Bitrate question... 320, 192, 256, 128?? ACC?

Discussion in 'Mac Apps and Mac App Store' started by vitog123, Oct 18, 2011.

  1. vitog123 macrumors 6502

    Aug 30, 2009
    Can someone give me a quick explanation on all this?

    Ive been using mp3's for years and have always burned my CD's to 320 or when downloading them chose the highest bitrate possible.

    Highest bitrate means best sounding, correct???

    What is ACC and why does iTunes want to convert it to 128?

    please advise.. I have about 10 gb of music that I have not converted and im wondering what is the best way to maintain my music library.

    btw, im on windows 7 :( if that makes a difference.
  2. saberahul macrumors 68040

    Nov 6, 2008
    The higher the bit-rate, the better the sound quality, the higher the song capacity. Bitrate is essentially bits per second - hence higher is better. Frankly though, I could never notice a difference (to the ear) between 128 and 320. Although, I usually stick with 256.
  3. vitog123 thread starter macrumors 6502

    Aug 30, 2009
    what happens to the file if i let itunes convert it to acc?
  4. dholaday macrumors member


    Mar 27, 2009

    First, I believe you mean AAC, not ACC [unless you're playing sports].

    Second, below is from iTunes Help:

    "You can convert a song to a different file format (and keep a copy of the original). For example, you can save a copy of a compressed song file such as MP3 or AAC in an uncompressed song format (AIFF or WAV).

    When converting from a compressed to uncompressed file format (for example, from MP3 to AIFF), you shouldn’t notice any reduction in sound quality. However, when converting between compressed formats (for example, MP3 and AAC), you may notice a reduction in the sound quality. For the best results, if you want your music encoded in a different file format, import the music again from the original source using the new encoding format."

    As Apple points out, you will generally get downgraded audio when you convert from one lossy file format [such as MP3] to another [such as AAC]. FWIW, Apple thinks AAC is a better lossy compression scheme than MP3.

    Third, if you are happy with the sound quality of your MP3s, there is no reason at all to convert them. But you may want to import new material as 256 AAC to improve quality and save space.

    Again, FWIW, Apple has said in the past that 256 AAC sounds as good as a CD -- I have no idea if they have done in double-blind testing to support that statement.

    Finally, again FWIW, I've chosen to import all my CDs in AIFF [a lossless format]. Storage is way cheap, and that way I can always re-create a bit-for-bit duplicate of the original CD. But it severly limits the amount of music I can load onto an iPod or iPhone.

    my 2-cents

  5. aarond12 macrumors 65816


    May 20, 2002
    Dallas, TX USA
    I can hear the compression noise from poorly-compressed audio files quite easily. That being said, I have difficulty hearing any noise from 256Kb AAC files ripped from CD.

    If you want to hear the compression noise yourself, try this: Play your MP3 files through a sound system with Dolby ProLogic surround sound enabled. Unplug the front and center speakers, leaving only the surrounds attached. This emphasizes the compression noise.

    You will be shocked at how noisy many MP3 files are. To me, it sounds like a watery brook flowing under the music.
  6. gorskiegangsta macrumors 65816


    Mar 13, 2011
    Brooklyn, NY
    The higher the bitrate, the better the quality. Theoretically, at least. In reality, you will not notice the difference when listening with most headphones and speakers. The difference becomes noticeable at high amplifications (i.e. concerts/DJ gigs, where the sound is delivered over relatively large [100ft+] distances). I, personally, try to keep my music collection at 256kbps+ bitrate since I mostly have electronic/trance music which noticeably degrades at lower bitrates.

    AAC (.M4A, .AAC) is just another audio codec, (most popular being LAME MP3 (.MP3)). It delivers better quality over the same bitrate/file size than LAME MP3. iTunes has the option to convert to 128kbps AAC to potentially allow you to save space on your mobile device.
  7. reekster macrumors newbie


    Oct 19, 2003
    Big Blue Marble
    Hard drive space is so cheap now, I started just importing as full AIF files a few years ago. Look at things you did years back and how crummy the resolution seems now. Think about the future.
    AIF on the mac gives you the best options for making audio CD's or converting to MP3 when/if you need.
  8. eric/ Guest


    Sep 19, 2011
    Ohio, United States
    Just keep on trucking at 320kbs MP3s and you'll be good to go. No reason to convert to AAC, especially when you'll lose sound quality in the process. The only other suggestion I would have if you aren't satisfied with 320kbs is to download/save them in a lossless format. But for the most part without high end audio systems you are unlikely to hear a difference between 320kbs and FLAC or Apple lossless or whatever else.
  9. vitog123 thread starter macrumors 6502

    Aug 30, 2009
  10. marcusj0015 macrumors 65816

    Aug 29, 2011
    I personally use ALAC. because the MP3 and possibly AAC, psychoacousticanalysis ****s the music up, it moves some of the background music into the vocal range and muddies it up. for me anyway.

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