I know this is a little of the ‘Macintosh’ topic but I thought I’d post it anyway.
Enter the number: *#8999*8378#
This will put your Samsung D900i into test mode and give you a new menu where you can change all the audio settings for the phone, all the gains (eg microphone, speaker) in various modes (eg handsfree, carkit etc). Make sure you take a note of the settings before you change anything so you can change it back.
The following abbreviations mean:
– Loud Speaker SUP : slide up
– Loud Speaker SDN : slide down
And the others are various versions of handsfree etc. post a note if you work them out.