October 15, 2009
by Lisa Montgomery
There’s a certain formula that custom electronics professionals use to determine how far to situate the seats from the screen. In this 14-by-16-foot converted playroom, that placement happened to be against the back wall. Lined with a 14-foot-long custom-made couch, the back provides room for the entire family to sprawl. Unfortunately, it’s also the place where bass collects from the surround-sound system.
“Bass tends to gather in different areas of the room at different levels,” explains Gustavo Serafini, co-owner of Pure Audio Video, Fort Lauderdale, Fla. “The back wall tends to be where most of it congregates.” When there’s too much bass in one area, the audio can end up sounding too “boomy,” which can overshadow important passages of dialogue and special effects. To tame the unruly bass, Pure Audio Video engineered and constructed a total of six bass traps. Made of a combination of plywood and insulation, two of the specially designed treatments were built into each corner of the floor riser; the remaining four went into a custom-built ceiling soffit.
Premade acoustical treatments such as bass traps are available from a variety of manufacturers, but in this case, Pure Audio Video thought it was best to make their own. “Most bass traps are designed to be placed in the corners of a room,” Serafini explains. “But because there was limited wall space, we had to design them to go elsewhere.”
Boomy bass audio wasn’t the only acoustical issue. The nearly square shape of the room would create sound distortion. A combination of reflective and diffusive acoustical treatments was added to preclude this problem. Panels of MDF (medium-density fiberboard) and insulation were mounted to the surface of the ceiling between decorative cypress beams. These uneven treatments help to diffuse the sound so that it’s more immersive and three-dimensional, according to Serafini. Too much diffusion can be a bad thing, though, so five absorptive fiberglass panels were mounted in key areas on the walls to round out the audio and ensure that the special effects would sound realistic and dynamic. Both the ceiling and wall panels were covered in fabric to complement the room design. The chosen colors blend with the paint, so they’re completely indiscernible.
How did Pure Audio Video know what to use and where to put all the various acoustical treatments? Through lots of engineering and testing, says Serafini. A sophisticated acoustical engineering computer program indicated the best locations for the treatments. To ensure the positioning was correct, Pure Audio Video used a sound meter to measure the audio, making sure the bass is smooth and the sound from each speaker arrives at the right time and level for all viewers. Calibration of the equipment was the final step. Together, the engineering, testing and calibration was process tacked a couple of hours onto Pure Audio Video’s labor time, but improved the theater’s audio performance by at least 30 percent, Serafini says.
Acoustical analysis is a service Serafini recommends to all of his home theater clients, one that can add at least $250 to the bottom line. For this project, the acoustical engineering and products accounted for almost 15 percent of the final $170,000 cost, which also included all the construction, furnishings, equipment and labor.
Don’t have the budget for specialty acoustical treatments? You can improve the sound in your media space affordably by using furnishings and materials you already own. According to custom electronics professionals, you’ll need a good mix of absorptive and diffusive items. Such as: good absorbers, window draperies, pillows, areas rugs, plush furniture, good diffusers, bookshelves, wall art, wood moldings.
Click here to view additional photos and information, including the room’s dropdown projector.
Lisa Montgomery has been writing about home technology for 15 years, with a focus on the impact of electronics on a modern lifestyle.