Axiom Home Page Forums General Discussion The Water Cooler Speaker Setup?

Speaker Setup—Step 2. Laying out the Room

There is an easy way to get the best out of your room that is predictable and repeatable for many rooms. This will allow you to plan for furniture, seating areas, and speaker positioning ahead of doing anything. How do I do it? Like this. I would visit the house of a client before hand and measure the room and go home and draft it out in advance. I would have a road map on site to make the install quick and simple. The clients were always impressed, and I was always finished in as efficient of fashion as possible. I use Sweethome 3D to draft spaces. It is fast and free. The learning curve is low.

1. Choose to lay your room out in the length orientation. Doing this will result in more options for listener placement as well as more room possible behind the speakers in most residential rooms. Orienting your room along the long axis will result in a lower first order room mode that is sympathetic to your woofer’s movement. We already know you are likely to sit on the centerline of the room (a smart idea) so we aren’t really worried about the width mode, as we are in a null by default. The width null will be handled with symmetrical loudspeaker placement within the room. 2 Loudspeakers equidistant from a center point playing a mono mixed bassline as in most songs act as a single phantom source at the center null point, thus cancelling it. No biggie. Same idea is found in subwoofer placement.
See: https://www.harman.com/audio-innovations

2. Choose to place the listener on the centerline of the width of the room at a room interval of 0.2x,0.32x,0.45x ,0.55x, 0.68x, 0.8x the room’s length. (Anthony Grimani.) So, for a room a given length of 223” this results in the listener being placed at optional positions of 100” or 122” or 152” or 178” from the front wall. These ratios along the room’s dimensions are considered “neutral” when compared to other positions along each dimension axis. See image from pg. 304 Handbook of Sound Studio Construction showing Null points of first and second order room modes within a common sized room.


3. Choose to place your loudspeakers using set ratios. Distances from the front wall corresponding to a ratio of 0.2x or 0.32x from above. So for the example room of 223” the options are 44” or 71” from the front wall to front baffle of the speaker. Again, these positions are most favourable to allow a “neutral” presentation from your loudspeakers along the length axis of the room.

4. Choose to abandon an equilateral triangle. Place your loudspeakers at a distance of 0.85x or so from each other vs the listener to them. An isosceles (not equilateral) triangle is the best choice for a 2 Channel system. Placing your loudspeakers in an equilateral triangle is likely to result in a very wide soundstage at the expense of weight in the phantom image. It will also very likely result in a phantom accompanied by 2 hard panned channels of sound, rather than a continuous wall of sound where the phantom, speakers, and in between have equal weight and the speakers are not apparent to be sound sources.