# Considering some acoustic treatment, seeking advice…



## kflory (Feb 6, 2010)

I have been working on revamping my audio/ht system and in the process have been using REW to tune my crossovers and have been on a tangent trying to analyze and understand the cause of the various peaks and dips to see what if anything I can do to smooth some of them out and perhaps improve upon what I am already quite happy with.

I certainly have lots more experimenting that I can do (seems unlimited) and time to take measurements is limited in trying to get the exclusive use of the room (and keep the rest of the house quite), so lot of time to theorize and make the most of the time I do get.

*Questions*
I have a number of questions, hopefully not too many for one thread:

1)	General comments on acoustic friendliness of cellular blinds (behind main speakers)?

2)	We are also considering replacing the cellular blinds as well as adding some additional treatment, so now would be a good time to try an influence those to provide better acoustical properties. 

3)	There are a few places I could add acoustical treatments on the walls. These would not be able to really address 1st reflection points, so would it still be worth while investing in them (will note the specific location below)?

4)	I have a pretty strong room mode at 37.7Hz which is probably attributed to the room length (2x) and width (1x), but limited to one potentially corner for bass traps (if at all). Would trying to address the one corner help enough to be worth the trouble (again, will note the one location below)?

5)	My ceiling is pretty high (10’) and treating the ceiling is not terribly appealing to me (nor I suspect my wife :nono. I can understand how this would be important for closed room with lower ceilings, but how critical/helpful is this for high ceiling for largely open rooms?

*Room Description*
The room is a large open room, roughly 15’w x 30’d x 10’h that has large opening to the adjacent rooms and the adjacent living/dining room area has a vaulted ceiling that is open to the second story of the house. Floor plan for first floor (target room highlighted by red box):









Below is the layout of the room and speaker placement (area highlighted in red above):









The room (and adjacent rooms) have lots of hard materials; hardwood floors, tile floors, granite counter tops, family room and kitchen cabinetry and wood furniture, etc. with the softer materials being the leather chairs and couch and area rug between the speakers and the main listening position which are in the seats in front of the tv/speakers, but the when entertaining, the kitchen island and adjacent kitchen nook are also used and serviced

The window coverings for the windows behind the speakers are cellular blinds (which I would assume has a better acoustical property that a hard wall), but the other window covering in the room are wood shutters (good for blocking the light from the windows on the tv, but probably at the expense of the acoustics). 

Below are some pictures of the room for more detail…





































The potential spots where I could place treatments would be:

a)	The area above the couch, replacing the picture there with two or three panels. Thinking something like the GIK art panels, easy to sell on the wife since we need something bigger on that wall anyway.

b)	The area above the fireplace, thinking another GIK art panel could go here.

c)	Potentially trying to add a bass trap behind the media rack.

d)	Last and certainly least would be replacing the picture in the kitchen next to the fridge, again potential another GIK art panel here (but more skeptical about this location).

*Speaker Placement Limitation*
Unfortunately I am breaking a lot of general guidelines due to restriction/limitations with speaker and furniture placement:

•	Listening position is 43% the room depth (vs. the 38% starting guideline).

•	Speakers are positioned rather close together (although sound stage sound fine to me) as moving the left speaker out would put it in the path to the door to the backyard and the moving the right speak out would put it closer to the couch (and opted for a little space). 

•	Sub is facing lateral to the front/main speakers (although REW showed no difference with the sub directed toward the listener).

*Current Room Response & Waterfall*
Below are the current response (wo/filter, 1/3, and 1/1 octave filtering) and waterfall with both mains and sub/

















A bit of a data dump, but figured I would provide as much info as possible.

Thanks in advance for any comments or feedback.


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## bpape (Sep 14, 2006)

The room is certainly very lively and any treatment would be welcome. Based on the waterfalls, there is certainly also the need to address ringing in the bottom end.

You're not going to do a lot for your frequency response unfortunately without being able to move things around which sounds like isn't an option really.

The cellular blinds are doing little to nothing. They might do a bit of something from a few kHz up. The leather furniture is still reflective at higher frequencies though it will help a bit in the lower mids through bass - just not a lot of surface area though.

In short, I guess the summary is do as much as you can wherever you can given the restrictions in the space in terms of placement and positioning.

Bryan


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## gsmollin (Apr 25, 2006)

I would recommend a change of venue for the theater because with that window wall behind your video screen you will never have a good sound stage, and daylight viewing will be compromised, unless your venetian blinds work a lot better than mine.

If you are stuck with this layout, then treat the entire wall behind the speakers that is not window. Use the Corning rigid fiberglass and make/buy custom panels to fit all that area, floor to ceiling. a membrane bass trap in the corner behind the sub would be good. Anything along the side walls, panels with artwork or whatever passes WAF. You can use panels or furniture to block first-reflection points.

The kitchen area behind you isn't terrible, since it functions as a diffusive rear, within limits. The real sin is the windows and hard surfaces behind and around the speakers. Your REW curve shows comb filtering above 200 Hz. I would guess that is coming off of the hardwood doors to the left of the speakers.


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## kflory (Feb 6, 2010)

Thanks for the feedback Brian!



bpape said:


> Based on the waterfalls, there is certainly also the need to address ringing in the bottom end.


Sure, but I am at a bit of a loss was to what if anything can do here (other than potentially try a bass trap in the corner but not sure how much good that would do if any. I am assuming this is due to the length and width of the room.



bpape said:


> The cellular blinds are doing little to nothing. They might do a bit of something from a few kHz up.


We have also had heavy drapes hanging here as well for a while (in addition to the blinds), but did not really seen any difference in the measurements (and they were too dominating for the room and made it too dark, so we removed them). As I mentioned, we are looking at doing more with the windows (wife is thinking of Roman shades here) which is why I was wondering, given the restrictions, if there something that you would recommend for covering the windows that may also have some acoustic benefits?


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## bpape (Sep 14, 2006)

Drapes would help higher frequencies only so you wouldn't notice a lot in the measurement set other than waterfalls but that's really a non-issue.

Dark is good in a home theater 

Bryan


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## kflory (Feb 6, 2010)

Thanks for the feedback gs!



gsmollin said:


> I would recommend a change of venue for the theater because with that window wall behind your video screen you will never have a good sound stage, and daylight viewing will be compromised, unless your venetian blinds work a lot better than mine.


Really not an option outside of moving and really not that displeased with the sound to buy a new house :bigsmile:.


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