How to disable sound in Firefox?

One of the more common questions I receive to my answerblog is How do you disable (background) sound in Firefox, a question I have always been tempted to answer with “By installing Opera, where you can turn embedded sound on and off whenever you feel like it”.
However, there is an answer: “Adblock”: can block files by type. Add the following to your Adblock:
* == *.mp2* ==
* == *.mp3* ==
* == *.mid* ==
* == *.wma* ==
The answer to this was found in the “LiveJournal Mozilla Community”:

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  1. Too bad it doesn’t work for sound in Flash apps. I don’t want to disable Flash completely, but it seems like most offenders are Flash apps. Either way – thanks for sharing this tip!

  2. Captain Kirk

     /  2005-06-09

    this isn’t really a solution. if you do this, adblock will block anything with the string ‘mid’ in it, like or searching google for the woord ‘mid’, etc…

  3. CaptainKirk

     /  2005-06-09

    this is how you block background sounds:
    put this in your userContent.css file:
    /* block embedded sounds */
    embed[src*=”.mid”] { display: none !important }
    embed[src*=”.mp2″] { display: none !important }
    embed[src*=”.mp3″] { display: none !important }
    embed[src*=”.mp4″] { display: none !important }
    embed[src*=”.wav”] { display: none !important }
    embed[src*=”.wma”] { display: none !important }
    this will block anything in an embed tag with .mid … in it. unlike adblock, you can still search for mid on google 🙂 and download mp3’s from a direct link, etc. you can also use this to block embedded mov, mpg, etc.
    (on windows, you can find that here: C:\Documents and Settings\Administrator\Application Data\Mozilla\Firefox\Profiles\xxxxxx.default\chrome\userContent.css)
    (you have to create that file, it won’t be there if you haven’t already)

  4. Gene

     /  2005-09-14

    Here’s how to kill sound from flash. A couple of sites pissed me off with obnoxious sounds to find this.
    1. Shut down mozilla/firefox and find “” in your plugins dir.
    2. Edit this with a binary editor, something like “hexlify-find-file” in EMACS.
    3. Look for the string “/dev/dsp” and change it to “/xxx/xxx” – now it can’t open the sound device.
    4. Save!
    Now you can restart your browser and be free of irritating flash noises.

  5. CaptainKirk

     /  2005-11-09

    /* block embedded sounds */
    object[data*=”.mid”],embed[src*=”.mid”] { display: none !important; }
    object[data*=”.mp2″],embed[src*=”.mp2″] { display: none !important; }
    object[data*=”.mp3″],embed[src*=”.mp3″] { display: none !important; }
    object[data*=”.mp4″],embed[src*=”.mp4″] { display: none !important; }
    object[data*=”.wav”],embed[src*=”.wav”] { display: none !important; }
    object[data*=”.wma”],embed[src*=”.wma”] { display: none !important; }

  6. The way I like to deal with this is not to make accessing media impossible but to make it voluntary.
    I find the major offender nowadays is the autoplaying of embedded Flash. So I use flashblock, which interrupts Flash elements—whether they are noisy ads or useful aids—with what amounts to a push-to-play button. You may still see and hear them if you wish (for instance, after turning down the system volume) but you are no longer ambushed by Flash when loading a page.

  7. For what it’s worth: The Opera equivalent to the Flashblock extension can be found as a “User Javascript”:
    As for just muting sound, I’d recommend looking at “FlashMute 2”:

  8. plizzzzzz

     /  2006-02-01

    Very usefull tricks. But i like to disable sounds of firefox in general like ugly klik in Find toolbar, when it cannot find string on page.
    I always thought it is disabled by control panel sounds-nosounds setting.

  9. What about a way to block sound in Firefox that you can turn on and off easily? It would be cool if every tab would load with all sound disabled, but if the page had a video clip or something, I could right click the tab and enable sound for just that tab. That way I could listen to my music and watch embedded clips.
    Is there anyway to do this?