Sub placed behind couch?

[Sir Terrence]

Originally Posted by sterryo

from Hsu Research website

What is the best place to put a subwoofer?
Due to certain principles of acoustics, the corner of the room is almost always the ideal location to place a subwoofer. The next best location to place a subwoofer is along a wall. Home theater aficionados may like to place the subwoofer to the side or behind the seating, near the listener, as this will provide better upper-bass impact. For the best experience, avoid placing the subwoofer or your seating in the middle of the room, because there is a bass void there.

No matter how many times you tell folks this, people are going to do what they want to do. I always get told "its sounds great there"(by the side of the couch). Its great until I pull out my RTA and began to measure huge dips and peaks in the response in multiple position within the room.

Our ear/brain mechanism has this tremendous ability to ignore problems if we believe something is satisfactory. Our ear/brain mechanism has a tough time hearing problems in the deep bass, and accessing how bad they are. Our hearing is just too insensitive in that area. Most folks just calibrate the amplitude of the subs in relation to the mains. In this case you are aligning your room modes to the mains, not the output from the sub itself. If you want to get the ulitmate performance from your sub(and hear what it really sounds like) you must do a frequency sweep first, equalize out the room modes(nodes can be ignored, they are inaudible), and then calibrate the subs to the mains. That way any room modes are reduced in amplitude, and a more accurate calibration to the mains can be acheived.