Don’t worry, it’s actually a great question. I’ve made multiple Home Studios and this is one thing that has made my songs sound better. I’ve researched this topic for years and have found that a lot of articles online are technical and hard to follow.
Acoustic Treatment is a complex issue but I’ve written this article from the perspective of us in the home studio world to give you practical information that you can apply to make your room sound better and ultimately make great sounding music.
In this article you will find:
Why should I use Acoustic Treatment?
Evaluating Your Room
Absorption
Diffusion
Bass Traps
Reflection Filters
Why should I use Acoustic Treatment?
There is a very simple answer to that question. We want to treat our rooms to get a balanced sounding room. We want this so we can record a variety of instruments as well as, mix accurately. Untreated rooms have weird frequencies that affect our mixing decisions. It is because the sound is changed by our room. That’s why, when we make mixing decisions in our room that we think sounds good, they end up sounding horrible in the car or on our phone. Untreated rooms also change how our instruments or voices sound. We have all the unwanted reflections of our room in the recording.
Using acoustic treatment helps us to lessen the chance of these unwanted frequencies and reflections from tampering with our sound. There are 4 major points in our rooms that we should focus on.
- Corners – wherever two walls meet is a place for standing waves to hang out and destroy our low end.
- Corners and Ceiling/Floor – where the corners meet the ceiling or floor is a favourite place for sound to congregate.
- Walls – the walls act as a sound reflector, which in a small studio is a bad thing. It causes some waves to cancel out and also sends sound waves to your mic at a different time than your direct sound coming from your instrument.
- Early Reflections – These are surfaces that are very close to the source that will reflect back and cause unwanted reverb.
So, knowing all this, where do we start? The first thing we want to do is test our room to find the problem areas that are specific to our space.
Evaluating Your Room
The first thing we want to do is find the spot where we are going to be doing the listening (for mixing) and for recording instruments. For most of us, the room is going to limit us to playing double duty, both mixing and live recording. That’s totally OK. Set your desk up on one end of your room so you are using the room length-wise. You want to give a foot or more space from the wall to the speakers. Make sure your speakers are equal distance from the wall on either side. When you have your desk set up and speakers in place, you can check to see where your Early Reflections will be. A little trick is to place a mirror on your desk while you are in the listening position and move it around until you can see the speaker in the mirror. That area will be an early reflection. Another trick for the ceiling is to get a friend to hold the mirror on the ceiling and move it around until you can see the speaker in the reflection, from your listening position. This will be your reflection point. Repeat the process on both walls on the side and you will have the area that is most important for you to treat. This will be your “Reflection Free Zone” as producer/ engineer Bobby Owsinski calls it.
We then need to find out how the room “sounds”. The simple way to do this is the “clap test”. Start from your listening position. Clap your hands and listen for the reverb. If you are in a beautiful 16th-century cathedral you will hear a very warm and pleasant reverb. But, most likely you are in the spare bedroom and you will hear some very metallic, unpleasant sounds. Determine the direction of those sounds and note the area for absorption materials. Move around the room repeating the clap test until you have a good idea of the problem areas. They will be as we described earlier.
There is an online tool that we have found to be helpful. You just need to enter your room dimensions and it will give you a Minimum and Recommended coverage in square feet. You can find it here. We have found in our research that the general rule of thumb is 25-30% of your room should be covered. But covered with what? There are three main types of solutions.
- Absorption
- Diffusion
- Bass Traps
Absorption
Absorption is an easy concept to understand. It is simply that when a sound wave hits the material it is no longer going to bounce around the room…it has been absorbed. Absorption will be the material that you use to control your listening position. Every area that we identified earlier should be covered with absorption panels of some sort.
There are 3 main types of material that are used for Absorption Panels:
- Acoustic Foam – can easily be purchased online and are relatively easy to install. They are good at absorbing mid to high frequencies only.
- Rockwool Insulation – panels made from Rockwool can be purchased ready-made online or there are a variety of DIY options available. Rockwool is a great broadband absorber that is capable of absorbing mid to high frequencies as well as most low frequencies
- Rigid Fiberglass Insulation – panels made from Owens Corning 703 (rigid fibreglass) can be purchased online or there are a variety of DIY options that are the same process as Rockwool. Like Rockwool, rigid fibreglass insulation is broadband and can take care of most unwanted frequencies.
Once you have set up some Absorption Panels in your target areas you will hear a noticeable difference when you perform the “clap test”. There are a few other options to take it to the next level.
Diffusion
Diffusors work by breaking up soundwaves in different directions so nothing gets trapped. They come in 1D or 2D configurations. 1D diffusers send the waves either left to right or up and down. 2D diffusers use a combination of both directions. They are used in combination with Absorption panels so that the room doesn’t feel so “dead” with the lack of reflections.
The downside to diffusers is that they can be quite expensive. There are some DIY solutions out there if you feel handy. It takes a lot of math and a tone of labour, but the result can be pretty cool. Here is a calculator for figuring out the math part. For those of us who are in Home Studios and on a limited budget, there is a simple solution that you probably already have on hand. Put a bookshelf on the back wall and fill it with books and other random things. This is a great diffuser and won’t really cost you anything.
Bass Traps
The biggest problem in small studios is controlling bass frequencies. As we talked about earlier, bass frequencies like to hang out in corners. So that is where we want to put our bass traps.
Bass traps come in two forms:
- Porous Absorbers – These absorbers are made of absorption materials like acoustic foam, Rockwool, or Rigid Fibreglass insulation. They are normally made extra thick to absorb low frequencies but because they are made from absorption material they are very effective across the frequency spectrum. There are also many DIY solutions available. The downfall to these is they cannot absorb the lowest frequencies below 80hz.
- Resonant Absorbers – These absorbers are made using a diaphragm that is tuned to resonate with specific low frequencies. They can effectively absorb even the lowest frequencies but do nothing to absorbing mid to high frequencies. They are more expensive than porous absorbers.
For most of us in the small Home Studio world, we will focus on porous absorbers. They are a cost-effective way of controlling low frequencies. Honestly, fill the corners with as much of this material as your budget will allow and you will be much happier with the sound of your room. When you get more money, put in more bass traps.
So you might be thinking to yourself, “this is a lot”. Is there anything you can do to start getting great music without doing all of this?
Reflection Filters
If you don’t have the budget yet to start into Acoustic Treatment you can start by buying a reflection filter. These are small, lightweight absorbers that fit onto a mic stand. They are designed to absorb the reflections while you are performing directly into the mic. They work by sitting right behind the mic with absorption coming around the sides, and they actually do a lot to reducing reflections. They are not a replacement for good acoustic treatment but they will provide a noticeable difference in isolating your audio prior to mixing.
One thing to take note of is that reflection filters cannot help you in mixing. They do not change the sound of your room so you will need to use a pair of good studio headphones in order to get an accurate mix. But it is a start.
The Bottom Line
Your room is a vital link in the chain of your musical expression as a music producer. After all, music is about sound and the more control you have over the sound the more you can shape it to what you want to express.
Think of your room as your instrument and think of absorbers, diffusers, bass traps, and placement as the components of your instrument. The more time and care you put into making it, the more you will get out of it.
