In all seriousness, I'd love to see peoples DIY room acoustic treatments. Please share whatever you can. How you built them, the materials, cost estimates, and measurements. I'd love to share lots of the free resources I've come to use in designing and implementing room acoustic treatments.
Please also share your subjective impressions of the improvement. Was it all good? Did it make anything worse? Anything you would do differently next time.
Coming soon from me:
-4.5" 6lb density acoustic panels made with Rockwool from Menards and 7oz canvass (light weight canvas is fairly breathable and acoustically transparent. I wouldn't necessarily use it as speaker cloth, but it is fine for acoustic panels.
-24" Bass trap using the same 6lb rockwool and a few little tricks for maximum LF absorption.
I’m attaching photos of my acoustic treatments. There is a plastic film membrane on that large square treatment with the blue jeans insulation. Also a similar treatment in the lining of the bass trap was done. Those pictures were during dry fitting. Sorry I need to learn to document my builds better, I was covered in saw dust, glue, and Rockwool so pictures were last on my mind.
Bass trap is wrapped in Black fine burlap. I paid just a dollar a yard or so.
The navy blue panels look really pretty in person and were made with 4” 1x4 select pine frames. I encreases the depth by adding slats across the back for mounting. With mount the panel is effectively 5” deep. It’s wrap in 7oz breathable canvas which is great for acoustic panels, since it stretches.
By the way I think that thick heavy canvass would be great for making a range limited acoustic panel with enhanced LF absorption.
new guy on the block . . . still getting to the intro page -for the time being however . .
2 free standing broadband panels, 28ish by 48, 2" 703 infront of 3" roxul, wrapped for fiber control and then an esthetic "look". this is for placement as 1st reflection points for the klipsch rb-51's as l/r in my man cave as the mirrors on the wall, behind heavy curtains, won't take nails very well..
new guy on the block . . . still getting to the intro page -for the time being however . .
2 free standing broadband panels, 28ish by 48, 2" 703 infront of 3" roxul, wrapped for fiber control and then an esthetic "look". this is for placement as 1st reflection points for the klipsch rb-51's as l/r in my man cave as the mirrors on the wall, behind heavy curtains, won't take nails very well..
I built these over 15 years ago..
They are made up of 3 separate timber frame sections within the outer frame..
The covering is polyester stretch cloth and each section is filled with 50mm. thick Ultratel (OC75 equivalent) semi rigid fibreglass..
They hang 50mm. away from the wall on French cleats..
The panel are 1600 high x 600 wide
They now have diffusers added..
I built these over 15 years ago..
They are made up of 3 separate timber frame sections within the outer frame..
The covering is polyester stretch cloth and each section is filled with 50mm. thick Ultratel (OC75 equivalent) semi rigid fibreglass..
They hang 50mm. away from the wall on French cleats..
The panel are 1600 high x 600 wide
They now have diffusers added..
These look great too. You guys are putting me to shame.
Are those barrel diffusers something you made or a purchased item?
One of my favorite Diffuser designers has recently taken a hard stance on what is and is not a diffuser. He won't let me call those diffusers anymore. They are re-directors
The surface of my sidewall reflectors is curved but I didn't make them. They are 2-3" foam cutbwothbthe curve and the surface has a patterned membrane and fabric. Behind them is another 3.5" of insulation that was stuffed down to about 3" or so. The concept of the original panel was to absorb at low and mid frequencies and diffuse or (redirect) at high frequencies where most panels become reflective. The original panel was a vicoustic panel and I removed the fabric and added a binary perforated membrane made of a thin plastic. It didn't absorb enough at upper bass frequencies so I built that frame to deepen it and add more insulation to absorb lower. The change in RT60 was dramatic.
However the quality of my craftsmanship was just ok. It was an experiment and looks like it. I should really redo it so it looks nice.
Lol!..love the name..
They are actually parabolic diffusers..I made them myself using 3mm MDF..Very simple to make..you just have to get the right curvature and then fit it into a frame..
There is no insulation stuffed into them, just the fibreglass panels behind..
What I noticed when I first used them was that the sound had widened dramatically across the sound stage..and in my new theatre you would swear that the sound was coming from outside!
I plan to work on diffussers once I have some time with the hope of widening the stage. It already sounds larger than the actual speakers but I'm curious what "true" QRD diffusers would do here. I had planned to build a full Stepped diffusser array but it's too wide to fit onto my wall without building around my lights. The plan right now is an 8" deep QRD diffusser that is roughly 60" wide and 50" tall. Exact dimensions will depend on the final design of course. I really want to try a high prime panel.
I'll probably post a build thread when I do this. I need to get some more clamps and a Brad nailer to make this doable.
Anyway I hope people can keep posting I want to see more. I need to build panels for Axpona and you guys are giving me some ideas.
Maybe Axpona can be my excuse to build the diffussers too!
Nice looking stuff guys... all of it's very impressive. I'm going to venture into these waters, despite submitting to the fact that you're probably way more hardcore (and technically inclined) when it comes to absorption/diffusion than I am. But, I'm okay with that. We all have our interests and areas that we prefer to dive deep in. Right?
At any rate, here are the traps and a combo rear wall diffusor/absorption panel I made DIY roughly...wow... about 8 years ago, I think? Matt, your technical side will probably cringe, but I followed general principles for placement and that's the way it will remain (although...I'm starting to think about building an addition onto my home with a new HT room...so, that could change... but general principles suit me fine ).
With the help of someone that knows a bit more about this stuff than I do, I created four corner traps that are 54" tall and 24" wide - 8" thick 705 insulation, one corner trap that is 33" X 24" - 8" thick 705 insulation, and one wall mounted trap that is 48"X24" - 4 inch thick 703 insulation... along with this weird binary slat diffusor combo designed to go over a set of windows (yikes!) present in the back of the room.
I know that there are minimalists out there that don't believe in heavy framing for their traps. From a performance standpoint, the less frame the better... and from a cost/time standpoint they are DEFINITELY WAY EASIER TO MAKE! But, I wanted something that was going to look good without sacrificing too much performance... so I spent quite a bit of time and money making frames.
My supplies are fairly straight forward. I found a distributor in Maryland that sold JohnsManville 703 insulation board and Knauf Ecose 705 insulation board. The primary wood I used was Pine #1 (I did use Pine #2 for the base of the frames and for the sides that aren't visible). If you ever plan on using/staining this kind of wood, plan on many MANY many hours of sanding and prepping the wood. Otherwise, your efforts will be for not. For the slat diffuser I purchased furring strips. And, of course, loaded up on tons of other supplies, countersink drill bits, screws, block sanders, stapes, brad nails, wood glue, Sand paper and stain and material (Cloth) and finishing strips. In terms of tools, I relied heavily on: a drill (with a 3 1/2" hole saw bit), a power miter saw, an orbital sander, a jig saw, a Dremel (sanding and wood removal attachments), a pneumatic nail gun (both finish nailer and brad nailer), a staple gun, and a cabinet making Bessy Clamps. Honestly, making these without those core tools would be almost impossible.
For the cloth, I purchased "utility speaker cloth," burlap, and quilting cloth (which is nice because it is relatively thin like muslin BUT comes in lengths of 108" and can be purchased in a multitude of colors).
For the bass trap frames, I opted to drill 3"+ holes into the framing. For those of you interested in doing this... there are several things you should know. First off... you need a solid drill with a ton torque. A cheap cordless drill will suffer and a low amp will flame out and die (believe me, it happened to me)... I suggest a good 9 amp or better drill. Secondly, the drill and the hole saw bit make a nice hole, but they are rough on the wood and the resulting holes require a lot of sanding (note, MDF board might not have this problem. I chose pine, though, because I wasn't comfortable using MDF due to some of its carcinogenic properties... especially when it is airborne with dust particles... also I've read it can smoke and release fumes when heavily drilled). I used various dremel sanding bits and then leaned on a randomly orbiting sander to finish off the smoothing of the outer rim of each hole. Talk about time consuming (and very tedious work!). If you're wondering how many holes I drilled... this board says it all:
Here's some trap build photos:
And here's some the diffusor/absorption build photos. I made the frame (note, instead of wood screws I used heavier hex-bolts)... then stretched material over furring strips that I brad nailed to the inside of the frame. Once installed, the material was placed in such away that it gave me about 2 1/4" of space on the backside (room for insulation) and about 3/4" space on the front for the slats and finishing touches. On the backside of the material, I installed two 2 1/2" thick furring strips (notched to fit around the firing strips holding the material) horizontally... spaced about 2 feet apart. I don't have a photo of them... but they were installed to help hold the insulation AND to give me a place to nail the slats in the middle. In terms of sequencing for the slats, I used a binary sequence.
The furring strips holding the material and the two larger firing strips running horizontally across the mid section of the frame gave me 4 solid points attach the slats with a brad nailer. Adding 703 insulation in the back (behind the material) was straight forward. It bulges just enough to touch the backside of the slats.
This gives you an idea of what it looks like. This is hanging from the ceiling about 3 1/2 feet behind the primary seating position. I still need to build my AV Showcase, so I'll take some other images soon.
The hole saw work - gotta be true love. MDF will kill an expensive hole saw in no time . . lowers the ROI and is really messy
When I built some of my other clouds I used the same partially open sides framing as in my first post. Actually calculated the "added advantage" of more exposed area for broadband panels. seemed like a better ROI per sq. inch for the time opposed to endless drilling.
I used sheer curtain voile as a fiber wrap /trap before a cover warp, which is many cases is just another layer of the same. My ceiling front clouds , ( 3 of 3' x 4', 1 of 18" x 4') total 42 sg. ft are spaced across the 12' dimension with about 5-6 inches between the edges -more exposed area, and also hanging down from the ceiling about 5", so that's the same surface area again.
I have some build pics on a different computer.
The "re-directors" . Now that's an idea I'd like to hear more about.
The hole saw work - gotta be true love. MDF will kill an expensive hole saw in no time . . lowers the ROI and is really messy
When I built some of my other clouds I used the same partially open sides framing as in my first post. Actually calculated the "added advantage" of more exposed area for broadband panels. seemed like a better ROI per sq. inch for the time opposed to endless drilling.
I used sheer curtain voile as a fiber wrap /trap before a cover warp, which is many cases is just another layer of the same. My ceiling front clouds , ( 3 of 3' x 4', 1 of 18" x 4') total 42 sg. ft are spaced across the 12' dimension with about 5-6 inches between the edges -more exposed area, and also hanging down from the ceiling about 5", so that's the same surface area again.
I have some build pics on a different computer.
The "re-directors" . Now that's an idea I'd like to hear more about.
Nothing really to the term. It's a way of using more precise language to describe the different kinds of acoustic devices we use.
As we all know sound will do a few things whenever it hits any surface. It will either reflect, absorb, or pass through. That's all it can do. It can and will do all of these things typically and it won't do them evenly at all frequencies.
When sound reflects it can either reflect all of the sound in one direction, the incident angle, or in multiple directions (usually a set of incident angles depending on the precise geometry of the surface it hits). When it "scatters" it can do so in a predicable uniform manner or it can do so in a random manner. Random is diffussion, uniform is scattering. If in fact it largely sends all sound that hits from a particular angle off in a different direction, a function of the incident angle of the sound wave hitting the surface, then we are really redirecting the sound in a different direction than it would have gone with a flat surface. This is done insurance studio clouds all the time.to reflect the ceiling reflection past the soundboard and into the rear diffuser or absorber.
Obvious re-directors would be any kind of flat surface placed at a particular angle to the wall. Less obvious re-directors are pyramids, barrels, waves (to some extent at least), etc. These devices don't provide a lot of scattering and minimal diffussion, they largely redirect the sound away from the listener. A wave may not be a re-director, more of a 1D scattering diffuser if the wave pattern is non-periodic and complex.
I once helped design a lobby area using a complex surface sculpture to help redirect sound toward wall absorbers. It was a very large fully reflective lobby area of a hotel. The sculpture came from a local artist who designed it with my and the architects input on a computer program to create curving surfaces that would largely help either scatter sound, diffuse sound, or reflect it toward the wall. This idea is very common in large Architectual acoustics. You would be amazed how much science might be behind those funky sculptures in the lobby of a building you enter to make the sound tolerable.
To be truthful, drilling those holes was not only extremely time consuming... but also downright dangerous. Any snag practically tore my arm off. The smart way is to get a drill press. I didn’t have access to one.
I’m not sure I’d go the whole DIY route in that manner again. At least not now. Way too little time for stuff like that. Fun tho!
To be truthful, drilling those holes was not only extremely time consuming... but also downright dangerous. Any snag practically tore my arm off. The smart way is to get a drill press. I didn’t have access to one.
I’m not sure I’d go the whole DIY route in that manner again. At least not now. Way too little time for stuff like that. Fun tho!
It's true and you don't save a ton of money either until you get into big stuff like bass traps.
With bass traps you do save money but you don't have any gaurantee on performance. I've had very mixed luck on Diy bass traps. Because of that, as of right now, when I bid on a job I always include panels from ASC or Gik. I have to be able to prove to a client they work. Just to give you an idea about how serious this is, when I went to my insurance company after forming the official company, I was told that acoustics is a high risk for litigation field and I needed different expensive insurance. My overhead is so high because of this I have to add add it as a seperate line item to show my hourly is reasonable.
Well maybe not a true cloud in that it doesn't float below the ceiling but my ceiling treatment is glued directly to the ceiling. A mix of silicone adhesive and highs bond tape.
If I get a chance to see you in person Todd I can share more detailed photos. Have a few of client jobs but I always tell them I won't share photos. As you can imagine, since I don't do studios clouds aren't common for me.
My cloud mounting technique uses rails and hooks. Chain or cord to suspend it. Sometimes wooden cleats if I need a low profile. Glue if I need the lowest profile.
Very nice work Todd..
One of the advantages of having an AT screen is that you can hide a lot of stuff behind it out of sight.!
My front bass traps consist of 3 layers of 50mm. Ultratel..floor to ceiling 450mm. wide across the corners and covered in black cloth..
No framing needed and it looks as rough as bags!!
Very nice work Todd..
One of the advantages of having an AT screen is that you can hide a lot of stuff behind it out of sight.!
My front bass traps consist of 3 layers of 50mm. Ultratel..floor to ceiling 450mm. wide across the corners and covered in black cloth..
No framing needed and it looks as rough as bags!!
Hah you should see whats behind my acoustically transparent front stage. I made it so the entire front of the room from the front wall out 30" is completely covered walls, floor, and ceiling with insulation. The Insulation is 2" thick Linacoustic and I did two layers where I could. There is 450 square feet of acoustic insulation just on the front wall area behind the screen alone. On the right front corner I threw all the scraps of insulation I had from the panel projects, then placed 4" thick 8lb density rockwool insulation in front of them and covered it with a wool moving blanket. I plan to change that out I just did it temporarily.
Then I took all the acoustically transparent panels on the screen wall (Not the screen, just the trim panels around it) and lined their backs with the Blue jeans insulation, 3.5" thick (It sticks out the back of the panels). The Floor panel below the screen, alone, is 8 feet wide and 24" tall of 3.5" thick insulation. It's all very ugly, not very professional looking, but nobody can see it.
Yeah, they look better than my hack work anyway. I'm getting better, some of mine I could sell for sure, but nothing is as good as professional products for the most part. They just have equipment we often don't have for making them look nice.
The only reason I wish I could use my own panels without issue is special needs. I usually have to commission a special panel from someone like ASC, which is really expensive.
For example, let's say its a home theater or studio or some other sound room with a very specific and prominent modal distortion. Maybe at like 45hz. Then I probably will need to go to a tuned trap in that special circumstance. Getting a trap tuned at exactly the right frequency is important and difficult. Sure its ok to be off a few hz, but if its 5hz or more, that is too much below 100hz. Especially important in performance spaces where you can't use EQ because you can't EQ a live instrument. It's only come up once for me so far (I don't do a lot of jobs), but it's a real issue. I noticed a lot of bigger and more established acoustics folks just don't bother fixing it, they just use a ton of broadband absorbers, which I don't think is the right solution.
Then take a job I bid for a few months ago (They haven't accepted it yet so I don't know that I will be doing this). They have a large parabolic dish over a conference table. It is taking all the sound of the voices coming up from the conference table and focusing it in this dish and basically beaming it back down on the individuals causing terrible speech intelligibility. The echos are very short, normal measurements don't even really depict the real problem. I can't cover the dish in insulation, that would be ugly. I have to find a way to break up, redirect, and absorb some of these reflections, and it has to look modern, artistic, aesthetically pleasing. That's a tough fix, so my solution is to use a grid diffuser array around the table with a mix of lantern absorbers (imagine a hunk of insulation in the shape of a Chinese lantern) hanging at different heights throughout the domed ceiling. There is only one major supplier of these lanterns, they are pretty expensive for what they are, and I'm limited to their fabrics, which aren't best for this company. Good fix though right? The other bidders (from what I was told) had standard fixes of just panels on the walls, which wouldn't fix the problem.
Yes all of it. There is a membrane between the speakers to provide more reflections and greater bass absorption but mostly it's all absorption. Not just the front wall. The front portion of the side walls and ceiling too. There are a lot of good reasons to do this that are too much to explain here.
On the right front corner I threw all the scraps of insulation I had from the panel projects, then placed 4" thick 8lb density rockwool insulation in front of them and covered it with a wool moving blanket. I plan to change that out I just did it temporarily.
can't say how or if this relates to your parabolic ceiling reflector fix " just turn it over" (?) but I was intrigued by the possibilities of this device in the library . . as a "redirector" -LOL
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and that's the way it will remain (although...I'm starting to think about building an addition onto my home with a new HT room...so, that could change... but general principles suit me fine 
).
