difussor's

Diffusers on the front wall would still be for "live front".  Diffusers don't deaden sound, they just make it more diffuse (break up the reflection to cause less interference with the direct arriving wave at the listener).  

Front-firing speakers (except for maybe horns) don't radiate only toward the front.  The *desired* wave is only forward, but there is still plenty going toward the sides and to their back, just aim a speaker away from you and see how loud it still sounds!  The higher frequencies are less toward the back, though, and unfortunately the lower frequencies are much less easily diffused (or even absorbed, for that matter) than the highs.

But a dipole speaker (most ESLs, Magnepans, Apogees, Linkwitz, etc) radiate the same toward their back as toward their front.  It is a good idea to deal with the back wave, either break it up with diffusers (if you want to keep the room sound lively) or absorb it (if you're ok with some deadening, or want an easier route than constructing diffusers).

I've been playing with traps and diffusion for over two years and what I discovered about my listening environment surprised me completely.

- Room - 11.5 x 15 x 8ft (tall)
- Hardwood floor with 5 x 8 carpet in the centre
- system is at one end of the room on the short wall
- High wing back chair in listening position at opposite end of the room
- 7ft x 4.5 ft bow window is centred at the opposite end behind listening position
- Wall to the left of the listening position has a double doorway - so no reflected sound
- Wall to the right of the listening position has three seat sofa with high back + float mount pictures - so very little reflected sound
- To the right of the listening position is a 78" tall 14" x 36" book case
- To the left of the listening position is a second wing-back chair
- so there is a fair amount of absorption from furniture/carpet alone

In my case, it turns out there were three areas that caused problems...

- the wall behind the system had an echo, so I made 78" x 15" wide baffles that sit at 45 degrees in each of the corners

- at the wall-ceiling boundary behind the listening position there was significant reflections - I placed an 8ft vinyl roller blind at this point and only needed to unroll it about 12" to kill the unwanted reflections. Unrolling it further resulted in little to no improvement.

- I discovered that there was also significant "acoustic turbulence"  in the space above the book case - a piece of 1" thick foam on the top of the bookcase remedied this.

On my journey I had placed traps in the corners, at wall-floor boundaries, behind the speakers, under the sofa and bookcase.

I've since removed removed all but those that address the three problem areas above and my system has never sounded so good.

Moral of the story - i.e. in my case - less was definitely more

I have since helped a friend with his problems in a totally different room-space - 12 foot ceilings made of concrete, hardwood floor with very little carpet, open plan with kitchen cabinets to the right of the listening area, and again - we found the most annoying issues were resolved by placing traps and vinyl absorption materials at the wall-ceiling boundaries and dealing with reflections above cabinetry.

Turns out the vinyl is a great barrier that absorbs audio wave-forms - turning them into minute amount of heat - and it's cheap

It's not the answer to all the acoustic issues room might have, but with a little investigation it can sure eliminate a lot of those real ugly traps that have been known to "invade ones listening space".

Hope that helps 

I also have a very small room. I found it's essential to use absorber to deal with early reflection (place them in direct reflection points). Diffuser will also help in establishing good soundstage.

thanks everyone for your input...appreciated