I can confirm that this bug occurs on Inspiron 700m with alpha 3 install - Salavan's fix https://bugs.launchpad.net/ubuntu/+source/alsa-driver/+bug/242966/comments/2 did not work but step 1 (only) of http://ubuntuforums.org/showthread.php?t=866965 did cure the problem after reboot.
I can confirm that this bug occurs on Inspiron 700m with alpha 3 install - Salavan's fix https:/ /bugs.launchpad .net/ubuntu/ +source/ alsa-driver/ +bug/242966/ comments/ 2 did not work but step 1 (only) of http:// ubuntuforums. org/showthread. php?t=866965 did cure the problem after reboot.