Symmetry is the goal when setting up a speaker system, but as one would expect, there are very few listening rooms that are perfectly symmetrical. Some people promote the “Golden Rule” method (.6 : 1 : 1.6), but that method almost never works because of room geometry or things in the way of achieving the correct spacings. Speakers and listener end up forming a triangle in the listening room. The triangle needs to be symmetrical along a line from the listener to the exact center between the speakers. I have found that almost all speakers need to be pointed at the listener’s position.
There are some general rules that I follow (but not always). One is keeping the speakers away from the side walls. That first reflection adds a time delay and smears the direct radiation from the driver(s), so the side reflections need to be absorbed, eliminated, diffracted or altered in some way to keep its intensity from the listener. Next is dealing with the “tweeter at ear level” rule. I generally don’t like it. HF tend to beam and that is not where most of the musical content is anyway, so why point it at year ears. Most musical content is in the midrange and upper bass, so if I were to put any drivers at ear level, it would be one of those drivers. The tweeter is the “icing” on the cake, not the cake. So, my speaker elevation is higher than the normal. Live concerts have the orchestra on a stage, the rock band is on a stage, the instruments or sound reinforcement is on the stage or elevated even higher than the stage. Listening room furniture is out of the way when speakers are elevated and hardwood or hard surface floors have less effect on primary reflections. No bookshelf speaker should be on the floor and some floor standers shouldn’t be either. Don’t set bookshelf speakers on their sides, unless they were design for such a position.
I find that I favor the long front wall to set my speakers, as it allows for a wider spacing between the speakers. This produces a better “stereo” effect and better defines the imaging and positions. It also seems to add a bit of depth to the soundstage. So, two to three feet seems to be a good number to start at, perhaps the same distance from the front wall. Now there are basically 3 spots for the listening position, one is near field, the other I’ll just call a normal position (around 8 feet from the speakers) and the third is a distant position. In almost every case, the toe-in angle matches the vector line of the speaker to listener position. In other words, when seated at the listening position, you are looking at the speaker’s face straight on. This is at least a starting point. I do have some speakers that benefit from lesser angles, but I always start from this position. I also like to pick an aiming point that is somewhat behind my actual position, perhaps by a foot or two.
I find that subwoofers benefit from being close to one front wall corner. Corners can act like amplifiers as each surface can have increased gain. There are plenty of opinions on this placement topic, so the golden rule is to experiment. If 2 (or more) subs are operating, they need to be symmetrically located within the geometry of the mains and listener position.
To sum it all up, I use a tape measure to measure corners of speakers to surfaces, from speakers to listener as all (as noted) need to end up symmetrical. The fun part is that my spouse likes music too, so we have to have a sweet spot that is built for two. We both get great stereo imaging using this alignment method. As a side note, I must admit that there is always the occasional tweaking going on, changing the toe-in angle is the usual tweak. But both get tweaked to the same amount to keep the symmetry. I also find that some speakers eventually bounce out of alignment and need to be checked from time to time. I have developed a map that has dimension that describe the speaker’s position. Sounds extreme, but has come in handy several time. If a nice set-up has been achieved, map it!
