Created attachment 8532037 [details] file included for easier debugging, same as http://jsfiddle.net/nvkow6r8/6 User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:33.0) Gecko/20100101 Firefox/33.0 Build ID: 20141113143407 Steps to reproduce: Open http://jsfiddle.net/nvkow6r8/6/ and click on "Run" (top). Then click on the volume slider, first on the left side, then on the right side. Actual results: If you click on the left part of the slider, the volume is going to 0 in 1 second, as expected. But If you then click on the right, the volume is jumping to 1. Expected results: The audio gain should go to the value in 1 second, like in Chrome, and Safari. I tried with Firefox 33, and 35. It seems that the value oceanGain.gain.value, which is used to set the beginning of the ramp, is never updated. As a side problem, the debugger freezes Firefox for a while when there is a breakpoint within the function changeVolume, but it will resume (and stop sound) eventually. It is the same without any breakpoint, oceanGain.gain.value is always the initial value.
Attachment does not work on-line. I do not know why.
Thank you for moving the bug to the correct section... Now I see that it might be a duplicate of Bug #893020
Fixed by bug 1106649.
There is no OscillatorNode here, so I suspect comment 3 was accidentally made on the wrong bug.
Woops yes, this is a correct dupe though.