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OT: Audacity noise removal question

Discussion in 'Electronic Design' started by Joerg, Mar 21, 2012.

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  1. Joerg

    Joerg Guest

    Question to audio folks:

    I am trying to transfer a memorial service to CD, for folks far away who
    could not attend. Have the MP3 file, wanted to equalize the audio and
    remove hum. All the effects options including "noise removal" are
    grayed out. Looking on the web I found only hints that this can happen
    if you have multiple installs and the config file is being screwed up
    but I don't have that.

    What gives?
  2. Don Y

    Don Y Guest

    Hi Joerg,

    For the authoritative answer, grep(1) the sources to see what
    enables/disables that particular option? (at least it's an
    approach that *you* can control instead of hoping for the
    "right"/appropriate answer from a third party)

    [Sorry, I don't use FOSS audio tools so don't have the source
    on hand :< ]
  3. Joerg

    Joerg Guest

    I am not enough of a SW guru to easily figure that out, let alone
    correct a bug. Plus I thought it's something easy, like "Oh, just turn
    on the XYZ obfuscator". All I want is to do a widow a favor.
    Unfortunately what happened is that someone mucked with the big mixer
    and you can't find that out until someone starts to speak at the pulpit.
    Took me 2-3 minutes, so I want to equalize that part and get the hum out
    which is rather annoying for that speech.
  4. Tim Williams

    Tim Williams Guest

    Try playing with plugins -- there's probably something that didn't come with

    I haven't used Audacity in a while so I forget if plugins are listed on a
    dialog or the website or what, and where to install them, etc... I do
    remember not being able to export MP3, then downloading the codec DLL and
    having it available pretty easily.

  5. Don Y

    Don Y Guest

    Hi Joerg,


    This suggests you're missing some aspect of the uesr interface
    design philosophy. E.g., have you selected the portion of the
    waveform to which you want to *apply* the effect?
    Usually doesn't require more than "a deductive mind" to look
    at the "things" mentioned/suggested in the code for possible
    "inspiration" :>
    No good deed goes unpunished! :>
  6. MarkK

    MarkK Guest

    Audacity effects processing is "off line"

    you select a section of the file and select an effect and tell it toprocess,
    then you can hear the result when it is done.

    There is a preview function but this offline processig is clunky.

    Try "ntrack studio"

    its not free but it is inexpensive.

  7. Ecnerwal

    Ecnerwal Guest

    I'd remove and reinstall. I use the program, but I have not had the
    problem you are having. Or install on a different computer.

    Then again, it could be that you need to convert to a different format
    before the effects are available - WAV or AIFF (you can go back to MP3
    at the end.) I don't do squat with MP3s, so that's just a guess. Well,
    probably not - I finally found an MP3 lurking here and all options
    including noise removal are still happy with it.
  8. Don Y

    Don Y Guest

    Hi Mark,

    Whether it the results are available "interactively" or not isn;t
    the question. Does the UI *allow* you to invoke effects without
    previously selecting a track or portion of a track on which
    the effect will be applied?
    If the previous selection process is a prerequisite for making
    the effect choice possible, then I would expect effects to be
    disabled (gr[ae]yed out in the menu/toolbar/wherever) *until*
    that selection is made.

    (otherwise, the user clicks on an effect and you have to prompt
    him to select an appropriate portion of the audio)

    Dunno, I have no experience with Audacity. My comments are
    just reflections of other similar tools (audio/video) that
    I've used ("Why can't I click on this menu entree? What
    is it waiting for me to do in order to *allow* me to make
    that choice??")
    This was common of older processing tools -- that didn't
    want to "look bad" if running on hardware that wasn't
    fast enough to render the changes in real time (or, that
    had to make multiple passes over the "original")

    It's also more in line with the UN*X philosophy of plumbing
    together smaller modules to achieve a greater functionality.
  9. Joerg

    Joerg Guest

    Yes, I did that.

    Like a guy back at our university. "There is some slight pinging that
    sounds like a piston rod bearing. Let's take the engine apart and have a

    Nah, it ain't that bad :)
  10. Joerg

    Joerg Guest

    Well, gents, found it: One cannot just open a MP3 file because then
    nothing other than play and stop and stuff works. One has to import the
    file instead.
  11. Try a freeware editor, and re-create the pre-edited MP3 file with that
    (once you complete the job of course), then return to being less than
    audacious, and create the CD with the under whelming (again) Creative

    I think (know) Creative has an updater thingy that finds all your
    Creative HW and then hunts up drivers and updates for you.

    Also, if you have the file in a more raw form, it may be more
    "editable" than an already (poorly) compressed MP3 datagram. Not saying
    you did something poor, but that MP3 file format itself ain't that great.

    Doesn't matter every other Joe embraced it.

    Real pro editors do not. Maybe it is grayed because of the type of
  12. WoolyBully

    WoolyBully Guest

    A Windows 95 mentality idiot.
  13. Joerg

    Joerg Guest

    Unfortuantely MP3 is all I've got.

    Meantime I found out what it was: Loading a file with "Open" makes it
    totally non-editable in Audacity. It has to be loaded with "Import",
    then it all works.

    Well, sorta. The noise "learning and elmination" feature produced a
    horrible sound, like shortwave with lots of fading. Now I am trying the
    notch filter to at least get the 60Hz stuff out, up to the 9th harmonic
    or so. The issue is that part of the service was recorded at a very low
    volume because someone had messed with the mixer. Unfortunately one
    can't find out about that before the first persons starts with a eulogy.
    At least not at a memorial service where relatives come very early.
  14. miso

    miso Guest

    The only time the effects are grayed out for me is when I don't have a
    file open. There is no problem editing mp3 files, though you will
    probably want to export wave to burn the CD. [It is best to avoid
    recompressing a compressed file.] When I open a MP3, it is converted to
    32 bit float in the editor itself.

    I would suggest just using a notch at 120Hz and roll off starting at
    100hz. That noise filter is kind of flaky. You could try noise gating.

    I am running beta 1.3 on win7. I have it on opensuse as well, but that
    PC isn't booted.

    I see Thompson was being as useful as he is capable of being, which of
    course is totally useless.
  15. miso

    miso Guest

    I can open a MP3 just fine. I wonder if your lame and FFMPEG is set up
    ok. You can go to edit->preferences->libraries and take a look.
  16. miso

    miso Guest

    Most people set up audacity to work in 32 bit float. This way
    mathematical processing noise doesn't build up. It can't edit mp3
    "natively." When you open a mp3, it goes "linear" for processing, then
    gets a fresh MP3 encoding if you save it as mp3. This is the dreaded
    cascade of compressor problem.
  17. Can you ask the person to do you a big favour and read it again?
  18. JW

    JW Guest

    Actually, it's you that is the idiot yet again. Ever hear of other
    programs over-writing DLLs?

    You Big AlwaysWrong Dummy.
  19. Jasen Betts

    Jasen Betts Guest

    Try pressing the stop button?

    The effects menu content seems to be disabled during playback, even if paused.
    I guess you've figured that out by now.
  20. Jasen Betts

    Jasen Betts Guest

    I'm not seeing that here, for me open and import both allow editing.
    (Version is "1.3.12-beta!" ) I have lame installed (which may make a difference)
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