[K Shep]

Cool, so if you did it yourself, is taking that area out not an option?  I'd think it would open up other placement options for you ... and the symmetry would help even out the spatial cues in the time domain, giving you better overall imaging.

Carpet, insulation, framing, electrical, prime and paint.

Not an option.  The room will remain and I will treat it to the best of my ability.

[K Shep]

Today I built a frame using 3/4"x1-1/2" doug fir material.  I stretched fabric around the frame and stapled.  I placed the 703 material in place and with the frame in place it looks pretty clean.  I will make some adjustments but the fit and finish ain't bad. 

[K Shep]

In a chunk style absorber or anything else more than 4" thick, 705 isn't going to buy you anything in terms of additional performance.  It'll just cost you more money. The 703 will actually perform better than 705 in that type of arrangement.

Also, if you don't have the space and/or need to save some cash, you can cut 8 triangles from each sheet at 17x17x24" instead of 4 at 24x24x34".  That'll get you 16" of height per 2" thick sheet.

Bryan

I plan to use the 17x17 option for the bass trap near the back window.  I was concerned that the trap wouldn't be deep enough, thank you for the recommendation.

[Glenn Kuras]

so how is it sounding??

[K Shep]

The room sounds different!  I have moved the existing treatments and added bass traps.  I will be building and adding more this week.  The plan is to have the room changed and compete by the end of this weekend so I will post photos and before and after measurements. 

The area behind the speakers, left side of the room near the window is a challenge.  That area is a large natural bass trap.  I may purchase 2 GIK trip traps and place them in that area.  I am considering the "finished" GIK's so that I may move them.  I must open the window in the summer.  Please share your recommendations I am puzzled with what to do in that space.

Here is a photo, the area where the green bean bag chair sits.

[Big Red Machine]

Are those cherry veneer?

[BobC]

I picked up 12 sheets of OC 703 today and cut enough panels to build one of the bass traps.

I'm curious to know, is there an acoustical advantage to stacking several triangles (stacked vertically) versus stacking progressively narrow sheets with a 45 degree edge (stacked front to back)?

[Jeffrey Hedback]

none at all...six one way 1/2 dozen the other acoustically.  It just is easire to cut and stack the triangles for most.

[Big Red Machine]

I'm curious to know, is there an acoustical advantage to stacking several triangles (stacked vertically) versus stacking progressively narrow sheets with a 45 degree edge (stacked front to back)?

Can't imagine any that we could hear or even measure assuming you basically fill the corner.

[BobC]

Do you glue these sheets together?  And if so, what type of glue is recommended?

[K Shep]

Do you glue these sheets together?  And if so, what type of glue is recommended?

I've used spray adhesive from 3M that I purchased from a local hardware store.  You spray both surfaces wait 15-30 seconds then bond.  I did not adhere the triangles together, I used the adhesive to wrap the acoustical fabric around the 2x4 panels that I hanged.

http://solutions.3m.com/wps/portal/3M/en_US/3M-Super-77/Super77/

Here is an alternative from ATS Acoustic, less expensive than the 3M product.

http://www.atsacoustics.com/item--Ram-Tack-Spray-Adhesive-12-oz--1019.html

[K Shep]

Are those cherry veneer?

Yes, curly cherry.  They're no longer in my possession.

[Big Red Machine]

Do you glue these sheets together?  And if so, what type of glue is recommended?

Triangles and gravity work for me.  That glue is icky!

[bpape]

'Zactly.  Just stack 'em up unless they're frameless like these and would need to be moved.  No acoustical benefit in joining them. 

The ONLY benefity to potentially having ONE shee cut as the face and 45's on the back was if you wanted to bond a membrane like FSK on it to limit upper mid and high frequency absorption. Other than that, stacked triangles are just a whole lot easier to cut and a lot less waste.

The cavity in the back with the bean bag will have its own resonances certainly, just as the narrower area behind the speakers will.  The one benefit is that the glass window will allow some of the bass energy to pass out.  I also see what looks like at attic entrance on the left wall back there. That's likely much less dense than the walls or even the glass and will also likely pass some bass out of the room. 

If it were me, I'd probably use something like 2 Monster panels, 1 on stands.  1 back by the beanbag, the other straddling the corner where the bookcase is.

Bryan

[K Shep]

'Zactly.  Just stack 'em up unless they're frameless like these and would need to be moved.  No acoustical benefit in joining them. 

The ONLY benefity to potentially having ONE shee cut as the face and 45's on the back was if you wanted to bond a membrane like FSK on it to limit upper mid and high frequency absorption. Other than that, stacked triangles are just a whole lot easier to cut and a lot less waste.

The cavity in the back with the bean bag will have its own resonances certainly, just as the narrower area behind the speakers will.  The one benefit is that the glass window will allow some of the bass energy to pass out.  I also see what looks like at attic entrance on the left wall back there. That's likely much less dense than the walls or even the glass and will also likely pass some bass out of the room. 

If it were me, I'd probably use something like 2 Monster panels, 1 on stands.  1 back by the beanbag, the other straddling the corner where the bookcase is.

Bryan

The attic entrance is in the floor.  The unfinished section back by the window is just that an unfinished access door to the area behind the wall, can lights etc.  I may draw a plan today and post it.  That may make it easier to discuss.

Thank you for your input Bryan.

[TooManyToys]

Today I built a frame using 3/4"x1-1/2" doug fir material.  .......

Have to ask this, where did you get the doug fir of that size?

I used to be able to get it at my local yard, but they went out of business.  Now I've gone to several others and they just keep telling me to buy a 2x4 and cut it down.

[K Shep]

Have to ask this, where did you get the doug fir of that size?

I used to be able to get it at my local yard, but they went out of business.  Now I've gone to several others and they just keep telling me to buy a 2x4 and cut it down.

A local yard called "Discount Builders" in San Francisco.  They have many different shapes and sizes of molding and trim material.  Large demand for molding in S.F.

[Nuance]

If it were me, I'd probably use something like 2 Monster panels, 1 on stands.  1 back by the beanbag, the other straddling the corner where the bookcase is.

Bryan

Cool, that's what I told him too (over the phone).  Glad to know an expert thinks the same thing (you, of course).  Guess I am learning a thing or two about this room treatment stuff. 

[K Shep]

My latest build.  3 each 2"x2'x4' framed using 1"x6" material.  I will wrap the frame with fabric and attach a stand (legs).  Not as clean as I had hoped but the fabric will cover the imperfect corners.

[Nuance]

Things are looking great, Kirk.  I am very excited for you!