The nice thing about a rectangular room is its acoustic predictability because of its
shape. Divide your room into thirds. Place your speakers on the line that divides the
first third from the second third. This will be your speaker set up start point. Make sure
your side walls are equal distance from the left and right channel speakers. Move both
speakers back and forth together along that axis line. Move in small increments, usually
1". Perform the exercise right to left.
Your first concern is finding the
correct speaker/room position that produces the best frequency response curve for the room
and listening position. Focus on the low frequencies first. You can deal with middle and
high frequency issues later. Find the speaker/listening position that gives you the least
low frequency pressure issues and then go after those with a passion.
foam over your window will not stop sound from leaving the room. You need sound isolation
technology to increase sound transmission loss. If your window sits in a cavity, such as a
bay window, fill the bay in with your foam and install another wall over your window. Make
sure you leave at least a 3" air space between your new wall and existing window. You
don't need to use the window because you have music.
low frequency absorption solutions. Listen to the music without hearing the room!