(More) Big progress on absorption panels

[b1j]

Yesterday evening on the way home I stopped in to Joann Fabric and walked out with a bolt of simple cotton muslin:

https://www.joann.com/sew-essentials...n/7791601.html

In every article I’ve read or YouTube video I’ve watched in the past year as I geared up to make my absorption panels, and in every piece of advice about this or that part of the build, nobody has ever recommended muslin to cover the insulation. But it passes the breathe test! And one bolt is exactly the amount I need, and the width is ideal, which will minimize cutting steps. Is it so wrong that it’s not Guilford of Maine at ten times the price with lots of waste? I really feel like I’m veering off into my own personal uncharted waters, but I haven’t found a downside.

So, first question: is muslin somehow ill advised? I’m planning to use it for both the front and back cover. Am I missing something important?

I’m following the design of Michael Wynn’s “In the Mix” YouTube build video:

https://youtu.be/HO7aeraKLsM

Today I made the first inner frame, and now it’s ready to staple the backing fabric into. Then it’s pop in a Rockwool sheet, flip it over and gift-wrap/staple the front cover onto the frame, and finally build and attach the 1 x 4 pine outer frame. I’ll add side handles and detachable hinges to let me set up pairs of panels as free standing “books.”

I’ll try to get the first panel done this weekend. What’s left is mostly fabric cutting and stapling and a little minor woodwork. Then I’ll try to refine and streamline my process based on what I’ve learned. Already I can see I might want to get my jointer in the act to remove very minor twist in the frame members. Frames can be tricky to get flat.

Anyway, what a relief it is to move out of the protracted design phase and into production. Please yank me back into common sense if I’m making a terrible mistake with the muslin.

[keith.rogers]

Muslin is fine. I’m sure I read somewhere it was a good material, and I have it on about half the panels in my room. The rest were remnants I found that were even cheaper - giving the room an “eclectic” look that distresses my better half, but I saved money !

p.s. I just snapped a blurry pic of the room (kind of a mess as we are beta-testing the downsize concept and I've collapsed much of "the office" into my music space). I have 7/16 of the panels covered in muslin, though given the gobos are 2x wide, it's actually about 9/16 by area. I even have other material on top of that in some cases - If it's not waterproof with plastic or vinyl, I think most fabrics will do, but, of course, an open weave that resists tearing easily is going to work best IME.

[rick-slo]

https://www.boomboxpost.com/blog/201...ur-home-studio

[b1j]

Originally Posted by keith.rogers

Muslin is fine. I’m sure I read somewhere it was a good material, and I have it on about half the panels in my room. The rest were remnants I found that were even cheaper - giving the room an “eclectic” look that distresses my better half, but I saved money !

p.s. I just snapped a blurry pic of the room (kind of a mess as we are beta-testing the downsize concept and I've collapsed much of "the office" into my music space). I have 7/16 of the panels covered in muslin, though given the gobos are 2x wide, it's actually about 9/16 by area. I even have other material on top of that in some cases - If it's not waterproof with plastic or vinyl, I think most fabrics will do, but, of course, an open weave that resists tearing easily is going to work best IME.

Looks great. I was under strict proactive orders not to distress my artist in residence. I was to use earth tones, no blue, red, or green. If anything, I may have carried the cost savings too far: I bought bleached muslin, not even the tea color that would have been twice the price. But the other reason was that the tea was the wrong width and would have created waste and required much more cutting.

Did you make your corner traps, too? What do they have for insulation material?

[b1j]

Originally Posted by rick-slo

https://www.boomboxpost.com/blog/201...ur-home-studio

Thank, Rick. That’s a very thoughtful article by an obviously experienced person. It’s making me think about the tear resistance of muslin around the staples. I’m going to proceed with muslin anyway, at least in my pilot panel, so I’ll pull and stretch carefully.

Two elements of my panels ease my mind somewhat about muslin’s delicacy. One is that I’ll have an outer frame of wood around the wrapped muslin, so that will lower the risk of scuffing and wearing out the fabric at the edges. I chose this because I want the panels to serve as moveable gobos as well as wall hangings. The other is that I’ve rounded and smoothed the edges of the inner frame that will come into tight contact with the fabric. The blogger added a step with batting. That seems cumbersome, and if I read the build sequence correctly, she has the batting covering not just the frame’s edges but also the entire 2’ x 4’ back area. Would this be acoustically transparent?

Speaking of acoustically transparent, what’s with the 1-1/4” MDF covering the back of the panel? From what I’ve read, that would defeat the purpose of using transparent materials (not to mention probably more than double the weight). MDF would be an excellent reflection material, and we’re looking for absorption (two-way absorption if you add a rear gap).

I suspect she depends on the rigid MDF to stabilize the rectangular shape of the wood frame, which would otherwise easily deform — rectangles are not stable like triangles — and like many DIY advisors she uses screws into end grain of the long sides (not durable). My frame (Michael Wynn’s design) seeks to achieve rigidity from the 1” x 2” back of the inner frame. I cut clean, square ends on the (three, my adaptation) lateral members, and joined them to the long sides with pocket-hole (Kreg) joinery. I’m sure I could shove them out of square, but I’ll remember to handle them carefully when I move them around. One long side of each panel will have a handle in the middle at the center brace.

We’ll see. Wish me luck today.

[rick-slo]

I have a couple of dozen or so ATS panel hanging on my walls and ceiling.

You may find their FAQ page a useful read:
https://www.atsacoustics.com/page--A...FAQs--faq.html

[keith.rogers]

Originally Posted by b1j

Did you make your corner traps, too? What do they have for insulation material?

All homemade - just used double the thickness of Safe’n’Sound with an air gap so they filled the 1x8 framing.

Yeh, I went with the “better to ask forgiveness…” mode of construction, which, technically I never got; but it’s upstairs, out of the way and has a door that remains shut, so detente was achieved .

[Chipotle]

I've used muslin on the back of panels, but no reason it won't work for the front too. As long as the air can pass through but insulation fibers can't, it's good.

When stapling the muslin, I just folded over the edge to double the amount of fabric I was stapling through.

And for panel rigidity, I cut small triangles from leftover bits of wood from the frame, and screwed/glued them into the inside corners of the rectangle. Easy, and I already had the materials.

[KevWind]

Originally Posted by Chipotle

And for panel rigidity, I cut small triangles from leftover bits of wood from the frame, and screwed/glued them into the inside corners of the rectangle. Easy, and I already had the materials.

Yep me also instead of an entire inner frame as in the OP video. I just made corner braces and then the center of long side cross bracing -- all made out of 1x4 pine (drawing shows back of panel)

[keith.rogers]

I never had a problem with mine going out of square, but I'm not moving them much, and I only had the 15.5" wide rockwool to work with. Plus, and probably importantly, I had a good, power miter saw for cutting the lengths, so the cornter butt-joints were square. I used "baling wire" stapled in to the sides to lightly hold the material in the frame.

[b1j]

Originally Posted by keith.rogers

I never had a problem with mine going out of square, but I'm not moving them much, and I only had the 15.5" wide rockwool to work with. Plus, and probably importantly, I had a good, power miter saw for cutting the lengths, so the cornter butt-joints were square. I used "baling wire" stapled in to the sides to lightly hold the material in the frame.

The diagonal wires will take care of square, alright. Dumb question, but did you cover the panels with fabric? (I told you it was a dumb question.)

[keith.rogers]

Originally Posted by b1j

The diagonal wires will take care of square, alright. Dumb question, but did you cover the panels with fabric? (I told you it was a dumb question.)

The wire was because I didn’t know if the “stuffing” would sag over time and I knew some might end up on the ceiling. It’s probably unnecessary for wall mounted panels. Having truly square cuts at the corners makes life a lot easier.

The fabric(s), shown in post #2, was wrapped and stapled in the back, which was covered with that black fabric you see in the bottoms of chairs and such. Could have used muslin for that, too, of course.

[b1j]

Super dumb question! I didn’t connect the name.

Anyway, these are good looking panels. How would you describe the acoustic improvisation these have made in your room?

[keith.rogers]

Originally Posted by b1j

Anyway, these are good looking panels. How would you describe the acoustic improvisation these have made in your room?

The first impact I noticed was that I found that the mixes translated much better, and I'd say that has a lot to do with really removing the room from what I was hearing. I mostly just covered early reflection points and did front-back traps with bass traps in 3/4 corners. (Untreated, it's a *terrible* room, 11'x11'x8', and even fairly well treated it's never going to be more than adequate, but I'm Ok with that, and, for some years now, it's been mine .)

And, I should comment that I originally did the trapping to address the monitoring situation for mixing things recorded elsewhere. It turned out to be pretty decent for recording, and during the shutdown I got to experiment [more] with recording.

[b1j]

Thanks for understanding that I meant “improvements” instead of that hasty autocorrect.

I’m excited to bring eight 2x4x4” panels into my 12x13x8 room! I have a couple more corners to tuck on the pilot panel, and then will cover the sides with a 1x4 pine outer frame.