Recently, most Samsung Galaxy S2 users who are already upgraded to the latest Android 4.0.3 Ice Cream Sandwich (ICS) talking about the problem of a wakelocks as caused by the Audioout_1. This has been noticed by using Better Battery Stats on the new ICS firmware with the Galaxy Nexus, causing the battery draining fast, while when listening Audio like Google Music, the Sirius/XM app or perhaps just happens when doing nothing at all. So, if you'll also newly upgraded your Galaxy S2 to the newest Ice Cream Sandwich firmware and experience this kind of issues too, this might help you to solve that problem. This reportedly occured on firmware with build number I9100XWLP2, I9100XXLPQ and I9100XXLP7, other carrier branded version like T-Mobile and Vodafone with firmware build I9100BOLPD and I9100BULPC and on later version were not already been tested.
According to some users experience that the AudioOut_1 Partial Wakelock appears to be connected to the Touch Sounds and Screen Lock Sounds options in the phone's Sound Settings. So, to disable or shutting down the Touch Sounds & Screen Lock Sounds in Settings will fix the the battery draining problem.
What is AudioOut_1 basically?
"AudioOut_1" is a Wakelock that is basically a kernel process that funnels data from audio apps to the audio hardware. It's what processes audio from say, Pandora or Slacker Radio, and passes it to the phone's audio hardware. (from toms-world.org)
Here's how to fix the AudioOut_1 Partial Wakelock problem:
Go to > Settings > Sound
Uncheck this options:
"Screen lock sound"
I just left the "Ring and Screen Tap" vibra option" on mine.
I tried it and it happens that my Galaxy S2 went in an hour losing only 1% of the battery and the results the WakeLock percentage for AudioOut_1 goes down as I check back into BetterBatteryStats. Unlike before that I have about 10%-15% battery drain even when my Galaxy S2 is on idle mode. So, just try it out. Enjoy!