The ultimate would be a LEDE with the correct amount of Bass control.
The concept behind LEDE is that close and direct (first) reflections of sounds from the speaker are the "most" damaging to the sound. So all these refelctions are addressed by treating the sections of the room closest to the speakers.
Also since most don't listen in the "extreme" nearfield, then the ear/brain needs some "air" (which is allowed in the Live End) to provide a sense of "space".
If you were in an Anechoic Chamber and didn't sit in the extreme nearfield, then the lack of sound (air) around you would be distracting. For multichannel listening this may not be the case.
In all this discussion we seem to focus on the reflections off the flat wall surfaces, and the Bass problems, but there are other areas too.
All room corners are "sonic garbage collectors and regenerators". As the sound wave is guided by the walls, ceiling, and floor to "collide" in the corners, and then spit out back into the room to destroy your program.
So after addressing:
1) The front wall
2) All first reflections (side ceiling and floor)
3) Bass problems
It is best to look into controlling the corners. To do this look at the products offered by Eighth Nerve, Room Tunes and others. Many of these too can be DIY projects.
The idea is to reduce/block the mids and highs that go into the corners and then keep them from reflecting back out. This can be accomplised to a great degree by creative application of acoustic foam.
Bass on the other hand is larger and stronger and the idea is to reduce its power going in, absorb its energy, and neutralize its reflected wave coming back out.
This too can be done by using foam, but as Dan suggests a more aggressive and effective method is placing a stronger sound dam such as a bass panel (could be a fiberglass panel) in the corner so that it creates a "trap" so that the wave can enter but has a more difficult time escaping, back into the room.
After putting an acoustic foam panel in the corner, simply place the fiberglass panel so that it forms a triangle with the two walls that form the corner. This panel can be touching the walls, or it can be slightly out (allowing the bass wave entry to the corner)
The wave enters the corner by traveling along both walls. The energy meets and is strongest in the very corner (just stand directly in a corner sometime while playing deep bass and see what I mean).
The colliding bass is then push/reflected straight out of the corner back into the room. That is why ASC bass traps (the round upright cylinders) are placed at the intersecting line coming out of a corner.
Actually large soft furniture (like OS Chairs) placed in a corner can also go a long way in helping with this task.
The other area of a LEDE room (the Live end) is not meant to be "reflective", but dispersive for best result. You really don't want all your sound bouncing around in big "chunks", you want the maximum dispersion of that sound, so you still have "air" but not mass reflection of the program material.
To that end make the walls and area of the LE, busy with lots of angles, and uneven reflective surfaces.
Anyhow just a few more thoughts on "THE ROOM"
