Comment 6 for bug 527866

I have debugged this with Lennart today at the boston summit, and we have pinpointed the problem: alsa/udev is overriding pulseaudio.

This file in particular: /lib/udev/alsa-utils

Whose contents are:

#!/bin/sh -e
# udev script for alsa-utils
(
        DEV_BASENAME="${DEVNAME##*/}"
        N="${DEV_BASENAME#controlC}"
        exec /sbin/alsa-utils start $N
) &

...If we disable that file by replacing the contents by:

exit 0;

It works. The microphone's sound level is remembered no matter how fast/how many times you unplug/replug.

This is an Ubuntu-specific bug.