Over the last couple months I’ve been putting up some acoustic treatment in the live room.
Based on measurements I have made in the past, I estimated that absorbers covering about 10% – 15% of the walls in the live room will bring the reverb time close to the ideal 500 ms.
I came up with a design that works with the layout of the room, ensuring absorbers were low enough behind the drums, but higher up behind the amps to each side.
Rather than use solid pine boards, which are often warped and irregular, I broke down two 8 ft. x 4 ft. 23/32 in. thick hardwood plywood, creating extremely uniform parts.
The first step was to start building the frames.
The frames are 3-1/2 in. deep, with corner braces inset 2 in., providing a 1-1/2 in. air space. They’ll be mounted about 1/2 in. away from the wall, giving the 2 in. absorber material about 2 in. of total air gap.
I glued the mitered corners, used staples to hold them tight while the glue dried and screwed in corner braces to add some reinforcement and hold the insulation in place.
The metal brackets are on the absorber side, so they’ll be hidden and out of the way when upholstering.
I then added cross members to ensure the frames don’t bend out of shape when mounted horizontally.
I used 2 in. Owens Corning 703 rigid insulation, which is very effective at mid and high frequency absorption.
I wrapped the back and adjacent sides of the fiberglass insulation with an upholstery backing fabric to keep the fibers contained.
The insulation material is so rigid that it actually gives the frames significant shear strength.
I now had all 12 panels ready to upholster.
I used a heavy duty synthetic felt material because it was more affordable, easier to work with and less prone to wrinkling than woven fabrics.
I pre-cut pieces of felt fabric, then wrapped, trimmed and stapled the fabric over the front and adjacent sides of each panel.
The Block on the wall and the French cleat double as a spacer, providing a stable air gap at the top.
The design for the mounting system uses French cleats, one attached to a block on the wall, the other attached to a block on the panel.
I used a flat black paint, which dries fast but more importantly provides a non-reflective surface that keeps these parts well hidden.
Just in case the blocks were visible at some odd angle, I painted them black.
The French cleat is attached to the panel blocks with 1-1/4 in. #8 truss screws.
Then I screwed one side of the French cleat to the panel blocks.
I pre-drilled holes in the wall blocks a bit oversized for the 1/4-20 wide-head machine screws they’ll be mounted with, allowing a minor amount of adjustment during mounting.
And then screwed the other side of the French cleat to the wall blocks.
Because 8 of the 12 panels will be mounted horizontally, I had to make 20 mounting block assemblies in total.
I also made some smaller blocks to use as spacers to make an even air gap behind the panels.
I used slotted metal brackets to attach them, so they can be adjusted if needed.
I covered the spacer blocks in the same fabric to ensure they don’t damage or vibrate against the walls.
The French cleats are rated for 60 lbs each, which is especially overkill on a horizontally mounted panel.
For the horizontally mounted panels, I used a set of two French cleats and spacers.
I covered the backs of the wall blocks with black contact paper to avoid the blocks adhering to the paint on the walls.
I laid everything out with a laser level and a laser distance measuring tool, double checking with a tape measure.
The panels on this wall are the most likely to get bumped as people walk by, so I’m hoping the mounting blocks and the wall anchors used to hang them will hold up under that stress.
Absorption was immediately noticeable while sitting at the drums after hanging the first four panels.
Each wall block is hung using two toggle-style drywall anchors, each rated for about 300 lbs in the 5/8 in. drywall.
The French cleats allow some horizontal adjustment, but once interlocked do not allow the panels to move.
The LED par cans and spots on the lighting grid give the space a totally different feel.
I like how the layout of the panels breaks up the walls a bit visually, and it certainly sounds much better, but it was time to take some measurements.
This measurement was taken at the guitar position, and most positions have very similar resonance times, but the sub-200hz bump in decay time is even more pronounced when at the drums.
And the verdict is, I still need bass traps in the corners, but the decay in the room is now extremely even above 200hz, sitting right at the idea 500ms.
Trevor Parscal's Studio 
