Voice crackling

  • sotka

    Recently downloaded and tested Mumble, it seems like a program with very low
    lag and great voice quality. However, we (2 people) noticed a problem with
    voice: when pronounciating words strongly, the voice cracks a bit. It is hard
    to describe it, but it is a high pitch sound which doesn't last long. And
    being Finnish, we have a lot of strong pronounciations in our language, so the
    problem occurs quite often.

    We noticed another problem while playing CoD4, but can't really point out if
    it was Mumble, Punkbuster, or some other thing. Basically it made the game
    stutter sometimes - not very often, but sometimes. We haven't had this problem
    before, so we suspect it is Mumble, but as I said, Punkbuster or some other
    program could be affecting it too. Is this a known problem?

    Our computers are quite good (dual/tri-cores, 2/4gb ram, etc), so the problem
    shouldn't be there.

  • Noel Houck
    Noel Houck

    Turn off mic boost in Windows. The crackling problem is from too much mic

  • sotka

    I don't have mic boost enabled, I couldn't even use since I get a static
    background voice then. On the other hand, the guy who tested the program with
    me, has mic boost enabled. We'll try lowering the mic volume.

  • sotka

    Nope, that didn't help. I reduced mic volume to as low as 30% (it was 100%,
    but the problem persists. I tried to put the volume to 10%, but then my sound
    became distant, low and as if I was speaking from a tin can.

  • Noel Houck
    Noel Houck

    Try this:

    Enabled advanced mode.
    Go to Audio Input, set Aplification to 1.
    Turn up Mic input volume to 50.
    Run audio config wizard.

  • sotka

    I tried to put it to 1, but then my mate didn't hear anything. Tried 2, and
    now it works! Didn't even need to turn volume down to 50, 100 works as well.

    What does that Amplification do, btw?

  • Noel Houck
    Noel Houck

    It boosts your mic input signal. Which in your case was too high.

  • Senve

    I've done quite much testing with this problem. The problem is Mumble and its
    not mic boost or too loud mic input volume.

    The amplification setting amplifies the crackle too. So, by minimizing the
    amplification the crackle is less loud. However, its still louder than normal
    speaking volume and this does certainly not help those users who need
    amplification to be heard.

    I'm finnish too and it happens on loud vowels in the beginning of the
    transmission. (Jitter buffer does nothing, or output delay). I've heard some
    of the crackles after some seconds of talking but the majority occurs with
    first couple of words of the transmission.

    This is also happening very often. You hear it randomly every 5-20 seconds.

    The crackles can be heard in audio wizard. When i record my mic with Audacity
    at the same time I try to provoke them in audio wizard, there are no crackles
    in the audacity recording but i hear them in mumble. Audio wizards volume
    indicator is about at half at maximum, it never went to red. Testing done with
    boost on and off. The crackle is somewhat same than when you yell to the mic
    very closely, but not exactly the same. Its more of a "pop" or fast one vowel
    crackling This happens on desktop microphones and headset microphones.

    I can provoke the crackle quite often when i'm silent for a while and then
    loud finnish vowel ini some word, I believe it has something to do with gain
    control and normalization. I'm not sure but it seems like there are a little
    less crackles when amplification is low. They happen on speex and celt with
    all audio packet sizes.

    This is MAJOR problem with (finnish?) Mumble users. I hear it on every server,
    at least 50-75% of users crackle (some more, some less; (N = ~5 servers, at
    least 70 different users)).

  • Noel Houck
    Noel Houck

    Well another reason why this might happen is that your sound system cannot
    keep up processing sound data. This tends to happen on lower quality
    motherboards. You may notice this especially while playing games or doing
    things which use the graphics system where both subsystems are competing for
    use of the motherboard channels. I have this same problem on a low end
    computer I use for my entertainment system. If I drag a window to resize a
    movie the sound will crackle and pop. Only real solution to this is to get
    better hardware.

  • Max

    the problem is that ventrilo, ts3 and mumble1.1 don't have this problem with
    the same hardware configuration ...

  • Senve

    This is nothing compared to the sound that happens while resizing windows with
    crappy onboard audio chip.

    Don't know about Mumble's sound processing and sound card usage in it, but as
    i said, when i recorded my audio wizard tests, the crackling sound in audio
    wizard was not heard with the raw mic input recording from Audacity. In other
    words the crackling is only in Mumble.

    Even if it was the case that this would be caused by crappy hardware,
    shouldn't this be looked at seriously since I bet vast majority of gamers use
    onboard audio chips nowadays.

    Sample: http://bloodpressure.fi/kuntsi/mumble_crackle.wav

  • Stryke Jones
    Stryke Jones

    The problem is actually with the new CELT codec. Versions before 1.2 didn't
    have this problem. We've found two ways to fix this. Each client can up their
    Quality slider in the compression box, or the server can force everyone to use
    Speex. We chose the latter. You can do this by forcing the server to use a
    lower max bandwidth. 30000 seems to make it use Speex. To do this, edit your
    murmur.ini and change the following line:


    Restart your server, and bingo, no more pops.

  • Senve

    They are there with speex too. At least speex compresses them differently so
    they are not exactly the same, but the crackles are definately still there.

  • Bo Tribun
    Bo Tribun

    Same here, the voice quality is really poor since 1.2.x. We tried any
    suggestion here from the board, no luck. So we revert back to 1.1.8 and
    everthing is fine again. It would be nice to have a serverside option to
    determine which codec / voice quality to use / force.

  • Any solutions to this expect reverting to 1.1.8?

  • Zingan

    So anyone got a solution for this problem? Been struggling myself and while I
    don't have problems like this, or any really, in Ventrilo, is it possible to
    know what's wrong? Why do I get this problem only when using Mumble?

    Why would the sound crackle and so on?


  • Anonymous

    I get this problem also. Lots of crackle and clipping noises, particularly
    from the CELP encoded guys.

    I don't think begging everyone else in the channel to fiddle with their mic
    settings is a good solution.

    I recorded the crackling and shared it with my friends -- they say they don't
    get the crackling on their machines.

    I have a pretty high end system -- DX58SO with Core i7 920.

  • nixon

    Any chance this will be fixed with 1.2.4? Is 1.2.4 still being worked on and
    planned to be released?