the first copy is MPEG-2 and the second copy is MPEG-4 AVC, even if from the same original. The critical variable here is that MPEG-4 is a better codec; it can either do a better job at the same bit rate, or an equivalent job at a lower bit rate.

    Its the same with AAC vs. MP3. AAC is a better codec, and can also either do a better job at the same bit rate, or an equivalent job at a lower bit rate.

    So the OPs question, which is better, MP3 at 320 or AAC at 256, is still an open question. 320 is absolutely not ALWAYS better.

    With all else held equal, it was well accepted back when Apple started using AAC that a 128 kbps AAC was equivalent to a 160 kbps Fraunhofer MP3 (other versions of MP3 were inferior). If the math is linear, that would make a 256 AAC equivalent to a 320 MP3. But then development on MP3 has stagnated while there have been a number of improvements to AAC since Apple first started using it in 2003.

    That would tend to support the theory that the 256 AAC Apple ripped from a CD would actually be better than the 320 MP3 that the OP ripped from a CD, assuming the AAC used Apple's most modern flavor of AAC. And you can probably bet that Apple is not just using the consumer encoder available in every free copy or iTunes to build their library, but top-shelf encoding hardware. That equals even better quality.

    And if Apple really is getting the masters, which is their stated intent, that will be significantly better. One of the basic rules of encoding is that when you restrict to a severely-low bit rate in a lossy format such as consumer AAC/MP3, what really makes a difference is the quality of the original. And that is exactly why they are doing it.

    Problem is, I don't think that program is all that ramped up quite yet, and it will probably take a few years for them to really get it pervasively through their library (which is why although I intend to do iTunes Match, I am waiting).

    A CD is 16 bit at 44.1 Khz. That's an equivalent uncompressed bit rate of 1,411.2 kbps (for stereo). Modern masters are 24 or even 32 bit at 192 KHz, which can give them an uncompressed bit rate up to 12,288 kbps. This means more samples more often, up to a factor of times 8.6, or even better. It also means quantization steps orders of magnitude less far apart. That means a whole lot fewer or smaller rounding errors during final encoding, which means a whole lot fewer audio artifacts when compressed at an equivalent 256 kbps bit rate.

    We might actually get back all of the things we have given up for the portability of MP3s, including stereo imaging, separation, real crisp highs instead of swishy highs, and real solid bass instead of mushy bass or bass MIA. Maybe even some dynamic range.
  23. macrumors regular

    Aug 17, 2011
    The biggest secret to "knowing what you are doing" is mostly simply to get the input encoding level correct. If you normalize the digital master so that the highest peak is at 0 dBFS, and even limit some of the highest peaks beforehand, you can then take advantage of every least-significant bit during encoding, especially if the original digitization was done at the optimum level. That minimizes the quantization noise floor and means you are utilizing more of the available bits in every sample more effectively, as well as creating the fewest rounding errors, resulting in the best-quality product possible.

    And if you are using 16 bit, which implies a noise floor of -96 dBFS, another trick is to use a hard gate at -95 and simply remove any potential contribution from quantization noise in the original file (which only works if your system s/n is lower than that). That will give you another 2 to 3 dB of dynamic range above the final noise floor in the encode.

    And if you are using a good encoder, it is then hard to screw things up quite that badly. But if you just manually ride levels at approximately -18 dBFS, it won't be all that great. Its a combination of knowing how and taking the care to do it right.

    I really hope you are not going to cling to that. If you put either one of them into a quality stereo system, it is difficult to immediately declare "that's the rip!" or "that's the original". It's not even easy in a double-blind study where you play first one, then the other, and then ask which is which. But if you play them simultaneously and switch back and forth between them, it is abundantly clear which is the original, even to tin ears.

    So you can give me access to your PayPal account whenever you are ready.;)
  24. macrumors newbie

    Jul 27, 2012
    FLAC/ALAC/AIFF will always be the best.

    But no one needs such quality. Even Audiophiles can't tell the difference with 256 and above. 256 is enough. In fact, 128 should be.
  25. macrumors 68040


    Jun 16, 2007
    My solution throughout the years:

    1. Rip in FLAC or Apple Lossless (usually this since my move to Apple)
    2. Convert from Lossless to 224Kbps VBR.
    3. Keep both copies, the MP3s for portable use and lossless for higher end equipment.

    Hard drive space is so cheap nowadays that you can't complain about lossless taking up space.

    Also nice thing about having a Lossless version is that compressed formats change over time and you can always go back and just do a batch convert to a new format (MP4 will be the new standard soon, but MP3 still is on it's two toes for now.)

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