I believe the former editor of TAS likes to take credit for identifying this concept but I think it has been known for some time, he was just the first one to publicize it. Other odd dimension fractions have been recommended as well - 1/5, 1/7, etc. Since another basic rule of acoustics is to avoid square rooms (equal dimensions maximize room nodes), assuming the room length and width are different, applying a fractional multiplier like 1/3 will result in different distances from the front and side walls which should also provide a benefit.
As Newbee points out, you should be just as concerned with your listening seat placement as with your speaker placement.
As Newbee points out, you should be just as concerned with your listening seat placement as with your speaker placement.