Wall Treatments behind frt speakers?

[Parrot_HD]

What is the purpose of wall treatments behind the frt speakers? From what I've been reading, the first reflection point (opposite wall facing speaker) is the #1 focus point for treating a room.

Yet I've seen alot of pictures where there is a treatment behind the frt speakers. I'm in the process of buildinhg treatments for the rear wall in my family room (big reflective wall) and wonder if I should also consider the frt wall with my main speakers.

My speakers are Monitor Audio RS6's and RSLCR center that sit about 12" off the rear wall if it matters.

I'm new to this and have read what I can find but a newb to the concept of room treatments.

 

[Coheednme13]

I've been wondering about this myself

 

[nibhaz]

Assuming monopole speakers: IMO there is very little use of putting a HF or Broad band Absorber behind your mains, because your speaker is not really radiating any energy in those directions until you reach the bass region of frequencies at which time your speaker will begin to radiate in a more omnipolar fashion.

So if you are going to put a panel back there I would suggest something that is at least 4”thick with a 2”air gap, or 6” thick so that you can get some absorption below 80hz.

But hey, I am no expert so perhaps someone will chime in with more knowledge and prove me wrong.

Side note: I have a bunch 703 in the garage that I plan on building into 6in panels for this purpose…as this is the last location I am “allowed” to put panels according to the GF.

 

[sesshin]

They are generally used to flatten out a FR that might be affected by "Speaker Boundary Interface Response"

 

[jostenmeat]

+1 to the above two posters.

Less using measuring equipment, something I personally haven't used yet, it's like with anything else in audio. Experiment!

Get as many as the budget and aesthetics allow, and then play from there.

Yes, I am also under the impression the two most important things are first reflection absorption and corner trapping.

Often, the first places to treat first reflections are the side walls, perhaps ceilings and back wall as second priority. However, the latter really depends on how close you are to the back as well.

You will see that putting in treatments allows you more flexibility of speaker placement. You will also note that changing your listening position will change the priorities of treatment-placements.

Anyways, experiment, and add to taste. Oh, almost forgot, the bang for spot corner trapping is on the front wall. Otherwise, it's virtually impossible to go overkill on corner trapping, and feel free to trap every single corner in the room. However, if you only have a couple/few bass traps, do the front corners.

 

[bpape]

Absolutely correct on the SBIR.

In addition, in a home theater environment, you'd like the front wall entirely dead to prevent sound from the surround channels reflecting off the front wall and contaminating the front soundstage.

Bryan