Speakers room positioning - diff tricks ?

Dear All, with Tube traps analyst suggestion, my speakers ended up positioned with 1/3 on their back with the listening position 1/3 from the back wall.

Wondering when this is the best trick to position speakers or shouldn't be just one of the many. For example I recently read the Cardas white papers and it seems to me that the speakers will ended up about 1/4 from their back wall and the couch 1/2 in the room, much different from Tube traps advises.

To wrap-up which one of the following is the most used ?
1- Tube traps room study
2- The speaker manufacturer manual advise
3- Just your ears ?

Tks for commenting. Soon my Avalon will arrive !
Generally speaking I think these are all starting points,and great ideas. All rooms are a little different,along with personal tastes being different. I think any on of them can be used with great success ,but the final tweek must come with the trial and error . good luck
I am a believer of the one-third, one-third rule as a guideline. The listener should also be seated away from the speakers the approximate difference separating the speakers plus 5 to 10%. As the previous post stated, these are starting points as each room is different. Tube traps, accoustic wall panels, diffusors, etc. are all used to make up room dificiencies. An example is a point many overlook is the floor of the listening room. If concrete is under the carpet, tube traps are rarely needed if the room has adequate volume.
Currently on Audioasylum there is a thread on this subject (room reinforcement)to which David Aiken contributes to a discussion of bass frequencies - his summary is that to position speakers at 1/3 and listening position at 1/3 will tend to help on the null side and at 1/4 and 1/4 will help on the reinforcement side. This has been my experience. This is a thread well worth reading and i highly recommend it.
Tks anybody.
Cannot trace the thread you mentioned at AA. Would you pls post the link ?
Look under General Asylum for "room acoustics" posted 1/29/03 by amos ( and responded to by David Aiken on 1/30/03 ( Good luck.
I tend to use an odd even line grid to get me going, not always thirds or fourths but odd/even. Then I go from there and depending on room size and speaker size (how much air they can move) I'll work from there as to back/side walls. It gets me started but I still spend a lot of time listening by ear to get just right.
I didn't look for the thread that Newbee mentioned, but this sounds a lot like the Audio Physic method of speaker placement. You might try their website to see if they still have this approach available for viewing. Sean