Don't know where this equilateral triangle deal came from but it is erroneous.
Speaker setup is a two-step process.
Step one, move them around relative to the walls listening for bass balance and tone. Listener position matters as much as speaker location so listen to each speaker location from closer and further away. Step One the speakers do not need to be perfectly equidistant or symmetrical, but pretty close.
Step Two, now from the smoothest sounding location measure very accurately to get them perfectly equidistant and symmetrical. Listen for image focus and sound stage width and depth. Adjust the toe in very slightly and the image focus and depth will be greater. Adjust the toe out very slightly and the sound stage width will expand. Equidistance and symmetry must be precise each and every time or you will lose image focus and think it was due to changing toe when really it was sloppy symmetry.
When you are happy with the balance you are done. Does not matter what the distances are. That is all simplified to the point of rubbish. This is how you do it.
Speaker setup is a two-step process.
Step one, move them around relative to the walls listening for bass balance and tone. Listener position matters as much as speaker location so listen to each speaker location from closer and further away. Step One the speakers do not need to be perfectly equidistant or symmetrical, but pretty close.
Step Two, now from the smoothest sounding location measure very accurately to get them perfectly equidistant and symmetrical. Listen for image focus and sound stage width and depth. Adjust the toe in very slightly and the image focus and depth will be greater. Adjust the toe out very slightly and the sound stage width will expand. Equidistance and symmetry must be precise each and every time or you will lose image focus and think it was due to changing toe when really it was sloppy symmetry.
When you are happy with the balance you are done. Does not matter what the distances are. That is all simplified to the point of rubbish. This is how you do it.