Ok I have read many past posts about the setting of speakers with the spl meters but could not work out what was the best way of setting up the system. Firstly I was wondering if I use the test tones on my amp (sony 475) do I set the sub the same as the speakers e.g 75db. I read that the spl meters are not that good at low levels, and I saw that there are some adjustments you can make. In the FAQ it says to set sub at 85db has an adjustment already been made for this etc. Secondly is it better to use THX optimizer and what setting should I use e.g. does it adjust for the sub aswell. A simple answer must be available.