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  1. #1
    Simon Turner
    Guest

    MP3 quality poor due to low volume levels, notcompression.

    Jason.. the immediate goal is to avoid clipping (distortion), not to
    "normalise" the whole collection.
    I am not "normalising", as I understand this can irreversably change the MP3
    files. Replay Gain does not "normalise". I have learnt this from the
    Hydrogen Audio, MP3Gain and Replay Gain web sites.
    The problem seems to be that when files have had clipping removed by MP3Gain
    the volume level is reduced and is then lower than hardware devices like the
    iPod and the Squeezebox are designed for. So the output thses devices then
    provide is not sufficient to properly drive the input of many hifi
    amplifiers. This results in a thin and weedy sound. And the only way to get
    any volume is to crank up the volume on the hifi amp much more than one
    would for the other peripheral devices (CD, Tuner etc).

    Buying a more powerful amplifier will not change anything, just give me a
    louder weedy sound.

    I am just looking for a reason why, in my case, the iPod and the Squeezebox
    do not seem to provide as high a level input to my hifi amplifier as all my
    other (more standard) devices.

    I am perplexed that there are not many others who have the same problem and
    of course this worries me. I would be quite interested if the person who
    said something like "I can't see how ripping through EAC could introduce
    clipping" would run his ripped files through MP3Gain
    (http://mp3gain.sourceforge.net) and read the programs help file.

    Perhaps I ought to disregard MP3gain (Replay Gain) and all that is
    recommended at Hydrogen Audio and just increase the gain on my files to
    levels above clipping... but... although I cannot hear ANY distortion due to
    clipping when MY MP3 files are played through my computer the distortion is
    very obvious when the same files are played on my iPod.

    My post is not meant as a criticism of the Slim devices at all. I am just
    looking for help.

    Simon
    Brighton UK.




    -----Original Message-----
    From: discuss-bounces (AT) lists (DOT) slimdevices.com
    [mailto:discuss-bounces (AT) lists (DOT) slimdevices.com]On Behalf Of Jason
    Sent: 31 December 2003 23:32
    To: 'Slim Devices Discussion'
    Subject: [slim] MP3 quality poor due to low volume levels,
    notcompression.


    What is the whole goal here? I just rip/encode with EAC and LAME. I have a
    few albums that have slightly lower volume than others but I don't see the
    need to normalize my whole collection down to 89db just to prevent having to
    adjust the volume knob once in a while.

    So again, what is the goal here? If you are doing normalization there are
    lots of additional factors that can be screwing things up for you.

    If you are saying that the squeeze is not loud enough once everything is
    normalized, welcome to the wonderful world of normalization, you can always
    buy a more powerful amplifier.

    -----Original Message-----
    From: discuss-bounces (AT) lists (DOT) slimdevices.com
    [mailto:discuss-bounces (AT) lists (DOT) slimdevices.com] On Behalf Of Jason Holtzapple
    Sent: Wednesday, December 31, 2003 2:19 PM
    To: Slim Devices Discussion
    Subject: [slim] MP3 quality poor due to low volume levels,
    notcompression.

    --- Caleb Epstein <cae (AT) bklyn (DOT) org> wrote:
    > On Wed, Dec 31, 2003 at 08:40:20PM -0000, Simon Turner wrote:
    >
    > > Hi Jason, Volume level is set to max. I use Constant Gain as it
    > > enables me to be sure I have got the cd I am ripping to the highest
    > > volume without icurring clipping in any individual track, whilst
    > > still retaining the different volume levels between tracks. Usually
    > > i find that just going one step down (i.e. -1.5db) gets rid of any
    > > clipping introduced in the ripping process. I'm not too sure if
    > > album gain does exactly this.

    >
    > How could ripping a CD introduce clipping? You're just
    > extracting the WAV data off of the disc. If you have a decent
    > drive or use the right software, its a perfect copy.


    Probably not the ripping, but the encoding. I have plenty of
    EAC/LAME --alt-preset standard encodes that are clipped
    'out of the box' according to mp3gain.

    > I expect album gain normalizes an entire disc as a single
    > unit, so the highest peak of the entire album is at 0db. You
    > seem to be normalizing on a per-track basis, so the highest
    > peak of every track is at 0db.


    It might help if Simon tells us what he's trying to
    accomplish: a similar volume throughout his collection
    or simply trying to reduce clipping.

    --Jason

    __________________________________
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    Find out what made the Top Yahoo! Searches of 2003
    http://search.yahoo.com/top2003

  2. #2
    Craig Brannan
    Guest

    MP3 quality poor due to low volume levels, notcompression.

    Still trying to picture what exactly a weedy sound is...

    but in any event - it seems like you're going through a somewhat
    laborious process to eliminate distortion - yet that very process seems
    to be adding it's own greater distortion (i.e. deviation from the
    original source).

    The easiest answer would be to abandon the extra steps. MP3 is a lossy
    compression process and will therefore add some form of distortion to
    your music. Is it possible that what you describe as clipping is just
    the distortion (loss) inherent in the MP3? If so then no amount of gain
    adjustment will correct it and the only real solution would be to
    switch to a lossless encoding format.

    Does everything from the squeeze sound weedy - or is it just the gain
    adjusted files?

    craig.

    On Dec 31, 2003, at 9:52 PM, Simon Turner wrote:

    > Jason.. the immediate goal is to avoid clipping (distortion), not to
    > "normalise" the whole collection.
    > I am not "normalising", as I understand this can irreversably change
    > the MP3
    > files. Replay Gain does not "normalise". I have learnt this from the
    > Hydrogen Audio, MP3Gain and Replay Gain web sites.
    > The problem seems to be that when files have had clipping removed by
    > MP3Gain
    > the volume level is reduced and is then lower than hardware devices
    > like the
    > iPod and the Squeezebox are designed for. So the output thses devices
    > then
    > provide is not sufficient to properly drive the input of many hifi
    > amplifiers. This results in a thin and weedy sound. And the only way
    > to get
    > any volume is to crank up the volume on the hifi amp much more than one
    > would for the other peripheral devices (CD, Tuner etc).
    >
    > Buying a more powerful amplifier will not change anything, just give
    > me a
    > louder weedy sound.
    >
    > I am just looking for a reason why, in my case, the iPod and the
    > Squeezebox
    > do not seem to provide as high a level input to my hifi amplifier as
    > all my
    > other (more standard) devices.
    >
    > I am perplexed that there are not many others who have the same
    > problem and
    > of course this worries me. I would be quite interested if the person
    > who
    > said something like "I can't see how ripping through EAC could
    > introduce
    > clipping" would run his ripped files through MP3Gain
    > (http://mp3gain.sourceforge.net) and read the programs help file.
    >
    > Perhaps I ought to disregard MP3gain (Replay Gain) and all that is
    > recommended at Hydrogen Audio and just increase the gain on my files to
    > levels above clipping... but... although I cannot hear ANY distortion
    > due to
    > clipping when MY MP3 files are played through my computer the
    > distortion is
    > very obvious when the same files are played on my iPod.
    >
    > My post is not meant as a criticism of the Slim devices at all. I am
    > just
    > looking for help.
    >
    > Simon
    > Brighton UK.
    >
    >
    >
    >
    > -----Original Message-----
    > From: discuss-bounces (AT) lists (DOT) slimdevices.com
    > [mailto:discuss-bounces (AT) lists (DOT) slimdevices.com]On Behalf Of Jason
    > Sent: 31 December 2003 23:32
    > To: 'Slim Devices Discussion'
    > Subject: [slim] MP3 quality poor due to low volume levels,
    > notcompression.
    >
    >
    > What is the whole goal here? I just rip/encode with EAC and LAME. I
    > have a
    > few albums that have slightly lower volume than others but I don't see
    > the
    > need to normalize my whole collection down to 89db just to prevent
    > having to
    > adjust the volume knob once in a while.
    >
    > So again, what is the goal here? If you are doing normalization there
    > are
    > lots of additional factors that can be screwing things up for you.
    >
    > If you are saying that the squeeze is not loud enough once everything
    > is
    > normalized, welcome to the wonderful world of normalization, you can
    > always
    > buy a more powerful amplifier.
    >
    > -----Original Message-----
    > From: discuss-bounces (AT) lists (DOT) slimdevices.com
    > [mailto:discuss-bounces (AT) lists (DOT) slimdevices.com] On Behalf Of Jason
    > Holtzapple
    > Sent: Wednesday, December 31, 2003 2:19 PM
    > To: Slim Devices Discussion
    > Subject: [slim] MP3 quality poor due to low volume levels,
    > notcompression.
    >
    > --- Caleb Epstein <cae (AT) bklyn (DOT) org> wrote:
    >> On Wed, Dec 31, 2003 at 08:40:20PM -0000, Simon Turner wrote:
    >>
    >>> Hi Jason, Volume level is set to max. I use Constant Gain as it
    >>> enables me to be sure I have got the cd I am ripping to the highest
    >>> volume without icurring clipping in any individual track, whilst
    >>> still retaining the different volume levels between tracks. Usually
    >>> i find that just going one step down (i.e. -1.5db) gets rid of any
    >>> clipping introduced in the ripping process. I'm not too sure if
    >>> album gain does exactly this.

    >>
    >> How could ripping a CD introduce clipping? You're just
    >> extracting the WAV data off of the disc. If you have a decent
    >> drive or use the right software, its a perfect copy.

    >
    > Probably not the ripping, but the encoding. I have plenty of
    > EAC/LAME --alt-preset standard encodes that are clipped
    > 'out of the box' according to mp3gain.
    >
    >> I expect album gain normalizes an entire disc as a single
    >> unit, so the highest peak of the entire album is at 0db. You
    >> seem to be normalizing on a per-track basis, so the highest
    >> peak of every track is at 0db.

    >
    > It might help if Simon tells us what he's trying to
    > accomplish: a similar volume throughout his collection
    > or simply trying to reduce clipping.
    >
    > --Jason
    >
    > __________________________________
    > Do you Yahoo!?
    > Find out what made the Top Yahoo! Searches of 2003
    > http://search.yahoo.com/top2003
    >

  3. #3
    roy@rant-central.com
    Guest

    MP3 quality poor due to low volume levels, notcompression.

    On Wednesday 31 December 2003 11:00 pm, Craig Brannan wrote:
    > Still trying to picture what exactly a weedy sound is...
    >
    > but in any event - it seems like you're going through a somewhat
    > laborious process to eliminate distortion - yet that very process seems
    > to be adding it's own greater distortion (i.e. deviation from the
    > original source).
    >
    > The easiest answer would be to abandon the extra steps. MP3 is a lossy
    > compression process and will therefore add some form of distortion to
    > your music. Is it possible that what you describe as clipping is just
    > the distortion (loss) inherent in the MP3? If so then no amount of gain
    > adjustment will correct it and the only real solution would be to
    > switch to a lossless encoding format.
    >
    > Does everything from the squeeze sound weedy - or is it just the gain
    > adjusted files?


    FWIW, I just completed an mp3gain pass over my whole ripped collection because
    I was tired of reaching for the volume control. I didn't try to maximize
    anything, but just processed everything an album at a time (to retain the
    relative gain across each album's tracks). Most of my stuff was reduced.
    (Barenaked Ladies' 'Stunt' dropped 5 dB) Some was boosted (Planet P Project
    raised 1 dB) But all of it sounds as good as before processing. Only the
    relative volume levels changed; there was no noticable change to the
    character of the sound. And the relative output level is still comparable to
    other inputs on my receiver.

    Granted, my ears are far from golden. But considering that mp3gain does
    nothing more than change the relative amplitude of the signal, I honestly
    can't understand how that would change the percieved "quality" of the
    reproduction. If Simon is truly experiencing a noticable change in timbre
    such as he describes, I'd think that there is something besides gain
    adjustment at play.

  4. #4
    Nicolas Guillemain
    Guest

    MP3 quality poor due to low volume levels, notcompression.

    Le 01/01/2004 à 06:35:17, Jason écrivait :

    > MP3gain does not FIX clipping [...]


    Well, it does - in a way.

    Clipping is somehow inherent to MP3 decoding. As I understand it (but
    don't quote me on it and check out hydrogenaudio.org), rounding errors
    when the file is decoded are so that a source track that peaks at -0.1dB
    will most probably clip at 0dB when decoded. It tends to be a problem
    with most modern music, which is generally mastered with very limited
    headroom, if any - so the resulting MP3s are very likely to clip when
    played back, even if there's no actual clipping in any of the MP3 frames.

    So you're right, using MP3Gain on these files does not actually "fix"
    clipping, as there is no actual clipping to begin with, at least not in
    the files themselves - what it does is apply ReplayGain normalization
    (or "loudness" normalization, as opposed to peak normalization) in such
    a way that playback will no longer induce clipping. It's a lossless and
    completely reversible process, so you can always go back and adjust the
    target volume if the result sounds too "thin" for you, whatever that
    means.

    As several posters already pointed out, hydrogenaudio.org is pretty much
    the definitive reference on those tricky subjects. There's more info
    there than you can shake a stick at - it's really worth checking out the
    forums if you want to learn more on the fine art of audio encoding.

    Also, the MP3Gain help file has a good primer on why loudness
    normalization is better than standard peak normalization, again worth
    checking out if you're not sure what ReplayGain utils can do for you.

    Be seeing you,
    Nicolas
    --
    http://www.grenouille.com - la météo du net

  5. #5
    T
    Guest

    MP3 quality poor due to low volume levels, notcompression.

    > I am perplexed that there are not many others who have the same problem
    and
    > of course this worries me. I would be quite interested if the person who
    > said something like "I can't see how ripping through EAC could introduce
    > clipping" would run his ripped files through MP3Gain
    > (http://mp3gain.sourceforge.net) and read the programs help file.


    Interesting, I just ran some 0dBFS mp3 files through mp3gain (various
    sine-waves and sweeps, 20 files). It indicated that all of the files were
    clipped, despite the fact that none of these files are clipped when playyed!
    I design professional audio broadcast equipment for a living, so I do know
    what I am talking about.

    Tom

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