# New REW Results & Tackling Room Acoustics with Treatment(s)?



## xfiddle (Jan 7, 2010)

I recently have finished a few days of room testing and measurements with REW and I'm about to start working on a plan to treat the room. I spent a couple days moving speakers around for the optimal placement given my restraints and I think I have come up with the best spot for my subwoofer. I've included my mdat files here for you to view which includes separate Left, Right, and Sub only responses.

From what I can gather the best placement for my sub is behind the front left main speaker and with the max output setting. With the max extension setting I'm not sure I could use my behringer 1124p to cut the gain below 20Hz? Or is max extension better because of the lowend rolloff starts at 15Hz vs 20Hz? I wasn't sure how much stock to put into the predicted graphs of REW after applying theoretical EQ filters.

Anyways, here are a few pictures of my room as well as a crude sketch of the dimensions. The ceiling is 7ft high to the suspended tiles with a 2" clearance below 10" deep joists to a final "real" height of 8ft wood flooring above.

I know I'll probably need to tackle numerous things and eventually I'll probably go with some sort of realtraps or GIK solutions to appease the wife but for right now I just need to prioritize a stopgap of DIY measures.

To start with I was thinking of filling the ceiling joist area with 9.5" r-30 fiberglass rolls at least a few feet wide around the main listening area perimeter. I'm not sure how effective that would be for the low frequencies however and also whether or not I should just fill in as much of the ceiling as possible instead of the wall-ceiling perimeter.

Any thoughts on what treatments to prioritize? Should I worry about corners before reflection points?

I do also have a package of 3.5" r-13 ultratouch I bought for more than half off at $30 which I can make broadband absorption panels with. I thought about making a superchunk trap with the ultratouch but I assume multiple panels would be better than 1 trapped corner. Plus, I've read that ultratouch doesn't really gain much more effectiveness in thicker amounts but is comparable to rockwool and dense fiberglass at 4" thick.

Any thoughts are appreciated!


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## bpape (Sep 14, 2006)

Insulation above the drop tile ceiling is an inexpensive and invisible way to get a good amount of broadband bass control in the space. 

Not sure where you heard about the ultratouch. It works very well and increased thickness does indeed extend how low it will reach. I would agree though that doing 2 smaller corner panels instead of 1 large one would be a better option. Symmetry left to right between you and the speakers is also important.

One other comment, you seem to have an extreme amount of toe in. That might work pretty well for one seat but it's not going to be great for any of the others.

Bryan


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## xfiddle (Jan 7, 2010)

bpape said:


> Insulation above the drop tile ceiling is an inexpensive and invisible way to get a good amount of broadband bass control in the space.


So filling as much space as possible is the best route rather than an area around the perimeter? I'm guessing once I get near the area where to room opens up to the stairs that gains from insulating that portion of the ceiling would be limited.



bpape said:


> Not sure where you heard about the ultratouch. It works very well and increased thickness does indeed extend how low it will reach.


I read quite a few threads on the gearslutz acoustic forum concluding that the material itself had higher gas flow resistivity, so that when doubled or tripled up the absorption improved some but not nearly as much as doubling up on fiberglass or rockwool especially in the lower frequencies. I figure value to performance wise I should just make as many panels as possible. 



bpape said:


> I would agree though that doing 2 smaller corner panels instead of 1 large one would be a better option. Symmetry left to right between you and the speakers is also important.


Do you think I should put a single panel straddling the corner underneath the left back surround? The right back side opens up into the room entrance so no panel options there.

With the utratouch I figure I'm limited to 15" or 30" wide panels due to the 15" material width. I have enough ultratouch to theoretically make eight 2.5'x4' panels cutting each separate bat once down the middle. Should 15" wide panels be sufficient for reflection points or would the 30" be better suited? I've also been considering small 15"x15" square panels for the room corners.

My right main speaker doesn't have a 1st side wall reflection point due to the room opening so I'm guessing a 30" panel on the respective left side would be fine. I'm not sure the best method or which other reflection points to treat after that specific one.
I am somewhat worried about making the room too dead but maybe I would have to put a lot more material in the space for that to be a problem? 



bpape said:


> One other comment, you seem to have an extreme amount of toe in. That might work pretty well for one seat but it's not going to be great for any of the others.
> 
> Bryan


I am being a bit selfish with that toe in :hissyfit:, but since my HT serves dual purpose for my music setup I've kept the mains in that position (and I love the soundstage and imaging of the paradigms in that configuration). I'm probably the sole listener/viewer 75% of the time so I figure I can "toe-out" the speakers when wife or I have guests come over.


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## bpape (Sep 14, 2006)

In the ceiling, do over your head and then again around the perimeter.

I sold and used ultratouch for years. I can tell you that with additional thickness, it definitely extends the bottom end. Once you get beyond say 3", you're really not changing anything above 100hz or so for the most part.

How wide the absorbers need to be for reflections depends on the zone you need to cover.

Small panels in the corners aren't going to do a lot.

Bryan


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## bpape (Sep 14, 2006)

In the ceiling, do over your head and then again around the perimeter.

I sold and used ultratouch for years. I can tell you that with additional thickness, it definitely extends the bottom end. Once you get beyond say 3", you're really not changing anything above 100hz or so for the most part.

How wide the absorbers need to be for reflections depends on the zone you need to cover.

Small panels in the corners aren't going to do a lot.

Bryan


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## xfiddle (Jan 7, 2010)

Well I cut and installed about 150 sq feet or r-30 fluffed to about 10" deep in the ceiling tonight. Haven't had a chance to run REW yet but it did seem to make a difference in the resting dB of the room. Also the noise transfer to upstairs is damped quite a bit more.

What is the best way to utilize REW in determining the next steps in acoustic treatment? Eventually I'll probably make superchunk traps with fluffy fiberglass, rockwool, or ultratouch for the corners but I'll probably have to wait until spring for that or maybe late january. I know that for the 1st or 2nd reflection points I don't want any HF reflected but should I utilize plastic sheeting on corner panels or ceiling panel over the listening position?

One final thing I forgot to ask before is how I should handle that steel support beam behind the couch? Its not in the direct path of any speaker but I assume that it is reflecting some of the higher frequencies from a few speakers including the mains. Would a wrapping of .5"-1" polyester batting covered in a breathable cloth be fine or should I consider a different absorption material/thickness?


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## bpape (Sep 14, 2006)

I'd not worry about the beam too much at this point.

As for the front corners, what needs to be done is to assess what the target decay time range should be in the room, compensate for the construction and furnishings in the room and how they impact it, then you can see if any additional HF absorption is warrented.

All of that said, the front wall for multichannel should normally be 100% dead to stop any reflections from the surrounds contaminating the front soundstage.

Bryan


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