Winer Wood Panel Bass Trap on double frame wall ?

[bb33]

I am treating part of my garage for a live band room. This is an ongoing project, and I would like to share pics along the way. My 3 questions are at the end.

The live room has the following interior measurements: 27’ wide x 35’ long x 8’-6” tall. The floor is slab concrete. The walls are concrete block. The ceiling is 3/8" plywood, covering 2x10 wood joists centered 16” and filled with 10” yellow insulation. (acoustically, the ceiling measures 9’-4”?)

I am located in Coastal South Carolina, and like many coastal houses, mine sits on top of a tall concrete block foundation. This foundation elevates the house above the flood level. My foundation has numerous 4’x8’ openings, which allow catastrophic flood surge to flow beneath the house. The band/office area had 9 such openings”: 2 were filled in with double-doors (one opens out, one opens in); 3 were filled in with windows (bottom half is double plywood wall, top half is window); and 4 were filled in with double-wall pressure treated plywood. All doors, windows and walls have 2 separate 2x4 stud walls with 5/8” treated plywood, each filled with 3” of Safe & Sound. All have been caulked with OCI-SC175 acoustic caulk. All have insulated flood vents at the bottom. There are two 16”x16” solid concrete block columns. (see floor plan)

Our classic rock band has drums, bass, 2 guitars, keys and vocal pa. We are all late 50’s to 60’s. We have been playing in one of the other’s house, which has surprisingly poor acoustics. There is massive wash, which means we keep turning up the volume. The drummer hits pretty hard and we have to keep up, neighbor wasn’t happy, same old weary tale. We will move into my garage band room once I finish.

Unfortunately, I do not have a sound meter so I cannot provide accurate sound levels. Drums are loud but not deafening. Bass is a 1x12 practice amp. One guitar is a 1x12 and the other is 2x12. Vocal PA (broken) was 2 speakers with 1x10 + horn, but I will be getting two 10” Yamaha DBR10’s.

My goal is three-fold:
1) Treat with diy panels and traps such that we can play at lower volumes with clear instruments and vocals.
2) When we do turn it up, my happy neighbor will stay happy (his house is 75’ away).
3) GarageBand recording our band.

My acoustic treatment will be broken down into small projects. The first project will be 12 broadband panels. They will measure 24” x 48” x 6”. I will use 2x6 framing; 2 layers of 3” Safe & Sound, and wrap with 10 oz cotton duck (http://www.bigduckcanvas.com). I will hang these 4” from the walls at about head height.

The second project will be 4 floor-to-ceiling vertical corner traps. These will be 24” x 24” x 48” units built with 2x2 lumber and plywood top and bottom. I will fill them with either a) 8 columns of 3” thick Safe & Sound, or b) 2 columns of 12” thick low density pink insulation. They will be wrapped with 10 oz cotton duck cloth. If I feel ambitious at that time, I will build some to go in the horizontal wall/ceiling corners.

The third project will be 4 gobos. My plan for the gobos is subject to change, but for now is:
48” x 48” x 12” using 2x12 lumber for the walls and 3/4" mdf for the back wall. They will have either a) 2 layers of 3” Safe & Sound plus air space, or b) 1 layer of 12” low density pink insulation, and will be covered with 10 oz cotton duck. These will be used around the drums to absorb some of the 20-100Hz kick, 60-210 Hz toms, and 120-250Hz snare. I will likely build more in the future, but will start with 4. I may attach a layer or two of drywall on the inside next to the rear mdf panel to add density (thoughts?).

The fourth project will be 4 broadband clouds. The clouds will be 4’ x 4’ x 4”: a single layer of 3” Safe & Sound inside a 2x4 frame, covered with 10 oz cotton duck on the bottom and drywall on the top. I will hang these at a tilt a few inches from ceiling above the drummer and amps.

A later project will be the two 16”x16” columns. I may build some shelves, I may hang broadband or build 2’x8’ Winer bass traps, or may build diffusors, or use to hang guitars – not sure yet.

I save the bass panel absorber traps for last, although my first questions deal with them. My plan is to build 4 – 4’ x 8’ panel absorbers using a hybrid plan of BBC, Winer and Acoustic Fields:
2x12 frame.
3/4" mdf back; 2” air; 1/8” pegboard; 2 layers of 3” Safe & Sound; 1/8” pegboard; 2” air; 1/4" mdf front panel
(2 will use 1/4" and 2 will use 1/8”).
I am contemplating a layer or two of drywall on the inside, against the rear mdf panel, to add density.

These traps will be big and heavy, and I will connect the top to the wall for stability.

I will put 1 these monoliths on each wall, or group 2 on the end wall, or possibly all 4 on the end wall.

Now… back to 4 wall openings on the end wall that have been filled with double 2x4 walls with plywood.

Question 1: Could these be used as the rear panel of the bass trap system? It would be very convenient to build the shallow Winer system of 2 deep bass and 2 high bass directly onto these four 4x8 double walls, but here are my three concerns:
1) It would turn the currently double leaf wall into a triple leaf wall.
2) It would concentrate low frequency energy into the weak spot on that wall.
3) 4 (or 6) separate free standing 4’x8’x12” traps would provide some degree of isolation from that wall, remembering that the neighbor’s house is 75’ away (Unfortunately, code will not allow building a wall-within-a-wall due to flood, nor will it allow drywall. Also, I recognize that soundwaves will go around and through a freestanding “wall” of bass traps, but would they help noticeably?).

Question 2: would an additional layer of 3/4” plywood on either the inside or the outside or both of the double plywood wall make a noticeable difference for isolation (ie: the neighbor)?

Question 3: Does the orientation of the band make a difference to either the isolation or interior acoustics? One option is to situate the band in Area A, with our backs to the wall, and with the vocal PA situated in Area B facing towards us and towards the wall. Another option is to situate the band in Area B facing the wall, with the vocal PA situated in Area A facing away from the wall towards us.

Thank you very very much for your time and consideration! bb33

[John Sayers]

bb33, first thing I would do is seal the concrete blocks either by rendering them or at least painting them

cheers
john

[bb33]

John, thank you for reading my post, and for your suggestion to render or paint the interior concrete block. I have read about painting, and was surprised at how much a simple coat of paint contributes to isolation. I had planned on painting but unfortunately, I was told by the flood insurance company specifically NOT to paint the interior block because it changes the status of the room from "storage" to "living space" and adds tremendous cost to flood insurance.

I had to look up "render" : it is essentially a skim coat of cement. The exterior has a patterned coat of what we call "stucco" maybe 1/8" - 1/4" thick of cement. Hopefully that will help. Unfortunately, I think stuccoing the interior would be comparable to painting, as far as the flood insurance is concerned.

Question:

What about installing 4'x8' panel bass traps https://ethanwiner.com/BTPlans.gif directly on the interior sheet of 4'x8' plywood? It would likely help on the interior, but would it help or hurt isolation, ie sound getting to the neighbor's house 75' away?

[John Sayers]

yes, the bass panel absorbers will work. I would make them 4' x 4' (or even 2' x 2') so you can vary the thickness and the materials, i.e. plywood and mdf at differing thickness so it becomes broadband.
cheers
john

[bb33]

Thanks for your feedback, John. I really like the 4'x4' suggestion. I have 4 of the 4x8 double walls, so that gives me a total of 8 4'x4' sections, 4 on top and 4 on bottom.

How does this sound. . .

bottom:
2 deep-bass traps (1/4" front panel) (4'x4')
2 high-bass traps (1/8" front panel) (4'x4')

top:
2 mid-high absorbers (4'x4')
1 deep-bass trap (4'x4')
1 high-bass trap (4'x4')

Note: I am also going to put 24"x24" floor-to-ceiling corner traps (pink low density insulation) in both corners on that end wall - good idea?

[John Sayers]

Looks good, there is another variable and that's the depth, varying the depth will give you lower frequencies and diffusion as well.
Make some 4" deep and others 8" deep. or some 2" and 4" deep.

For the corner traps use high density, 3.0 pcf / 48kg/m3 insulation.

cheers
john