Comment 41 for bug 29760

Adobe has published the reference code to write audio plugins for flash 9
http://labs.adobe.com/wiki/index.php/Flash_Player:Additional_Interface_Support_for_Linux
Revolution Linux, a french provider, has written one that supports OSS ALSA ESD and Pulseaudio (http://pulseaudio.revolutionlinux.com/PulseAudio) it solves most if not all problems related to audio in Flash. I compiled myself the last release but there are .deb for a little bit older version available here http://pulseaudio.vdbonline.net/libflashsupport/