No audio from safari or firefox

I'll take a wild guess. A problem with the plug-ins that run the movies in your browser. I'm not an expert here, but it seems several 3rd party video/audio plugins are often called upon, as well as Quicktime. However, control of the plugins is not made easy, and I don't know details. I would check the Preferences of the browsers such as Safari/Preferences/Security to make sure Java and Plugins are checked. I'm guessing a reinstall of some media players like Flipformac might be needed - I think they install plugins for the browsers.

Strangely enough this solution did work for me too. Both YouPorn and PornoTube (and MySpace and YouTube) didn't produce any sound in Safari nor Firefox, iTunes and the plopping volume buttons did work fine. Restarted Safari/Firefox to no avail but after googling came upon this discusion and this trick did work.

Why? How? Don't know but there has been a power failure just some minutes ago so my iMac might be a bit confused.

This problem is not limited to the PowerBook G4 (15-inch Aluminum).

I was having the same problem, did a little more digging and found this:

Video but No Sound on YouTube, MySpace and Flash Video on Mac OS X inside Safari or Firefox:

When watching web pages with embedded Flash video or animation such as movie or video clip on YouTube and MySpace using Mac OS X, users may hear no sound. The no sound audio output problem happens despite video playback is fine, and the issue can happen on any web browser, i.e. Safari and Mozilla Firefox. Strange thing is that, when using other applications such as RealPlayer, QuickTime Player and VLC Player, the sound is played properly. And no audio output issue does not affect embedded QuickTime including HD contents on the web.

Apple Mac OS X support site explains that the no audio from certain multimedia content issue is caused by some audio applications that change the computer’s audio settings to a sample rate that is too high for other applications to use. The notorious programs include certain versions of Real Player, VLC Player and Audacity.

The solution to solve the Internet movie no sound or audio output is to reset the audio setting in Mac OS X to original configuration:

1. Open “Audio MIDI Setup” (/Applications/Utilities/), then check the “Audio Output” setting.
2. Change the “Audio Output” setting to 44100.0 Hz.
3. Quit Audio MIDI Setup.

If the Audio Output setting is grayed out or disabled, go to “Properties For” tab in Audio MIDI Setup, and select “Built in Output”.

I have exactly the same problem. Any help? Thanks

Your fix worked, RoryCJ -- thanks very much! And thanks for the explanation/solution, LastGerm -- I had indeed opened Audacity just before this happened.

In case anyone was curious, this fix STILL works, 3 years later!