Unless your home studio was specifically designed for recording and mixing music, it’s probably not an ideal tracking and monitoring environment. Professional studios are carefully planned out to eliminate acoustic issues in many ways that residences are not. But if you’re up for a little DIY project, you can learn how to make acoustic panels which will absorb many of the problematic reflections plaguing your home studio! We also have a tutorial on making DIY bass traps you can check out when your done!
Acoustic issues in your room
Standing waves are produced when a wall’s dimension is equal to, or a multiple of, the wavelength of a particular frequency. They occur when sound waves bounce between parallel surfaces, such as between opposite walls and between the floor and ceiling.
Standing waves are a form of interference. As reflected waves collide with the original sound source, they can either combine or cancel each other out. This is referred to as constructive and destructive interference, respectively. The result of constructive interference is an unnaturally loud frequency, while the opposite is true of destructive interference. This typically occurs in the low end with frequencies around 300 Hz and below–those with longer wavelengths.
Such interference can create an inaccurate representation of the low end material in a mix. If your room has a constructive standing wave at, say, 100 Hz, you may compensate by carving out that particular frequency in the mix. When played in a different environment, your mix may be too thin.
Early reflections are those sounds first reaching our ears after bouncing off of a single surface in our listening environment. Psychoacoustically, our brain quickly determines the level and directionality of a sound source.
Combining with the direct sound leaving our speakers, early reflections can alter our perception of where a sound is placed in the stereo field and how loud it is.
Just as with standing waves, early reflections at higher frequencies can move through cycles of constructive and destructive interference with the direct sound. The result is a phenomenon known as comb filtering – a frequency response with sharp peaks and dips resembling a fine-tooth comb.
Comb filtering makes recordings sound thin and phase-y, and it can lead to making odd mixing choices that don’t accurately represent the source material.
How to Make Acoustic Panels: Absorption
Acoustic absorption is used to tame the mids and highs in a given environment. This is the most common type of acoustic treatment and should be the primary focus of treating your home studio for the first time.
You’ll want to use absorption to treat the early reflection points in your room:
- Behind your monitors
- On each side wall nearest the monitors
- The ceiling above your monitors
- On the wall behind your monitors
Finding the early reflection points in your room is simple. The trick is running a mirror along the wall and placing an absorptive panel where a monitor is reflected in the mirror.
A fairly common size for absorbers is 2 feet wide, 4 feet long, and between 2 and 4 inches deep — dimensions that work great for the average bedroom. Keep these measurements in mind and decide how many panels you’d like to build. For the early reflection points, 6 will do; the ‘cloud’ on the ceiling can be slightly larger at around 3 x 5 feet, but the build process is the same.
Basic acoustic panel materials and construction
- 1″ x 4″ lumber
- Owens Corning 703 rigid fiberglass, or Rockwool Rockboard 80, or R13 denim insulation
- Picture wire and picture hooks for hanging
Rigid fiberglass is the most common internal material for making absorbers. However, it’s a potentially dangerous hassle to work with. This especially true if you don’t take the right precautions beforehand, like wearing a mask and eye protection, long sleeves, and gloves. A great alternative to rigid fiberglass is denim insulation, which is incredibly absorptive and completely safe to work with!
Now you’re ready to measure and cut your wood to size for the external frame. You can attach the frame with wood screws or small nails — this is a simple rectangle which will hold the denim insulation.
Next, you’re ready to add fabric to the front of the panel. Simply stretch enough around the front and staple the excess around the outer edge of the back of the frame. Make sure the fabric is tight across the front; it’s what will secure the denim insulation and prevent it from falling out.
Start stuffing denim insulation into the back of the panel. It comes in a large roll approximately 3-4″ thick, so you will need to cut it to the width of the panel. Luckily, it’s safe and easy to work and won’t pose any of the problems rigid fiberglass does. Once you’ve filled the panel with insulation, you can cut any spare lumber you have into small pieces to be attached to each corner of the backside of the frame. This will keep the insulation from popping out of the back.
Finally, you can stretch a length of picture wire across the back of the frame with a bit of slack in it for hanging. Staple the picture wire down into the back of the frame. When you’re sure of where you want to place each panel, simply hammer in the picture hooks and hang your absorbers off them!
Conclusion: DIY Acoustic Panels
This is one of the simplest ways to build a DIY absorber. Learning how to make acoustic panels might be challenging if you’ve never built anything like them before, but this is one of the easiest ways to achieve moderate acoustic treatment in your home studio!