acoustic treatment placement

[yoga]

If you do not have enough acoustic panels to cover the walls what are your best positions if the traps you have made is only 1200 tall and wide. Is it better to cover center of your panels at ear level(diagram 1.1), like where your ears are at, at the mixing position, is that were most of the bad waves that will hit your ears will be at, at ear level.
_______ ceiling

]
] @(o-o)@
]

_______ floor

diagram 1.1

definition

]
]
] = acoustic panels

@(o-o)@ = person


Is it ok if I just leave it on the floor so I don't have to make stands for it. It's still at ear level, but just (diagram 1.2).

_______ ceiling

] @(o-o)@
]
]_______ floor

diagram 1.2

How important is it to have front absorption. I read somewhere, can't remember exactly where, that front absorption is not necessary. Ive seen people put diffusers at the front of the mix position. How important is it, will it affect the room so much if there isnt.

If you have a room of 4X6meters, like

front
[.]
[ ]
back

. = mix position

In order of importance, what sections would need what absorption and how important in ranking is it. example.

1- front corner bass traps, 80-240hz
2- back corner bass traps, 80-240hz
3- back deep bass traps 40-100hz
4- front sides first reflection mid bass traps, 100-240hz
5- back sides first reflection mid bass traps, 100-240hz
6- front diffusers

Also I have some acoustic foam tiles. Where should I spread those.
I am trying to figure out where I should put what and what else I need to make to cover the general acoustic stuff for a room of that size. Please, I am after what the general rule is or what most people have done that gave them good results.

[knightfly]

The middle 1/3 (height-wise) or ear height, is definitely the most important - more if you can.

http://www.johnlsayers.com/HR/index1.htm

shows room placement and types of absorbers typically used.

Front absorption (behind speakers) can help smooth out the frequency response by minimising boundary interference - typically 3-4" of rockwool type stuff placed a few inches away from the wall, large enough to be seen to either side of each speaker by at least a foot or so... Steve