The next thing you need to do is to draw a line from each viewer directly to the screen, which shows the direction in which each viewer faces. Then draw a line angled 25 degrees to the left of the line you have just drawn from the viewer, for each viewer, until it meets the wall. If the speaker is placed anywhere along that line, then it will be at the correct angle for the appropriate viewer. You need to identify a point along the wall fairly close to the position at which these lines reach the wall. This will usually be somewhere near the middle of the collection of lines. You have then identified the optimum home theater placement for your front left speaker.

You now need to do the same thing, but angle the lines 25 degrees to the right of the direction in which the viewers face. With these lines you can identify the optimum home theater placement for the front right speaker.

Repeat for lines angled 90 degrees to the left, 90 degrees to the right, and 180 degrees (a continuation of the line from viewer to screen, but in reverse). With these lines, you can identify the optimum home theater placement for the surround left speaker, the surround right speaker, and the surround rear speaker.

Ideally, the front left and right speakers should be placed at the same distance from each viewer, as should the surround left and right speakers. This will normally not be possible to achieve, so it should be approximated. Far more important are the speaker placement angles for each viewer, which should ideally not be more than about 15 degrees away from the optimum position. Optimum home theater speaker placement depends on minimizing the angle error for each viewer.

Your subwoofer could be placed theoretically at any point in the room, because the ear cannot easily determine the direction of low-frequency sounds. However, you may find that positioning the subwoofer at different parts of the room change the sounds from the subwoofer; some frequencies may be amplified, while others may be reduced, especially if the subwoofer is placed near a wall or corner of the room. It is suggested that you experiment with the placement of your subwoofer until you find a position that you like.