With all due deference to SirQuack, the advice on the first reflection zones is wrong, based on bogus information often intended for studio control rooms.
I have a question for you on that Alan. It is my understanding that reflected sound that arrives at less than 10ms. after the direct sound actually negatively affects the soundstage, collapsing it. This is supposed to be an issue in very small rooms. Do you disagree with this as well?
It seems to me that there is no 'one rule' that applies in all situation and that you need to take a look at the specifics of size construction materials and furniture in each room to decide how to tackle room response issues.
