Symmetry

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Desertpilot

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Symmetry
« on: 15 Mar 2021, 12:10 am »
As I think about this issue I thought I'd ask forum members what they think.  My listening/hometheater room is part of a great room in our home.  There is a side wall 2 feet from the left speaker.  There is no side wall on the right.  Question.  How important is symmetry?  Should I consider placing a diffusion panel 2 feet to the right of the right speaker?

The specific listening area is 14 feet wide and 14 feet deep (MLP) with a 12 foot vaulted ceiling.  However, room size is much larger, 30 feet long by 40 feet wide (living, dining, kitchen areas).  My system sounds pretty good now (speaker placement and GIK panels).  But, getting a couple 2 inch diffusion panels (to put next to left and right speakers) is something I've thought about for a while.  I cannot relocate any speakers or equipment as a solution.



Thanks
Marcus

pompon

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Re: Symmetry
« Reply #1 on: 15 Mar 2021, 06:20 am »
Symetry is ideal to have perfect channel match.

Try to move one gik panel and put at the first reflexion point of the right speaker to see what happend.

Or try to diffuse more then left wall / or put a deflector to not have sound coming from the first reflexion point (you can put one of your gik with angle to send the sound elsewhere).

JWL.GIK

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Re: Symmetry
« Reply #2 on: 15 Mar 2021, 02:30 pm »
Symmetry is great where possible.... if the room itself and the setup are symmetrical then I will try to preserve that symmetry.

But for situations like yours where the room/setup itself is not symmetrical, then we can use treatments to try to "re-assert" some acoustic symmetry, that is, try to make both sides sound more similar to one another. Specifically treating the closer wall for early reflection will help..... treating the opposite side similarly (perhaps with freestanding devices) will help more. And of course a good bass trapping strategy throughout the room will help the entire room be more consistent in bass response etc.

youngho

Re: Symmetry
« Reply #3 on: 15 Mar 2021, 02:45 pm »
Symmetry is much more important for stereo than multichannel. Still, consider broadband (so thicker) absorption on the left wall, both near the speaker and at the first reflection points for the front three speakers, and toe-in the left and right main channels, which seem to be relatively forward-firing in the picture.

Desertpilot

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Re: Symmetry
« Reply #4 on: 15 Mar 2021, 07:05 pm »
Sorry, old photo.  New one below.

I appreciate the comments.  What I've done so far.
1.  Behind the blackout curtain, on the left, I installed a 2inch thick absorption panel.  Since no reflections on the right, I tried eliminating the reflections on the left.  I can't hear a difference but it is there.
2.  I pulled the speakers out farther from the wall (on to the carpet).  They are now about 5 feet from the front wall and 11 feet from the MLP.  I'm actually pretty impressed with the improvement in soundstage depth (important for me as I listen to classical music).
3.  Yes, they are toed-in.

James, yes!  I will be speaking with you soon about all of this and more bass traps.  I am currently installing upgraded crossovers to my SVS Ultra speakers (see GR Research circle).  For testing purposes, I pulled off my back wall a couple of impression series panels that I will put near the left and right speakers to see if that makes a significant improvement in symmetry.  Once the speaker upgrade is done I will run REW to produce some measurements.  We will go from there.




Thanks again everyone.
Marcus

BobM

Re: Symmetry
« Reply #5 on: 15 Mar 2021, 09:07 pm »
I had a similar situation with a wall on the right and nothing on the left. I did put a GIK panel in 1st reflection points on both sides, standing the left one up in free space. yes, it definitely helped, but I agree, a wall on both sides would have been better for compressing the room evenly.

Tyson

Re: Symmetry
« Reply #6 on: 15 Mar 2021, 09:36 pm »
Bass is also loading unevenly in that room.  Try moving both subs to the side with the opening and see if that allows for more even bass pressure throughout the room.

Desertpilot

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Re: Symmetry
« Reply #7 on: 16 Mar 2021, 12:57 pm »
Hi Tyson,  Thanks for the tip but I am already pressing my luck with the Wife Approval Factor (WAF).  I don't see any way she would let me move the subs to the open side of the room.  Once I complete the SVS Ultra speaker upgrades and run REW, I'll be in a better position to consider bass traps and repositioning the subs.