# multi-purpose room renovation



## bjmsam

We recently purchased a house with a large area in the basement that serves as both a home theater and a family room. The house was built in 1973 and the space is quite dated, featuring wood paneled walls and a drop ceiling with fluorescent fixtures. I've seen good ideas presented on this site and thought I would throw a few ideas out there in case anyone has suggestions before we get started. Here are photos of how it looks now:

























































I am quite happy with the electronics (65" Mitsubishi DLP, classic Teledyne AR-9 front speakers, Definitive Technology side and rear surround speakers, B&K Reference 30 Pre-Pro, Adcom GFA-585 front and GFA-2535 surround amps) so the budget will primarily be for room treatment (acoustics, lighting, furniture, etc.). I'm envisioning a more attractive acoustic tile throughout the room with the area above the theater slightly raised with recessed lights on a dimmer (could also frame the area with track lighting, LED rope lighting, etc.). The wall behind the screen should be dark (a heavy pleated curtain would be effective acoustically as well) and the equipment should be in a proper rack. It would be neat to have motorized light-blocking curtains across the wall of windows (there is room on either side to accommodate them without obscuring any of the glass when open).

Dipole side surrounds (firing front/rear) and traditional rear surrounds will have to be installed in the ceiling (the rears _could_ go in the back wall, but that is not an option for the sides), perhaps angled where the ceiling height changes as mentioned above.










I used Room EQ Wizard to produce the following measurements (some of which I am still trying to decypher):































































































































Bass traps and diffusers may do the trick, but since the wood paneled walls are also in need of attention, perhaps there are options other than surface treatments worth considering. If too expensive, perhaps the walls can simply be painted and corners treated with OC703 (or similar) panels covered with attractive fabric. The sectional in the photos has been removed (it was not present during measurements above) and will likely be replaced with an upholstered sofa and loveseat for the area in front of the fireplace and a matching third recliner for the theater (they swivel and can be turned that direction when in "family room mode"), though I'm admittedly troubled by reflections from the leather headrests.

Since it's free, I submitted a drawing to Auralex and received the following Personalized Room Analysis:



















I hope that's enough food for thought. Input would be most appreciated!


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## bjmsam

The images are also in a Picasa album.


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## SierraMikeBravo

Hi bjmsam,

A couple of things. 1. Curtains in the front behind the speakers will not help at all. The primary purpose of treatment in the front and near front side walls is to deal with SBIR (Speaker Boundary Interfence Response) issues through broadband absorption. Curtains do not provide this is the broadband sense. They will take care of high frequencies, but not the freqs you are really trying to target which is the mid and higher bass frequencies. 2. Based on the way your room is sized and shaped, it will be difficult to come up with a effective treatment strategy that you will be extremely pleased with the end result sound wise. It can be done, but it will be difficult considering the amount of stone, glass, shape etc. 3. Bass trapping is actually accomplished to some extent through your windows (they are pretty transparent to low frequencies and it realizes it wore out its welcome, so it doesn't come back in :clap, but if your measurments are any indication, you have lots of trouble with decay times in the mid bass frequencies (not sure how you did it, but we'll take it at face value) which can be handled by fuzzy stuff and preferably diaphragmatic absorbers. Anyway, my two cents. Hope this helped!


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## bjmsam

Thanks for the reply. That's the sort of informed insight I hoped folks would offer.



SierraMikeBravo said:


> [Curtains] will take care of high frequencies, but not the freqs you are really trying to target which is the mid and higher bass frequencies.


Unless a better idea is suggested, I will instead pursue a row of bass trap panels across the front wall as I plan to do for the back wall. The approach depicted in the RT60 graph thread looks interesting...




SierraMikeBravo said:


> Bass trapping is actually accomplished to some extent through your windows (they are pretty transparent to low frequencies and it realizes it wore out its welcome, so it doesn't come back in :clap


If heavy curtains over those windows absorb high frequencies, then that wall will presumably be in good shape.




SierraMikeBravo said:


> Based on the way your room is sized and shaped, it will be difficult to come up with a effective treatment strategy that you will be extremely pleased with the end result sound wise.


How would a professional tackle this challenge?




SierraMikeBravo said:


> if your measurments are any indication, you have lots of trouble with decay times in the mid bass frequencies (not sure how you did it, but we'll take it at face value) which can be handled by fuzzy stuff and preferably diaphragmatic absorbers.


This was my first attempt at using REW, so I likely made mistakes. The SPL meter was at the center listening position, which is ~17' from the front wall and ~12' from the back wall.


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## SierraMikeBravo

Hi bjmsam,

Regarding the curtains along the window, to some extent yes, but you often like preserving high freqs to some extent, but it is more ideal to have them somewhat diffuse. To some degree your windows provide some help, but they can also rattle at certain freqs which can become annoying. The other aspect is that windows are transparent to outdoor sounds, too which raises the noise floor in your room. This reduces your dynamic range of playback, but that gets into sound isolation so I digress.

Not quite sure what you may be referring to as bass traps along the front wall. More specifically, I would use something equivalent to Owens Corning 705 covered with acoustically transparent fabric placed in strategic spots or covering the whole wall. There is a lot going on along the front wall the garners serious attention.

Regarding how a professional would handle it, well, it would take some work, and it all depends on what compromises you are willing to accept. A true professional should lay out all options, explain why the options are the way they are, the benefits and the consequences, then let you decide how you wish to proceed. Hope this helped some more! :bigsmile:


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## bjmsam

SierraMikeBravo said:


> Not quite sure what you may be referring to as bass traps along the front wall. More specifically, I would use something equivalent to Owens Corning 705 covered with acoustically transparent fabric placed in strategic spots or covering the whole wall. There is a lot going on along the front wall the garners serious attention.


I just ordered two boxes of 2'x4'x2"x24 Roxul SAFE®, which should be enough material to build quite a few panels for the walls and corners. I welcome suggestions regarding thickness and placement.


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## SierraMikeBravo

Hi,

Like I mentioned above, it would take some work, as in analysis, to determine the best treatment type and method.


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## bjmsam

SierraMikeBravo said:


> Like I mentioned above, it would take some work, as in analysis, to determine the best treatment type and method.


Well, I have REW and the desire to learn...

BTW, I have positioned the speakers according to AR's guidance:














































I have all three level controls flat on both speakers.
Other relevant info from the manual:


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## SierraMikeBravo

bjmsam said:


> Well, I have REW and the desire to learn...


REW was not _quite_ the analysis type I had in mind. I also have a continuos desire to learn, too! :T In fact, I had such a desire, it ended up costing me $50,000+ on education and 10 years to learn it so far! :coocoo: All that did though was give me a license to learn more!


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## bjmsam

I'll just have to do my best by trial and error! Thanks.


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## SierraMikeBravo

Best of luck to you!:T


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## fractile

The dimensions and wall structure/surface of the room are primary. It looks like the room modes are at 20 and 44Hz; the walls reflect around 2.2kHz or something; typical room response for this type of structure.

You can do a lot of things to reduce the upper frequency.

I'm learning about low frequencies. There is the bass-trap option and I'm also looking at the active option of distributed sub-woofers, to push out that void?


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## bjmsam

So far I've built three corner traps and one panel, and while they have made a difference (I'll fire up REW once the rest are built and mounted), surely none are effective at such low mode frequencies.




























Are Mio Acoustic Weave panels worth considering for rear wall diffusion of higher frequencies, or would I be better off building QRD diffusers or an array of small broadband panels?
























































This appears to be the acoustical analysis (posted here):


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## DanTheMan

That drop ceiling looks like one giant bass trap to me. Just add pink stuff in a plastic sack. Then see where you are.

Dan


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## bjmsam

Thanks for the suggestion! That would be far cheaper than fiberglass tiles such as the PrimAcoustic StratoTile but may complicate access above.










Incidentally, I found this post in support of the Mio wall treatment mentioned above.



Lonely Raven said:


> I'm also playing around with some of this 3D wallpaper. This stuff actually diffuses noticeably, and not in a bad way at all. I just pinned it up where the OmniFusers will go whenever I get them done, just for grins.


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## bjmsam

SierraMikeBravo said:


> Curtains in the front behind the speakers will not help at all. The primary purpose of treatment in the front and near front side walls is to deal with SBIR (Speaker Boundary Interfence Response) issues through broadband absorption. Curtains do not provide this is the broadband sense. They will take care of high frequencies, but not the freqs you are really trying to target which is the mid and higher bass frequencies.





SierraMikeBravo said:


> I would use something equivalent to Owens Corning 705 covered with acoustically transparent fabric placed in strategic spots or covering the whole wall. There is a lot going on along the front wall the garners serious attention.



I would like to tackle the front wall next but am confused by what I've read about LEDE. Bryan's post below seems consistent with Shawn's advice above:



bpape said:


> In general, no such thing as too much on the front wall. Ideally, it would be 100% absorptive - at least for a multi-channel setup.





bpape said:


> Front wall in a home theater setup should be 100% dead. In your case, since you're kind of limited in space, I'd probably recommend 2" 703 or equivalent.


But then:


bpape said:


> 4" will likely be too much in that application.


Why is too much material a concern when striving for 100% absorption? I have just enough Roxul left to cover my 16' x 7'8" front wall at a depth of 4"...


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## bjmsam

Framed and filled with 2" Roxul AFB. Lots of pink stuff will go in that corner above the ceiling tiles.


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## bjmsam

Wall covered with 2'x4'x1" sheets of acoustic foam.


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## bjmsam

*Progress...*










Last weekend we painted all of the fake wood paneling in the room (except beneath and to the right of the acoustic wall) and this weekend we ripped out the old ceiling tiles, primed and painted the ceiling grid and installed new black ceiling tile in the theater area with 6" of Roxul AFB above the front row.


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## bjmsam

Ceiling tile is in (except for ducts) with 2'x4'x6" Roxul AFB above front and rear walls. Those Eclipse blackout curtains are really effective!





































Red trace is before, blue trace is after. Measurements taken with blackout curtains closed, rear wall untreated.


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## DanTheMan

Nice! You're pretty much in the sweet zone time wise across the board now. Congratulations.

Dan


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## bjmsam

It certainly sounds a lot different! The biggest remaining problem is a noticeable change in mid to high frequency sound as I move my head inches to the left and right at the listening position, which I assume is comb filtering. It does not go away with a thick pillow behind my head, so I assume it is from the ceiling or screen rather than from the headrest or rear wall. I don't know how to measure or confirm via REW.


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## DanTheMan

You'll definitely get a comb filtering effect from the speakers that changes with sideways movement. The more diffuse your sound field, the less you'll notice it. Dr Toole calls it the 'one-toothed comb'. You can find the acoustic center of your speakers using REW's RTA and watching for the notch to climb to the top of the graph.

The best way I found to reduce it's effects is to listen further away. The other way might be to start using diffusion.

Dan


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## bjmsam

I can find the acoustic center with my head! I'll try the RTA feature, and it would be interesting to compare measurements taken with the microphone at several positions inches apart, but where do I need diffusion? The side walls are angled such that they cause no early reflections, which leaves the ceiling (1728ABL acoustic tile with .55 NRC), floor (berber carpet) and 65" DLP screen.


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## DanTheMan

I never said "need". My point with the RTA wasn't 'to find the center'.

sorry, trying to be helpful.

Dan


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## bjmsam

Your replies have been very helpful. Sorry if what I wrote came across wrong. I'm merely exclaiming that the comb filtering is so pronounced that I expect the measurements to be pretty dramatic and that I would like to learn more about treatments that would help make the sound field more diffuse.


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## DanTheMan

No worries. All is forgotten. Seeing the measurements will give you a baseline from which you can objectively see improvements with later measurements. That way you have a sanity check. I like a sanity check from time to time.

Bryan Pape's Co. sells some quality diffusors that will drop into your ceiling. A couple of those at first reflections and beyond should help some. My other trick is distance.

Dan


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