You can make HDD inside MyBook Live drive work even more quiet by changing AAM value.
It is perfectly safe to do that. You will loose maybe just 1% of drives speed performance by doing that.
To change value use following command from root account:
hdparm -M128 /dev/sda
After that you can execute:
hdparm -I /dev/sda
and it will shows tons of info about your drive.
You should see following text somwhere - Recommended acoustic management value: 128, current value: 128
That means you set it correctly.