Yesterday we learned that our rooms are a necessary element in the stereo system. It’s good to think of your room as but another component in the chain of your music system and with that thought in mind, we can get comfortable with the idea of working with our rooms rather than working against our rooms.
Our rooms are not the enemies they are made out to be. In fact, let’s consider our room as our new best friend and get to know her. I am using the female gender to describe our new friend because our room is the wellspring from which the life and vitality of our music system is going to blossom and thrive.
Understanding that the primary contribution of our room is her ability to reflect sound back to our listening chair helps us appreciate the need to maximize good reflections and minimize bad reflections. We need both and getting these reflections right is the key to a great sounding music system.
Room reflections happen from any surface in the room but the primary source is the sidewalls. This is because our floors are typically carpeted, our ceilings and rear walls far away, and our sidewalls closest to our loudspeakers and their reflections pointing right at our ears.
So let’s start roughing in our loudspeaker position with all this in mind. Using our Rule of thirds we will place the loudspeaker pair approximately 1/3 the length of the room away from the rear wall. In an 18 foot long room that means we’d place the pair 6 feet from the wall behind the loudspeakers and 12 feet from the wall behind the listening position. The listening position is, of course, 1/3 the total length of the room from the wall behind the listener. Note: if this is too far out into the room for your tastes or your family’s needs, use the sidewall boundary method below to determine the minimum distance you can place the pair from the rear wall. Just stand against the wall behind each loudspeaker and repeat the same process described below.
Place the two loudspeakers fairly close together – perhaps even just a couple of feet apart from each other, giving more than ample space between the outer edge of each loudspeaker and the side wall.
Now, here comes the cool part – the part where we get to know our new friend the room. Walk over to the sidewall adjacent to one of the speakers and face the wall behind the listener. If you’ve started with the right loudspeaker, this would mean your left shoulder is touching the sidewall and your right shoulder is pointing towards the right loudspeaker. Now, start to talk and listen to the quality of your voice – it’s more than likely affected by the sidewall. What you’ll hear are two things: a reinforcement of the lower octaves of your voice because the sidewall is acting like an acoustic “amplifier”, and a reverberation or slight echo. If you keep talking and sidestep away from the sidewall and towards the right loudspeaker, this “boominess” and reverb in your voice will decrease until it sounds like your normal voice, unaffected by the sidewall. Mark that spot with a bit of tape and then repeat the process on the other side. Typical distances can range from a couple of feet to three to four.
Next, measure the distance you’ve determined is the point your voice is least affected – average the two distances – and place a new piece of tape exactly the same distance for each side. For example, let’s imagine on the right side you found that 3 feet was perfect and on the left side you found that 4 feet was right – measure out 3.5 feet from each of the sidewalls and place your tape mark there.
Now, move your loudspeakers so the outer edge of each loudspeaker touches the tape mark at 3.5 feet. This is a great starting space and here’s the deal: don’t ever go over this mark if you can avoid it. When we learn how to adjust the distance between the two loudspeakers it’s fine to increase this distance from the sidewall, but we’ll try like heck to never violate this space.
Make sure that your loudspeaker pair are now perpendicular to the wall behind your listening area with no toe in at all.
Paul McGowan – PS Audio, Inc.