Opinions on placement of these diffusors

[robc1976]

Wanted some opinion on this, I recently treated my room (Nothing high grade, but it sounds great). I have seen posts of people putting diffusors behind there mains, and some do not suggest it...below are pics of my room and my proposed locations for the diffusors...any suggestions? I have 9.1 A-DSX if that helps. Auralex reccomended I put the diffusors over the absorbtion for better broadband control and most are saying that is odd because the sound would have to go thru it and I agree. Would it be better over MLP to take the absorbtion out or maybe cut the foam out from under the diffusor and basically have the diffusor fit in and have a bit of absorbtion on the sides wich would make a pretty good design LOL!! The back wall seems to be fine because the diffusors are hardly covering the absorbtion. And on "the right side of MLP pic" you will see my surround speaker and I am considering taking (1) absorbtion panel out of this area.


Front soundstage:

Right side of MLP:

Left side of MLP:

Above MLP: (This pic is just what I already have and want to add.)

Back-wall:

 

[agarwalro]

The side speaker placement appears to be incorrect. IMO, this needs to be corrected before anything else. From the THX website,

THX 7.1 placement:

Dolby TrueHD and DTS MA placement:

Notice that in both cases the side speakers are slightly behind the point representing the main listening position while you setup seems to have them ahead!!!

NOTE: Goes without saying, once the speakers have been rearranged, any previous calibration is defunct. So, rerun auto setup and tweak all parameters again.

The question on placement of diffusers is a really good one and my instinct tells me, this is a very difficult to answer with a simple yes/no. Unless your room sounds dead, you should not need diffusers. Adding a carefully balanced mix of absorbers and diffusers will give you the biggest sound stage, best imaging and flattest FR. I suggest, put them in the locations you indicated and do objective (FR plots) and subjective (changes in imaging and sound stage) evaluations. Typically I have seen,

Absorbers – Room corners and wall intersections (for Bass Traps) and First Reflection points for mains (typically for point immediately behind front speakers and point on side wall in direction of main listening position)
Diffusers – Ceiling (between main listening position and line connecting main speakers) and First Reflection points

 

[robc1976]

The side speaker placement appears to be incorrect. IMO, this needs to be corrected before anything else.
Notice that in both cases the side speakers are slightly behind the point representing the main listening position while you setup seems to have them ahead!!!

You must be looking at it wrong ( I have 9.1) because my surrounds are 5ft behind MLP and 2ft above the listeners head in back of MLP at 110 degrees? You may be seeing my wides (my front sound stage has 4 floorstanding (FR & FL and Left wide and right wide and right height and Left height)...I am running audyssey DSX with the fronts are at 30 degrees, heights at 45 degrees and wides (wich I believe you are referring to) are at 60 degrees. My surrounds in the first pic are not shown becasue my lens doesnt go wide enough...I can see how that would confuse someone.

 

[agarwalro]

I am running audyssey DSX with the fronts are at 30 degrees, heights at 45 degrees and wides (wich I believe you are referring to) are at 60 degrees. My surrounds in the first pic are not shown becasue my lens doesnt go wide enough...I can see how that would confuse someone.

I stand corrected and am intrigued. Reading on DSX now. C

Would you have any personal impressions regarding comparison with the more conventional 7.1 speaker configurations and DSX? Thanks!

 

[robc1976]

I stand corrected and am intrigued. Reading on DSX now. C

Would you have any personal impressions regarding comparison with the more conventional 7.1 speaker configurations and DSX? Thanks!

There is no comparison....in a traditional 7.1 it uses S.back and ONLY 7.1 content will engage these, plus the placement is terrible. In A-Dsx all 5.1 content is played in 5.1, 7.1, 9.1 or 11.1. Out also widens and heightens the sound stage. It is a 3 dimensional sound.

 

[lsiberian]

Way too much diffusing for my taste. The only place for diffusing in a home theater is back corners in the surround. Everything else except the first reflection points should be bass trapped IMO. But hey if you like it than who am I to argue. I can't even put up treatments in my theater room(WAF)

 

[robc1976]

Way too much diffusing for my taste. The only place for diffusing in a home theater is back corners in the surround. Everything else except the first reflection points should be bass trapped IMO. But hey if you like it than who am I to argue. I can't even put up treatments in my theater room(WAF)

Usualy most 1st reflection points are absorbed (Ceiling, walls) I do have bass traps in all corners and it made a huge difference.

 

[agarwalro]

I just noticed that the bar's vertical surface is perfectly placed for reflecting front sounds. Maybe add some damping here?

 

[robc1976]

I just noticed that the bar's vertical surface is perfectly placed for reflecting front sounds. Maybe add some damping here?

You are correct, I am actually taking out the bar because it actually is 43" tall wich is taller than the back of the seats wich is causing reflections, flutter echo and who knows what LOL!!

 

[agarwalro]

How did you end up placing them?

 

[robc1976]

How did you end up placing them?

I ended up taking out the entire bar, and put the diffusor's above MLP and 3 in front of MLP, with some absorbtion mixed in and 4 diffusors in the back. It made a pretty great difference but I am think about replacing everything with the below, I have learned the foam absorbs mostly HF and Mid frequency and deadens the room a bit to much and the foam bass traps can also be improved. I got this foam super cheap so I will just resell it very cheap LOL!! But I am NOT saying the foam did nothing, it helped a great deal. I cahnged some trhings also and will post pics in a few.

Here is what I am thinking about doing:

These for the first reflection points on the walls and behind the speakers as well as reflection points on the ceiling:

GIK 242 Acoustic Panel. GIK Acoustics. Acoustic Panels and Bass Traps.

These for bass traps, they are 4' tall

GIK Tri-Trap. GIK Acoustics. Acoustic Panels and Bass Traps.

Diffusion over MLP and back wall: 9 (I have a air duct over MLP, don't mind putting screws thru it either.)

GIK Tri-Trap. GIK Acoustics. Acoustic Panels and Bass Traps.

Diffussion on 3 drop tiles in front of MLP:

GIK GridFusor. GIK Acoustics. Acoustic Panels and Bass Traps.