How about we take a walk together and think about this gig you’ve just been offered. But first let’s agree on our starting point. I am not sure where you are, but I am in Downtown Los Angeles right now. So even if only by imagination, you’re coming here with me for two reasons. First, it’s the city where surround sound was born. It is home to THX, Dolby, DTS, and SDDS. Second, movies are shot right here on a daily basis, and you’ve probably seen many of them. It’ll be easier to make references.
Imagine you just moved into a loft on Sixth and Main Street in Downtown LA, an open space of 1001 ft² or 93 m². Its shape is rectangular and the ceiling is 16 ft or about 5 m high along with a set of windows from floor to ceiling across the widest wall. These are good dimensions for a sound studio. When looking for a studio space you should avoid any cubic rooms and stay away from rooms where any two dimensions are multiples of one another, because it would be hard to control room modes. You can calculate standing waves location peaks by using online calculators.
You look around your new space. What’s good about your situation is the ability to start from scratch. You could even calculate the most acoustically ideal scenario within a range of your room dimensions and then apply some sizing. How about instead of using the whole space for the studio, opt for building a wall at one end of your room and occupy a smaller space with a scaled-down system?
There are pros and cons of monitoring audio signal in smaller and bigger control rooms, especially when considering multi-channel sound. Before we start our research on that subject, we will get familiar with the “cocktail party effect” which helps us to spice up the topic with some sound design. The cocktail party effect is most simply the process of selective listening, and it works as a binaural (listening with two ears) effect. With our auditory system, we are able to localize at least two sound sources and assign the correct characteristics to these sources simultaneously. After localization, we can extract selective signals out of a mix of interfering sounds. After being accustomed to a specific sound repetitively over a time, our awareness of this sound increases. That’s why in a crowded space if somebody calls your name you react spontaneously. We use this effect on an everyday basis. We use it when mixing audio and altering different arrangement elements. We also use it in sound design.
Let’s see this in action. You put your jacket on — you can hear the linen fabric rustling on your shoulders. You pick up your keys from the marble kitchen island. They slide through your fingers leaving a cold “whoosh”, followed by slight resonant ringing. Then they fall down on the stone floor making a spooky sound. Your furniture hasn’t arrived yet so the space has a nice reverberation time.
You hear a car horn beep, a sound with high directivity. You raise your eyebrows, then look around. One window in the corner is open. You slide it down with its chain mechanism noise clanking until it finishes with a firm wooden thud. The loft windows are the originals from 1905, far from ideal, but when closed the outside noise becomes steady enough that you notice the central air is on.
You look around eyeballing the space. Considering these generous dimensions, you could actually monitor your system playing at 85 dB SPL without the feeling that you are smashing yourself or your clients with very high sound pressure. The subwoofer’s low air will have time to dissolve with smooth release. Your loft could even be a small dubbing stage… ahh the possibilities. You grab your keys and walk outside without bothering to lock the door.
The Pacific Electric loft you now call home is in the historical building known as LA’s first skyscraper. It oozes character. The management is cool so you can do whatever you want, of course within limits. As you walk through the corridor, your footsteps leave a few random scuff sounds. “37 footstep, marble male walk slowly on marble floor footstep” is the name of the sample FX you would look up in the sound library if you want to redesign it in post. The white granite is covering the floors to the mid-walls. The corridor is long and so is the time of foley footsteps reverberations. Then after you turn left, you hear a “bang” down the hall, an undistinguished sound at first — but after it dies you hear the glass window pane rattling. It’s your neighbor who is not always in a perfect mood. A painter. “Lots of canvas at a good rate,” he said one occasion, “I’ll hook you up, Ok?” Ok, it should work with your plan to build some “custom” acoustic panels. You can get some wooden boards at the hardware store in Hollywood. If you want to get your studio in order in terms of room acoustics, you have to suppress first reflections by deploying low frequency absorption at least on the ceiling and two or four walls. Also diffusion should be deployed as much as possible when working with surround.
Where to next? Well, right now you are standing in front of the elevator and the window is half-open. You hear the classic sounding hum of the street with the distinction of separate sounds; it’s only the third floor. Car and bus tires create a phasing blend of sounds crossing Main Street and heading south on Sixth. Then once it disappears behind the corner, this food group partially loses its high frequencies and the sounds become hollow and more distant. Bouncing motorcycle mufflers grumble against tall building walls, spiking at around 3-5 kHz. Below you hear your favorite neighborhood character, Ricky the Pirate, standing in front of the building entrance talking to strangers in his raspy, rambling, happy slang.