A have a laptop (Acer) with two front speakers and subwoffer (Acer Tuba). After upgrading to 12.04 only front speakers are working, no sound from subwoffer. There is no 2.1 configuration on Sound configuration panel, only 2.0 4.0, 4.1, 5.0, 5.1, but no matter what I choose a can't get sound from subwoofer. Sound is very poor quality without bass speaker. Sound card is Realtek ALC888.