Acoustics 101
Wikipedia says acoustics refers to the science of production, control, transmission, reception, and effects of sound. For most recording engineers, the term acoustics refers to the sound of a room. If you’ve ever looked at most digital reverb processors, you’ve noticed that the patches are sometimes defined by room names (such as small room, bathroom, cathedral, or large hall). That’s because the sound of the room is mostly determined by its reverb, or the way it reflects sound. Some rooms have a lot of reflections, and some have very few. The important thing to understand is that every room has some sort of reflection.
Different types of recordings require different types of recording rooms. In a professional studio, the recording room is designed so that its reflections only enhance the acoustic sound. What makes a room sound good or bad can be different for different people. Often, the reason certain studios become popular is engineers find that a certain room in the studio sounds especially good for the type of recording they do. In these cases, the recording room itself becomes just as important as every other element in the recording chain.
If you’re recording in a home studio, chances are it’s a bedroom, basement, or garage. Each of these rooms can sound dramatically different for both recording and mixing. Several elements affect the way a room sounds acoustically: size, shape, and the materials used to create the walls, floor, and ceiling in the room. If you are recording outside (without a room), your problem will not be acoustics so much as sound isolation. It all starts with choosing the best place to record, but sometimes you don’t get the recording room you want. Between the bedroom, basement, and garage, the best place to set up a studio is a bedroom, despite what you may have heard about garage or basement bands.
The two most important considerations for a recording room are size and surrounding material. Think about the length, width, and height of a room. A garage usually has a very high (and sometimes uninsulated) ceiling and a concrete floor: perfect for cars and trucks but horrible for sound. An unfinished basement is usually surrounded by concrete, except for the ceiling. This is great rehearsal space because sound will not travel through the concrete (in or out), but this means that some frequencies will get trapped in the room and muddy the sound (especially if you’re recording loud instruments). Garages and basements can be turned into great places to record, but they require a lot more work than your average bedroom due to their structure and design.
Because a bedroom is a better and easier place to set up a Cubase studio, I will focus on this perspective. If you’re forced to record in a garage or basement, you can use some of these principles to modify your space.
Not all bedrooms are created equal. The first thing to pay attention to is the floor. Concrete on any side of a room (inside or outside the room) will affect the sound. Concrete is great for isolation—blocking unwanted sounds such as passing cars or planes from coming through the walls—but it doesn’t allow sound to resonate, or “breathe.” Sound reflecting off concrete immediately travels in the opposite direction. In a basement, this means the sound travels upward and resonates through the whole house. Solid concrete floors prevent bass frequencies from escaping through the floor, so it’s best if your bedroom floor is not solid concrete, including underneath the carpet. Before you completely write off concrete, I should mention that most pro studios have concrete or brick walls because they’re great at blocking sound from entering the studio. At the same time, studios create a room that is completely suspended within the concrete structure so that sound can travel outside the room (see Figure 3.1 for a rough sketch of a studio wall). Unless you are building a studio from scratch, this is not an option.
Figure 3.1. How concrete is used in studios for sound isolation.
Your standard floor has a plywood platform topped with wood, tile, or carpet. Because wood or tile can be very reflective, it’s often a good idea to at least cover the floor with some sort of decorative rug. Carpet is more than just a soft surface to walk on with bare feet. It’s excellent for absorbing sound reflections and can also prevent annoyances like toe tapping, footsteps, and microphone pickup of floor vibrations. In most rooms, carpet alone can solve the problem of a room sounding “too live” (having a lot of unwanted reflections). In a Cubase home studio, you should always lean more toward achieving a “dead” room (having few noticeable reflections). To test a room’s sound, clap your hands and listen for the sound after the hand clap. If you hear a lot of slapback, this is something you’ll need to fix before recording and especially before mixing in the room.
After fixing the floor with a little carpet, examine the walls and windows. Walls vary a lot. Your standard wall consists of drywall (plaster board), which is excellent for sound isolation, as well as some sound absorption. Whether your walls are insulated will also make a difference in the sound of the room. Walls made of wood can be very resonant (warm-sounding) but have a tendency to create more reflections than you want. Wall hangings (such as paintings, gold records, or guitars) also change a room’s acoustics. Most studios don’t have windows because windows are bad for both reflections and sound isolation. If you do have windows, it’s much better to have double-paned windows or glass brick windows. After spending many hours in rooms without windows, I personally feel that keeping a window or two is worth any extra effort you have to make.
Ceiling height is always an issue in your acoustic studio environment. I prefer the standard eight-foot-high ceilings, but higher ceilings can also work well. For me, a speaker should be located about the same distance from the ceiling as it is from the floor. Ceilings are usually constructed the same way a wall is constructed. In the 1970s and 1980s, it was popular to have “cottage cheese” ceilings. This acoustical ceiling treatment was designed to create quieter rooms, and it works. However, it’s not usually necessary. Sometimes homes have suspended ceilings, like those in office buildings. I recommend avoiding this type of ceiling if possible. The space between the ceiling tiles and the actual ceiling can act as a bass trap and lead you to overcompensate on your bass frequencies (see Figure 3.2).
Figure 3.2. Acoustic ceiling tile as a bass trap—not good.
Before you spend too much money fine-tuning your room, you should also realize that everything you put in it (including yourself) is going to change the way the room sounds. This includes a desk, lamp, mixer, plant, curtains, CD collection, piano, drum set, and ceiling fan. There is no such thing as a perfect room because it is always changing depending on what is in the room. The most wonderful thing about using software such as Cubase is that you aren’t limited to recording just at home. You can take your Cubase setup to most studios and finish a mix or record an 80-piece orchestra at another location. You can live in multiple worlds instead of one little bedroom in your house, and you don’t have to worry about having the most perfect acoustic environment at home, just one that suits your basic needs.