[Rudy81]

Over the years I have looked into and added some basic room treatments to my HT. Previous absorber panels and a QRD diffuser were some of the items I added early on. However, I was well aware that my first efforts did not meet the requirements to be truly effective.

I recently decided to repaint my media room and that led to the idea of building some really effective bass traps and diffusers. One item I really did not want to work with again was fiberglass. I don't like working with it and have misgivings about hanging it all over an interior room in my home. So after quite a bit of research, I stumbled onto the UltraTouch denim insulation.

Research into denim's properties and cost made it a great candidate to use for my super chunk traps and absorber panels.

I had to order quite a bit of it, but it was the only way to get enough to make all the treatments. I decided on the R30 material that comes in 2'x4' pieces.

That material is just fantastic to work with! It can be a little bit dusty, but with careful handling, it is not an issue. The only difficulty I found was how to cut the pieces and end up with clean edges. After trying many items and ideas, including those from UltraTouch, I found that making a DIY 'press' and using a sharp knife is all you need.

 

[orion]

Great Idea Rudy. I cant wait to hear how the denim does for the acoustics in your room. Fiberglass is a pain to work with but it is proven. Ill follow you

 

[Rudy81]

The product is supposed to be 8.5" thick, but I found that even after a week of upacking, it barely gets to be thicker than 5.5".

After making the panels I ran REW to see what kind of effect the panels had on absorbing the audible frequency spectrum. Mind you, this is not the most scientific test, but gave me an idea of what to expect.

I placed the mic on a floor to wall corner, sitting a piece of insulation for the basic sweep. I then angled a panel over the mic and placed bare insulation on the open ends of the 'tunnel' and ran the sweep again.

This material seem like just what I needed to build my traps. Easy to use, not nearly as dangerous to my lungs and very effective.

 

[Rudy81]

Great Idea Rudy. I cant wait to hear how the denim does for the acoustics in your room. Fiberglass is a pain to work with but it is proven. Ill follow you

This is actually an after that fact post, so I will be posting quite a bit in the next day or so. I did a post on the Klipsch forum as I went along and decided to post here since there is so much interest in the DIY area. Stay tuned.

 

[bpape]

Just a couple of clarifications.

Fiberglass itself is not what most people are sensitive to, it's the chemicals in the binding agents like phenols and formaldehyde. That's why we use the ECOSE as it is a LEED certified green material even though it is fiberglass and is available in a variety of densities.

To the above, the UltraTouch can be fine for very thick panels like these. For other places, (front wall, side reflections, ceiling reflections, etc) it's density is not really desirable unless you're going to go at least 6" thick there. At approx 0.8 lb/cu ft, it's about 25% of the desired 3lb density.

 

[Rudy81]

This is the material thickness.

 

[Rudy81]

Just a couple of clarifications.

Fiberglass itself is not what most people are sensitive to, it's the chemicals in the binding agents like phenols and formaldehyde. That's why we use the ECOSE as it is a LEED certified green material even though it is fiberglass and is available in a variety of densities.

To the above, the UltraTouch can be fine for very thick panels like these. For other places, (front wall, side reflections, ceiling reflections, etc) it's density is not really desirable unless you're going to go at least 6" thick there. At approx 0.8 lb/cu ft, it's about 25% of the desired 3lb density.

Bryan, I'm sure many folks are sensitive to these chemicals. I have worked with both fiberglass and rock wool panels. My main issue with them is the effect on your skin when handling them as well as the dangers to your lungs if you don't use a respirator when working with the material.

You guys make some terrific products and I had originally looked into purchasing all my traps from you guys. However, I had some financial changes that forced me to re-evaluate my budget. It ended up that if I wanted to treat my room, the DIY route was the only method available to me.

I'm sure the professional products are more effective and scientifically proven than anything I can build. But, it will have to do for now.

 

[Rudy81]

As far as the fabric to cover the traps, I wanted to use the very nice FR701 from Guilfords of Maine, but once again my budget prevented 25 or so yards of material at around $25 a yard. I struck out to find a reasonable substitute and found a great deal at Hancock's for a very similar material on sale $7 a yard.

It turned out to be an excellent substitute. Phisically, the FR701 and this substitute are nearly identical. The FR701 has just a slightly looser weave and is fire resistant IIRC.

 

[bpape]

Not saying at all not to use the cotton. Just pointing out the difference in density vs usage.

 

[Rudy81]

Started out with a prototype for panels using 1/2" plywood for the sides and braces. My goal was to make the panels as light as possible, yet sturdy enough to hang vertically on walls and horizontally on a ceiling.

In terms of haning, I wanted to avoid having to purchase any major hanging hardware. I decided to try using french cleats, made on my table saw, as part of the bracing....thus incorporating the hanging system into the frame.

Overall, that worked out very well. BTW, best investment i made in terms of tools for this project, was a pneumatic stapler!

 

[Rudy81]

Not saying at all not to use the cotton. Just pointing out the difference in density vs usage.

The only density numbers I was able to find quoted 1.5 per cu. ft. for the R19. I could not find any numbers for the R30 I am using.

 

[Rudy81]

Next on the project list was to create a frame for a 4' long super chunk type of bass trap for the wall to ceiling corners at the main reflection points. Again, goal was to make a frame that was light and easy to hang. Used the same french cleat theory for hanging and that worked very well.

 

[Rudy81]

For the rear wall of my HT room (20'x27'x9'), I wanted to replace a poorly made quadratic diffuser. My original design was extremely heavy and I wanted to build something just a bit lighter and more presentable. I stumbled onto the designs at http://arqen.com/sound-diffusers/ and decided to build the basic diffuser panels. Again goal was to make them as light as possible and still meet the design.

Also came up with a french cleat hanging system which again worked very well.

The diffuser consists of 5 panels, each weighing in around 27 pounds. I chose to make them 4' tall.

 

[bpape]

Density would be the same. They've evidently beefed it up. Used to be about 0.8-0.9 lb/cu ft.

 

[Rudy81]

That pretty much covers the construction of the items I have put together thus far. I still plan on making some type of super chunk bass traps for the room corners, but am still deciding on how to best size the trap. I originally planned on a 23x23x32 triangular denim piece, stacked floor to ceiling. However, that size will force me to move all my curtains around and am not sure that is worthwhile. In looking at the test pieces I cut, I am wondering if rather than the standard triangular piece, I might go with a 12" square or similar size. Not sure if that would greatly affect the performance. I do want to maximize the bass control region for the room.

Before I post the REW results, let me mention my setup.

I have a 7.1 system with Oris horns as mains with DIY open baffle woofers and customized Klipsch RSW-15 subs for each main speaker....thus being able to privide 20hz-20kHz as close as I can on a DIY build. The side and rear effects speakers are Klipsch Cinema speakers. The LFE channel is made up of two tapped horn subs similar to the SPUD subwoofer.

Room size is 20x27x9 with two rows of seating. A DIY 120" Dalite High Power screen and HD projector.

The main speakers are all actively crossed and drivers all individually powered. I do have a house curve built into the Ashly crossover, so my graphs will show something less than a flat curve near the bass region.

I also use Audyssey Pro to calibrate the entire system.

I started by taking some bare room measurements prior to any treatments. I then added item groups one at a time and took readings to compare any changes. I warn you I am no expert on interpreting REW results, so any insight you guys can offer would be appreciated.

First up was to hang the rear wall super chunks. Then the rear wall diffuser. Followed by the side wall super chunks and diffuers. Finally, for this round, was to hang 4 panels as a cloud from the ceiling.

 

[Rudy81]

After hanging the rear wall super chunk and diffuser, here are the REW results. I am just posting a few items and have the original files, so if anyone wants to see some other results, let me know.

Readings were all taken from the listening position.

I suspect the rear diffuser will not make any big difference at the LP, but should be effective for folks sitting in the back row near the wall.

 

[Rudy81]

Rear wall treatment was followed by the side wall super chunks and side wall reflection point panels. I could clearly hear a big change in the echo that was present when running sweeps with just the bare room. I used an online calculator to get a rough estimate of the reflection point measurements and then backed them up with a large mirror.

 

[Rudy81]

The cloud I left for last since it took me a while to come up with an effective suspension system. I ended up using hooks screwed into the rafter joists along with strong zip ties to suspend the cloud.

As you can see in some of these plots, I still have to work on the bass region. I can produce plenty of bass, but the room dimensions do cause some cancellation in certain frequencies that I hope to tame with the corner super chunks.

Overall, I am confident that the work has been worthwhile, based on REW results but primarily by listening to my system in the 'new' room.