[andycsb]

Hello Guys,

I know it's probably been asked to death. But here goes...

Room is approx 10ft x 14ft x 10ft. Speakers (monopole) along the short wall. Front wall (behind speakers) lightly draped 4 windows. Corner traps at each corner. Side wall 1st reflection points treated by 2ft x 4ft 4inch thick (wood framed) foam panels. Back wall treated with 4ft x 4ft 1.5inch thick foam panels directly behind listening position. Back wall not possible for diffusers as it's a wardrobe. Concrete walls with wood over concrete flooring.

Thinking of trying some diffusers since I have found a rather cheapish source...either QRD or SKYLINE. Made of paulownia wood (very similar to balsa).

Before I pull the trigger........

I know it's best to experiment with placement but I was wondering if I should even bother as my room looks kinda cluttered already and the preferred location would be at the side walls...ie... right after the 1st reflection point (nearer towards listener).  Or...if I really have to...2 panels in-between the speakers. From pictures of systems...preferred location for most seem to be along the front wall between the speakers.  Anyone with experience in placement at those 2 locations? What was the outcome?

I am hoping to achieve a more spacious sound however would like to avoid thinning or drying out the mids esp in the vocal band. Would QRD or SKYLINE diffusers be more appropriate in this application? Or should I just ditch the idea of diffusers and just go for more absorption.

Thanks guys!

[Vedder323]

Hello Guys,

I know it's probably been asked to death. But here goes...

Room is approx 10ft x 14ft x 10ft. Speakers (monopole) along the short wall. Front wall (behind speakers) lightly draped 4 windows. Corner traps at each corner. Side wall 1st reflection points treated by 2ft x 4ft 4inch thick (wood framed) foam panels. Back wall treated with 4ft x 4ft 1.5inch thick foam panels directly behind listening position. Back wall not possible for diffusers as it's a wardrobe. Concrete walls with wood over concrete flooring.

Thinking of trying some diffusers since I have found a rather cheapish source...either QRD or SKYLINE. Made of paulownia wood (very similar to balsa).

Before I pull the trigger........

I know it's best to experiment with placement but I was wondering if I should even bother as my room looks kinda cluttered already and the preferred location would be at the side walls...ie... right after the 1st reflection point (nearer towards listener).  Or...if I really have to...2 panels in-between the speakers. From pictures of systems...preferred location for most seem to be along the front wall between the speakers.  Anyone with experience in placement at those 2 locations? What was the outcome?

I am hoping to achieve a more spacious sound however would like to avoid thinning or drying out the mids esp in the vocal band. Would QRD or SKYLINE diffusers be more appropriate in this application? Or should I just ditch the idea of diffusers and just go for more absorption.

Thanks guys!

How about these guys? http://www.piaudiogroup.com/Sound_Diffusors.html

[jk@home]

This article was helpful for me in determining where absorption or diffusion goes:

http://arqen.com/acoustics-101/reflection-free-zone/

[timind]

When I was working on my room a few years ago I was advised against diffusers as my room is too small. It was explained to me that in order for diffusers to be effective there needs to be 6-8 feet between diffusers and your ears.

My room is 12x12.

[JLM]

1st, visit the GIK circle here at Audio Circle and give them a call.

2nd, lose the foam which as best is a narrow (frequency) band absorber. 

3rd, lower the ceiling to 8ft (assuming one of your 10ft dimensions is room height).

4th, pull speakers/listening chair away from all walls (speakers at unequal distances from front/side walls).

5th, replace foam with high density Owens Corning 703 fiberglass (one of the best wide band absorbers) at first reflection points. 

6th, if you still want diffusion make sure it's depth is random (quadratic), made from dense material (not absorbent), try to go for blocks (not strips that only work in one plane), locate at first reflection points, and realize that diffusion requires depth to work so the most effective are 7.5 inches deep but only cover down to roughly 1,100 Hz.  Go to http://www.pmerecords.com/Diffusor.cfm for the best recipe I've found.  Note that each 18 inch x 18 inch x 8 inch panel will weigh 23 pounds but are cheap/easy to DIY.

[JWL.GIK]

For a room that size, my preference would be to use Binary Amplitude style diffusion, which is actually a mixture of absorption and diffusion. You can go phase grating (skylines or QRDs), but you have to be a certain distance away from those for them to be really effective. That will limit you in terms of the frequency response of the diffusors.

Details here: http://www.gikacoustics.com/decoding-diffusion-acoustic-solutions/

[Mike-48]

I have used binary diffusion (as recommended by JWL) in spots only 2 ft from my head. It worked very well, killing irritating reflections without deadening the sound. If you go for 6" thickness you also get some bass trapping,  I would think.

[andycsb]

Thanks Everyone for your input. Really appreciate it.

If I do replace the foam in my absorptive panels with owens corning 703 ... what material would be most effective in containing loose particles from leaching through the acoustic fabric?

Also, I have been reading that the minimum distance from diffuser (skyline or QRD...or does it depend on type used) to listener is around 6 feet. Would that be about right? Binary diffusion sounds very interesting.

Thanks.