Our bluffer’s guide to acoustics continues with a step by step guide going through the physical process of building what you need to treat your studio…
Building an Absorber
1: Using 2 x 3in pine, make a frame that’s 1,199 x 650mm in size. Use screws to connect the timber together. Staple in some Cara fabric or attach a hardboard back. This will keep the Rockwool in place.
2: Turn the frame over and insert a 60mm-deep mineral wool fibre slab snugly within the frame. A tight fit will help the material to stay in position.
3: Cut enough Cara fabric to wrap around the front and to be stapled to the rear of the absorber. You may want to place tape over your staple heads to prevent marking on your walls. Alternatively, make a wooden frame to face the absorber. Use picture mounts to hang it.
Building a Bass Trap
1: We’re going to look at a corner broadband trap here. Take some timber – 12mm plywood is ideal – and cut two right-angle triangles (300 x 300 x 424mm). These will form the top and bottom of your trap. The backs will be 300mm by the height you can accommodate in your room.
2: Connect the parts together, either with screws or fixing blocks on the inside. Using a saw, cut Rockwool slabs into triangles slightly smaller that can stack up snugly inside the frame. These will provide a very deep absorber essentially, but work well for trapping bass and other frequencies.
3: Complete the corner trap by facing with Cara fabric or a perforated wooden panel of some description, ensuring it is acoustically transparent.
Building a Diffusor
1: Building a diffusor is perhaps the most difficult task presented here, partly because there’s a bit more maths involved, but also as it takes a little more skill in the workshop
The prettier of the two is perhaps the blockwork Quadratic (Skyline) Diffusor, but both varieties are pretty difficult. The best starting point is to download a diffusor calculator from the net and consider how it should perform.
2: Cut the blocks of wood into the appropriate lengths. Purchase some hardboard or 9mm MDF and cut to the required frame length to support the blocks. The next step is the tricky bit: arranging the blocks as per the grid provided by the calculator. As you arrange you’ll need to glue each block to the back and to any adjacent blocks it comes into contact with.
3: Leave the blocks to dry overnight (or longer, depending on the adhesive). Next, turn the whole diffusor over. Using a drill, pilot four holes through the rear hardboard to the longer lengths of block.
Screw together to aid adhesion. Make two holes through the ‘0’ sections (no blocks) in the sequence to connect the diffusor to the wall or ceiling.