In recent builds (now 2903) Sip Communicator has some issues with PulseAudio - If i start a call everything is fine, i have ~20% CPU usage and the call works.
But after i finish the call Sip Communicator still consumes the same amount of CPU time and pavucontrol shows 1 recording and 1 playback stream.
Making another call adds 2 more streams that remain open after the calls finish and so on for each call. But the sound quality deteriorates after the second call, there is a loud buzzing noise sometimes that appears together with the streams in pulseaudio start to flicker. After 2-3 calls the java process starts to consume 100%+ CPU (Athlon II @3 GHz) and eventually becomes unresponsive.
I use Debian Squeeze 32-bit.