Absorption or Diffusion?

[Tmort]

Yes, I have diffusion behind my panels. I tested both absorption and diffusion. Imaging and soundstage are excellent with both. But I found absorption deadened the sound too much. Diffusion provided a lot more of the ambiance and spaciousness that electrostats are known for and a threw a wider, deeper soundstage. You can get used to either sound, but I preferred diffusion. But in order for diffusion to work properly, you need about five feet between your speaker panels and the diffusors. If you have much less than that, you might be better going with absorption.

Ceiling treatments don’t really make a difference with electrostats because they don’t have any vertical dispersion, being a line source speaker.

Rich, I have a small room, 11x11 with a sloped ceiling front to back. Lots of hard surfaces except for carpet. My classic 9’s are roughly 32” stat to front wall, due to space constraints I can’t do much more than that.
I borrowed some absorption panels from a fellow ML enthusiast 2x4 in size and placed them behind the stats with very nice results.
Currently I’m discussing room treatment strategy with GIK acoustics and he’s steering me towards a 4” thick bass trap panel (Alpha series), that provides both diffusion (2 or multi-directional), and absorption.
Given your comments in this thread about strategy and distance to front wall plus my experience with absorption only currently, what do you think?

 

[Rich]

Rich, I have a small room, 11x11 with a sloped ceiling front to back. Lots of hard surfaces except for carpet. My classic 9’s are roughly 32” stat to front wall, due to space constraints I can’t do much more than that.
I borrowed some absorption panels from a fellow ML enthusiast 2x4 in size and placed them behind the stats with very nice results.
Currently I’m discussing room treatment strategy with GIK acoustics and he’s steering me towards a 4” thick bass trap panel (Alpha series), that provides both diffusion (2 or multi-directional), and absorption.
Given your comments in this thread about strategy and distance to front wall plus my experience with absorption only currently, what do you think?

I think the bass panel trap is a good idea. It should absorb the entire frequency range of the rear wave from the electrostatic panel. Whether or not the diffusion strips they put in those panels will help is an open question. I don’t have experience with them, so don’t know how effective they really are. Plus, with your panels being less than three feet from the front wall, there may not be an adequate time delay between the front and rear wave to prevent image smearing. I think you would just have to try them and see what results you got compared to absorption alone. They may work great for your situation.

 

[Tmort]

After a phone discussion he’s of the impression a strictly absorption approach is best.
https://www.gikacoustics.com/product/gik-acoustics-244-bass-trap-flexrange-technology/This is what I’ll almost certainly be going with on front wall and on immediate return wall each side.

 

[MisterB]

Hi Tmort- For what it’s worth, I tried floor to ceiling GIK Impression corner bass traps with the Gatsby pattern diffusion plates in a similarly sized room with my 11A’s. I did not feel they did much to help my particular issues, mainly bass buildup along the front wall and a somewhat narrow soundstage. I was hoping the diffusion plates would give the sense of a wider soundstage. In the end, I felt the corner traps just made the room feel even smaller. I eventually took them out, hung floor to ceiling drapery on the front wall and moved the 11A’s farther away from the front wall and as far away from the side walls as I could. The horizontal center of the panel (measured at the top) is 48” away from the front wall and 28” from the side wall. I am very pleased with the sound at this point.

I’m by no means an expert on any of this, but this worked very well for me. The drapery gives just enough absorption it seems. I never tried the corner traps without the diffusers. I do think absorption-only behind the ML’s is probably more appropriate than the traps with the diffusion plates that I tried. GIK recommended the diffusion plates to me. In retrospect, I wish I would have tried the kind of panels you’re considering. Fortunately for me, I was able to pull my Logans farther out into the room than it seems you’re able to. Best of luck! Let us know how it all works out.

 

[Tmort]

Hi Tmort- For what it’s worth, I tried floor to ceiling GIK Impression corner bass traps with the Gatsby pattern diffusion plates in a similarly sized room with my 11A’s. I did not feel they did much to help my particular issues, mainly bass buildup along the front wall and a somewhat narrow soundstage. I was hoping the diffusion plates would give the sense of a wider soundstage. In the end, I felt the corner traps just made the room feel even smaller. I eventually took them out, hung floor to ceiling drapery on the front wall and moved the 11A’s farther away from the front wall and as far away from the side walls as I could. The horizontal center of the panel (measured at the top) is 48” away from the front wall and 28” from the side wall. I am very pleased with the sound at this point.

I’m by no means an expert on any of this, but this worked very well for me. The drapery gives just enough absorption it seems. I never tried the corner traps without the diffusers. I do think absorption-only behind the ML’s is probably more appropriate than the traps with the diffusion plates that I tried. GIK recommended the diffusion plates to me. In retrospect, I wish I would have tried the kind of panels you’re considering. Fortunately for me, I was able to pull my Logans farther out into the room than it seems you’re able to. Best of luck! Let us know how it all works out.

Panels ordered today, I’ll let the group know the results!