MP3 Artifacts

Discussion in 'Recording/Live Sound' started by mcknigs, Apr 6, 2015.

  1. mcknigs

    mcknigs Supporting Member

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    I've been doing some recording over the last couple years (using Reaper) and converting mixed files to MP3s. Because I often email these to people to learn the songs, I tend to keep the resolution down to 128K. Sometimes I hear weird phasing effects that I'm not used to hearing from MP3s (including 128K) made from commercial recordings. This usually happens when the original material has real or artificial tight delays. For example, I've taken, say, a rhythm guitar, copied it, nudged the copy a few (~20) milliseconds later, then panned them hard left and right. I guess you could call it cheesy stereo simulation but it sounds fine when listening to the mix as a wav file. It doesn't sound like actual simulated stereo recordings of the '60s that I've heard, which really do sound weird to me.

    This weekend I recorded an acoustic with a single mic in a space with an angled ceiling a few feet away, providing fast reflections. It sounded like an acoustic guitar in a small bright room, which it sort of was. Again, it sounded fine as a wav file, and in a 196k MP3, for that matter, but in a 128k MP3 file I could easily hear strange phasing artifacts.

    So why am I hearing these from my own 128K MP3s when I don't hear them from other 128K MP3s? I don't think it's just that I'm listening more closely. I doubt it's that the commercial recordings were engineered to avoid the MP3 artifacts, as much of the music I listen to predates MP3s. As far as I know the MP3 encoder is the same LAME encoder I use in other situations to convert WAVs with no problems. Maybe it's something about the resolution I'm using to record in Reaper not getting along with MP3 encoding?

    Any ideas? Sorry I don't have an example, though I could probably make one if there is interest.
     
  2. camstudio

    camstudio Member

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    It may just be the mp3 algorithm. If your wav is 24bit you could try bouncing it to 16bit first to reduce the amount of information then convert to mp3.
     
  3. zenmindbeginner

    zenmindbeginner Member

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    VBR usually produces lower quality but smaller file sizes
    CBR is not as efficient in terms of creating the smallest files but it's quality is consistent

    ABR is sort of a compromise between the two.

    LAME isn't as good for anything under 160K as the Fraunhofer encoder IMHO.

    ... but then again, Fraunhofer's file sizes seem to be larger than LAME's which could indicate a slightly better sonic quality.

    I know there are people out there who tout LAME's superior compression and constant updates as being the best MP3 encoder out there but in my experience, the compression tends to be too heavy handed. Fraunhofer's encoder creates large and lumbering MP3 files but the sonic quality is never in question.
     
  4. mcknigs

    mcknigs Supporting Member

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    I could see how to change the encoder Reaper uses. The big question for me is still "why does LAME work for so many recordings but not mine?"
     

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