Disable the Sudden Motion Sensor to avoid the harddrive heads parking them due to loud noise in a club.
To check if Sudden Motion Sensor is activated, use the following command and look for the sms setting (1 = enabled) :
# sudo pmset -g
To disable Sudden Motion Sensor, use the following command :
# sudo pmset -a sms 0
To enable Sudden Motion Sensor, use the following command :
# sudo pmset -a sms 1
From http://rc.vc/files/traktor/optimizing_macbook_for_traktor.txt
Hope this helps!